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Malaria
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Malaria is infection with Plasmodium sp. Symptoms and signs include fever (which may be periodic), chills, sweating, hemolytic anemia, and splenomegaly. Diagnosis is by seeing Plasmodium in a peripheral blood smear. Treatment and prophylaxis depend on the species and drug sensitivity and include the fixed combination of atovaquone and proguanil, artemisinin derivatives, doxycycline, mefloquine, chloroquine, and quinine. Patients infected with P. vivax and P. ovale also receive primaquine to prevent relapse.

Malaria is endemic in Africa, much of South and Southeast Asia, North and South Korea, Mexico, Central America, Haiti, the Dominican Republic, South America (including northern parts of Argentina), the Middle East (including Turkey, Syria, Iran, and Iraq), and Central Asia. There are 300 to 500 million infected people worldwide, with about 655,000 deaths yearly, mostly in children < 5 yr in Africa.

Pathophysiology

The Plasmodium species that infect humans are:

• P. falciparum | P. vivax | P. ovale | P. malariae

The basic elements of the life cycle are the same for all Plasmodium sp. Transmission begins when a female Anopheles mosquito feeds on a person with malaria and ingests blood containing gametocytes. During the following 1 to 2 wk, gametocytes inside the mosquito reproduce sexually and produce infective sporozoites. When the mosquito feeds on another human, sporozoites are inoculated and quickly reach the liver and infect hepatocytes. The parasites mature into tissue schizonts within hepatocytes. Each schizont produces 10,000 to 30,000 merozoites, which are released into the bloodstream 1 to 3 wk later when the hepatocyte ruptures. Each merozoite can invade an RBC and there transform into a trophozoite. Trophozoites grow and develop into erythrocyte schizonts; schizonts produce further merozoites, which 48 to 72 h later rupture the RBC and are released in plasma. These merozoites then rapidly invade new RBCs, repeating the cycle. Some trophozoites develop into gametocytes, which are ingested by an Anopheles mosquito. They undergo sexual union in the gut of the mosquito, develop into oocysts, and release infective sporozoites, which migrate to the salivary glands.

With P. vivax and P. ovale (but not P. falciparum or P. malariae), tissue schizonts may persist as hypnozoites in the liver for years. Relapse of P. ovale has occurred as late as 6 yr after an episode of symptomatic malaria, and the infection was transmitted by blood transfusion from a person who was exposed 7 yr before donating blood. These dormant forms serve as time-release capsules, which cause relapses and complicate chemotherapy because they are not killed by most antimalarial drugs, which typically act on bloodstream parasites.

The pre-erythrocytic (hepatic) stage of the malarial life cycle is bypassed when infection is transmitted by blood transfusions, by sharing of contaminated needles, or congenitally. Therefore, these modes of transmission do not cause latent disease or delayed recurrences.

Rupture of RBCs during release of merozoites is associated with the clinical symptoms. If severe, hemolysis causes anemia and jaundice, which are worsened by phagocytosis of infected RBCs in the spleen. Anemia may be severe in P. falciparum or chronic P. vivax infection but tends to be mild in P. malariae infection.

Falciparum malaria

Unlike other forms of malaria, P. falciparum causes microvascular obstruction because infected RBCs adhere to vascular endothelial cells. Ischemia develops with resultant tissue hypoxia, particularly in the brain, kidneys, lungs, and GI tract. Hypoglycemia and lactic acidosis are other potential complications.

Resistance to infection

Most West Africans have complete resistance to P. vivax because their RBCs lack the Duffy blood group, which is required for the attachment of P. vivax to RBCs; many African Americans also have such resistance. The development of Plasmodium in RBCs is retarded in patients with hemoglobin S, hemoglobin C, thalassemia, G6PD deficiency, or elliptocytosis.

Previous infections provide partial immunity. Once residents of hyperendemic areas leave, acquired immunity wanes over time (months to years), and symptomatic malaria may develop if they return home and become reinfected.

Symptoms and Signs

The incubation period is usually 12 to 17 days for P. vivax, 9 to 14 days for P. falciparum, 16 to 18 days or longer for P. ovale, and about 1 mo (18 to 40 days) or longer (years) for P. malariae. However, some strains of P. vivax in temperate climates may not cause clinical illness for months to > 1 yr after infection.

Manifestations common to all forms of malaria include:

• Fever and rigor—the malarial paroxysm
• Anemia
• Jaundice
• Splenomegaly
• Hepatomegaly

The malarial paroxysm coincides with release of merozoites from ruptured RBCs. The classic paroxysm starts with malaise, abrupt chills and fever rising to 39 to 41° C, rapid and thready pulse, polyuria, headache, myalgia, and nausea. After 2 to 6 h, fever falls, and profuse sweating occurs for 2 to 3 h, followed by extreme fatigue. Fever is often hectic at the start of infection. In established infections, malarial paroxysms typically occur every 2 to 3 days depending on the species; intervals are not rigid.

Splenomegaly usually becomes palpable by the end of the first week of clinical disease but may not occur with P. falciparum. The enlarged spleen is soft and prone to traumatic rupture. Splenomegaly may decrease with recurrent attacks of malaria as functional immunity develops. After many bouts, the spleen may become fibrotic and firm or, in some patients, becomes massively enlarged (tropical splenomegaly). Hepatomegaly usually accompanies splenomegaly.

P. falciparum causes the most severe disease because of its microvascular effects. It is the only species likely to cause fatal disease if untreated; nonimmune patients may die within days of their initial symptoms. Patients with cerebral malaria may develop symptoms ranging from irritability to seizures and coma. Acute respiratory distress syndrome (ARDS), diarrhea, icterus, epigastric tenderness, retinal hemorrhages, algid malaria (a shocklike syndrome), and severe thrombocytopenia may also occur. Renal insufficiency may result from volume depletion, vascular obstruction by parasitized erythrocytes, or immune complex deposition. Hemoglobinemia and hemoglobinuria resulting from intravascular hemolysis may progress to blackwater fever (so named based on the dark color of the urine), either spontaneously or after treatment with quinine. Hypoglycemia is common and may be aggravated by quinine treatment and associated hyperinsulinemia. Placental involvement may lead to low birth weight, spontaneous abortion, stillbirth, or congenital infection.

Diagnosis

• Light microscopy of blood (thin and thick smears)
• Rapid blood assays that detect Plasmodium antigens or enzymes

Fever and chills in an immigrant or traveler returning from an endemic region should prompt immediate assessment for malaria. Most cases occur within the first 6 mo, but onset may take up to 2 yr or, rarely, longer.

Malaria can be diagnosed by finding parasites on microscopic examination of thick or thin blood smears. The infecting species (which determines therapy and prognosis) is identified by characteristic features on smears. Blood smears should be repeated at 4- to 6-h intervals if the initial smear is negative.

Thin blood smears stained with Wright-Giemsa stain allow assessment of parasite morphology within RBCs, often speciation, and determination of percentage parasitemia. Thick smears are more sensitive but more difficult to prepare and interpret as the RBCs are lysed before staining. Sensitivity and accuracy of the results depend on the examiner's experience.

Commercial rapid assays are based on the presence of certain plasmodium antigens or enzymatic activities. Assays may involve detection of a histidine-rich protein 2 (HRP-2) associated with malaria parasites (especially P. falciparum and P. vivax) and detection of plasmodium-associated lactate dehydrogenase (pLDH). The rapid tests are comparable in sensitivity to microscopy in detecting low levels of parasitemia; However, they do not differentiate single infection from concurrent infection with more than one Plasmodium sp or allow speciation except for P. falciparum.

Light microscopy and rapid assays are complementary tests, and both should be done when available. They have similar sensitivity. Negative results in both does not exclude malaria in a patient with low parasitemia.

Treatment
Antimalarial drugs are chosen based on the clinical manifestations, the infecting Plasmodium sp, known resistance patterns of strains in the area of acquisition, and the efficacy and adverse effects of drugs available.

• P. falciparum or unidentified species acquired in all malarious regions except those specified as chloroquine-sensitive—Oral drug - Atovaquone

• P. falciparum and unidentified species acquired in chloroquine-sensitive areas (Central America west of Panama Canal, Haiti, Dominican Republic, most of the Middle East) and P. malariae and P. knowlesi in all regions —Oral drug - Chloroquine

• P. vivax (unless from chloroquine-resistant area) or P. ovale—Oral drugs - Chloroquine phosphate or hydroxychloroquine

• P. vivax acquired in areas known to harbor chloroquine-resistant P. vivax l (Papua New Guinea, Indonesia)—Oral drugs - Quinine sulfate plus Doxycycline or Tetracycline

• Severe infection, all Plasmodium —Parenteral drugs - Quinidine plus one of the following: Doxycycline or Tetracycline or Clindamycin.

CLINICAL VIGNETTES

A 24-year-old man takes an exotic “around-the-world” vacation to Europe, Africa, India and China. On his holiday, he has frequent sexual encounters and does not use condoms. In addition, he is bitten by mosquitoes many times. On his return, he notes fever, and his physician finds generalized lymphadenopathy. Which of the following is least likely to account for both these symptoms?

A. Human immunodeficiency virus type 1 (HIV-1)
B. Infectious mononucleosis
C. Malaria
D. Syphilis
E. Cat-scratch disease

The answer is C. Malaria is characterized by lack of lymphadenopathy, although splenomegaly and ever are characteristic. Although generalized enlargement of lymph nodes is a nonspecific finding, it often can lead to the diagnosis of a clinical entity. When the lymphadenopathy is coupled with fatigue and an atypical lymphocytosis, infectious mononucleosis is suggested. This syndrome most often is caused by Epstein–Barr virus, but a similar clinical picture is produced by cytomegalovirus infection. The infections can be distinguished by using serologic tests (e.g., Monospot test) or specific antibodies. Secondary syphilis also should be considered in patients with adenopathy of short duration; this can be confirmed on the basis of serologic tests and the finding of an appropriate rash. Reactive, hyperplastic lymph nodes are common in HIV-1 infection. For this patient, all of these are possibilities, but the malaria would not account for the enlarged lymph nodes. Cat-scratch disease usually causes enlarged lymph glands, with stellate microabscesses apparent histologically.

Which of the following drugs is the first choice for malaria prophylaxis in an area of the world in which the plasmodium is known to be resistant to multiple drugs?

A. Hydroxychloroquine  |  B. Doxycycline  |  C. Halofantrine  | D. Mefloquine  | E. Pyrimethamine

The answer is B. Doxycycline is presently the first choice for malaria prophylaxis in areas known to harbor multiple drug resistance.

A 30-year-old woman recently back from a photographic safari trip to Tanzania presents with headache, fever with temperature spikes of 40.6􏰁C (105􏰁F), and scleral icterus. Physical examination reveals tender hepatosplenomegaly. Laboratory data show an increase in the liver transaminases. A complete blood cell count shows a normocytic anemia and an increased corrected reticulocyte count. A direct Coombs’ test result is negative. Results of a urine dipstick test for blood are positive. A peripheral blood smear shows many red blood cells with one to three ringlike structures. Which of the following is the most likely diagnosis?

A. Autoimmune hemolytic anemia
B. Congenital spherocytosis
C. Glucose-6-phosphate dehydrogenase (G6PD) deficiency
D. Hemolytic anemia caused by pyruvate kinase deficiency
E. Plasmodium falciparum malaria

The answer is E. Four Plasmodium species cause malaria: P. falciparum, P. ovale, P. malariae, and P. vivax. P. falciparum infection is generally the most dangerous. An estimated 30,000 travelers from developed counties to tropical areas are infected with malaria annually, and several hundred die. The patient described in the vignette has P. falciparum malaria (choice E), which is endemic in many east African countries including Tanzania. The peripheral blood findings in the vignette described multiple ring forms, a characteristic finding in P. falciparum infections. The tertian fever pattern (recurring every other day, with occasional fever spikes) correlates with intravascular hemolysis, which causes hemoglobinuria (positive dipstick test result for blood), and extravascular hemolysis leads to jaundice, as splenic macrophages remove parasitized red blood cells (RBCs) and degrade the hemoglobin into unconjugated bilirubin. This hemolytic anemia is associated with an increase in the corrected reticulocyte count. Hepatosplenomegaly is present after the fourth day in all of the malarias.

Malaria is transmitted to humans primarily by the bite of a female Anopheles mosquito. Because P. falciparum malaria produces a greater degree of parasitism of red blood cells resulting in cytoadherence of parasitized red cells in capillaries and postcapillary venules, it is the most severe form of malaria. Complications include central nervous system hemorrhage, disseminated intravascular coagulation, acute respiratory distress syndrome, and liver cell necrosis with an increase in transaminases.

When autoimmune hemolytic anemia (choice A) is suspected, a direct Coombs’ test is ordered. It detects IgG and C3b on the surface of the RBCs. The negative Coombs’ test result in this patient rules out an autoimmune hemolytic anemia. Congenital spherocytosis (choice B) is an autosomal dominant disorder that causes hemolytic anemia with jaundice and splenomegaly. It is not associated with a spiking fever or the intraerythrocytic ring forms that are present in this patient, and erythrocytes have a spherocytic or oval shape. Glucose-6-phosphate dehydrogenase (G6PD) deficiency (choice C) is an X-linked recessive disorder (patient is a woman) that causes a predominantly intravascular type of hemolytic anemia that presents with hemoglobinuria. The less predominant extravascular hemolytic component is responsible for producing jaundice. The RBCs do not have intraerythrocytic ring forms. Pyruvate kinase deficiency (choice D) is an autosomal recessive disorder associated with a hemolytic anemia. The peripheral blood shows shrunken and spiculated RBCs with no intraerythrocytic inclusions.
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Osler-Weber-Rendu syndrome (Hereditary Hemorrhagic Telangiectasia)
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Hereditary Hemorrhagic Telangiectasia
(Osler-Weber-Rendu Syndrome)

Hereditary hemorrhagic telangiectasia is a hereditary disorder of vascular malformation transmitted as an autosomal dominant trait affecting men and women.

More than 80% of patients have mutations in the endoglin ( ENG ) gene, which encodes a receptor for transforming growth factor beta-1 (TGF-β1) and TGF-β3 or in the MADH4 gene, which encodes SMAD4, a protein active in the TGF-β signalling pathway.

Symptoms and Signs

The most characteristic lesions are small red-to-violet telangiectatic lesions on the face, lips, oral and nasal mucosa, and tips of the fingers and toes. Similar lesions may be present throughout the mucosa of the GI tract, resulting in recurrent GI bleeding. Patients may experience recurrent, profuse nosebleeds. Some patients have pulmonary arteriovenous fistulas. These fistulas may cause significant right-to-left shunts, which can result in dyspnea, fatigue, cyanosis, or polycythemia. However, the first sign of their presence may be a brain abscess, transient ischemic attack, or stroke as a result of infected or noninfected emboli. Cerebral or spinal arteriovenous malformations occur in some families and may cause subarachnoid hemorrhage, seizures, or paraplegia. Hepatic arteriovenous malformations may lead to liver failure and high output heart failure.

About 95% of affected individuals eventually have recurrent epistaxis, with one third having onset by age ten years and 80-90% by age 21 years. However, many do not have nosebleeds that are frequent or severe enough to cause anemia or to result in medical treatment or consultation. While a similar proportion of affected individuals eventually develop telangiectases of the face, mouth, or hands, the average age of onset is generally later, in the decade of the 30s or 40s. Telangiectases vary in size from pinpoint to that of a small pea. Telangiectases can also occur in the gastrointestinal tract, most commonly in the stomach and small intestine. GI bleeding is usually low-grade in the 20-25% of patients that develop this symptom, but is often persistent and can become increasingly severe with age. Epistaxis and/or GI bleeding can cause mild to severe anemia.

Pulmonary (arteriovenous malformations) AVMs have been reported to occur in approximately 40% of patients and Cerebral AVMs in 5-20% which may present with anything from seizure to cerebral hemorrhage. Most pulmonary AVMs present as a consequence of blood shunting through the abnormal vessel and bypassing the capillary bed, not hemorrhage. Shunting of air, thrombi, and bacteria through pulmonary AVMs, thus bypassing the filtering capabilities of the lungs, may cause transient ischemic attacks (TIAs), embolic stroke, and cerebral or other abscess.

Diagnosis
• Clinical evaluation
• Sometimes endoscopy or angiography
• Sometimes genetic testing
• CBC and FOBT

Diagnosis is based on the finding of characteristic arteriovenous malformations on the face, mouth, nose, and digits. Endoscopy or angiography is sometimes needed. Laboratory findings are usually normal except for iron deficiency anemia in many patients.

Testing for the ENG and SMAD4 mutations may be helpful in some patients with atypical features or for screening asymptomatic family members.

Screening

If a family history of pulmonary, hepatic, or cerebral arteriovenous malformations exists, screening at puberty and at the end of adolescence with pulmonary CT, hepatic CT, and cerebral MRI is recommended.

Treatment

• Sometimes laser ablation, surgical resection, or embolization of symptomatic arteriovenous malformations
• Supplemental iron therapy
• Possibly blood transfusions
• Sometimes antifibrinolytic drugs (eg, aminocaproic acid, tranexamic acid)

Treatment for most patients is supportive, but accessible telangiectasias (eg, in the nose or GI tract via endoscopy) may be treated with laser ablation. Arteriovenous fistulas may be treated by surgical resection or embolization. Repeated blood transfusions may be needed; therefore, immunization with hepatitis B vaccine is important. Many patients require continuous iron therapy to replace iron lost in repeated mucosal bleeding; many patients require parenteral iron and sometimes erythropoietin. Treatment with drugs that inhibit fibrinolysis, such as aminocaproic acid or tranexamic acid may be beneficial.

Key Points
• Nasal and GI telangiectasias may cause significant external hemorrhage.
• Vascular malformations in the CNS, lungs, and liver may bleed; hepatic and pulmonary malformations may cause significant shunting.
• Accessible mucosal telangiectasias may be treated with laser ablation; embolization or surgical resection may be needed for other vascular malformations.
• Many patients require iron supplements because of chronic blood loss.

CLINICAL VIGNETTES

A 20-year-old male presents to your office with complaints of recurrent profuse epistaxis. Upon physical exam you notice several small red-to-violet telangiectatic lesions on his face, lips, oral and nasal mucosa, and tips of his fingers and toes. When questioned further he admits to also experiencing dyspnea and fatigue. He states he as a relative who has similar symptoms and died of a stroke. You decide to order a compete blood count and a CT of the chest and head. The most likely diagnosis is

A. CREST Syndrome
B. Pediatric Syphilis
C. Rosacea
D. Osler-Weber-Rendu (hereditary hemorrhagic telangiectasia)
E. Von Willebrand's disease

During a periodic physical examination of a 24-year-old man, you note multiple small, red, soft, well-demarcated papules on his lips as well as his hard palate and tongue. On further questioning, he reports frequent nose bleeds in his early adult years. He recalls the slow appearance of these asymptomatic red papules on his lips since his teen years. He assumed this was just something he inherited from his father since many relatives from his father's side have similar lesions. He is otherwise well, without feelings of fatigue, nausea, or night sweat. The most appropriate next step is to

A. check complete blood count and stool for occult blood
B. inquire about alcohol consumption
C. order a CT scan of the brain to rule out central nervous system hemangioblastomas
D. reassure him that these are acquired hemangiomas without associated complications
E. tell the patient these are port wine stains and are associated with increased risk of seizure and glaucoma

The correct answer is A. Osler-Weber-Rendu, also known as hereditary hemorrhagic telangiectasia, is an autosomal dominant vascular condition characterized by telangiectasias in the skin, mucous membranes, and internal organs, often complicated by epistaxis or gastrointestinal bleeding. The vascular lesions appear during the second and third decades of life. Most common locations are lips, nasal mucosa, tongue, palms, palate, and soles. Two common complications are melena and anemia. Polycystic kidneys have been reported in some patients.

Spider telangiectasia is associated with alcohol consumption (choice B) and presents as small dilated vessels surrounded by radiating fine channels. They are most common on the chest wall and face. They are also frequently associated with hyperestrinism as seen in chronic liver disease, alcoholism, and pregnancy.

Von Hippel-Lindau disease (choice C) is an autosomal dominant disorder that is also marked by hemangioblastomas of the cerebellum, brain stem, and retina as well as adenomas and cysts of the liver, kidneys, and pancreas. It is also associated with increased risk of renal-cell carcinoma. Cavernous hemangioma of the head and neck is the main cutaneous finding.

Acquired hemangiomas (choice D), also known as cherry angiomas, is incorrect because these lesions are small, bright-red papules composed of ectatic vessels. They generally arise in middle age, usually on the abdomen. They tend not to grow rapidly in size and do not involute spontaneously.

Port wine stain (choice E) is incorrect because this is a congenital capillary malformation which is commonly associated with soft tissue and skeletal hypertrophy. Sturge Weber syndrome is rare, affecting 2-11% of facial port wine stain patients and can be associated with seizure and ocular changes such as glaucoma and visual loss.

A 23-year-old female presents with recurrent unprovoked epistaxis. The patient’s mother is known to have hereditary hemorrhagic telangiectasia. Contrast echocardiography is recommended to screen for which one of the following frequently associated conditions?

A. Atrioseptal defect
B. Ventricular septal defect
C. Aortic root aneurysm
D. Pulmonary arteriovenous malformation
E. Myocardial perfusion defects

ANSWER: D. Pulmonary arteriovenous malformations are found in 15%–40% of patients with hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome. All patients with possible or confirmed HHT should be screened for pulmonary arteriovenous malformations with contrast echocardiography. While contrast echocardiography is used to detect atrioseptal and ventricular septal defects, neither of these conditions is particularly prevalent in HHT. Aortic aneurysms and myocardial perfusion defects are also not associated with HHT.
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Giardiasis
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Giardiasis is infection with the flagellated protozoan Giardia intestinalis (lamblia). Infection can be asymptomatic or cause symptoms ranging from intermittent flatulence to chronic malabsorption. Diagnosis is by identifying the organism in fresh stool or duodenal contents or by assays of Giardia antigen in stool. Treatment is with metronidazole, tinidazole, or nitazoxanide or, during pregnancy, paromomycin.

Giardia trophozoites firmly attach to the duodenal and proximal jejunal mucosa and multiply by binary fission. Some organisms transform into environmentally resistant cysts that are spread by the fecal-oral route. Waterborne transmission is the major source of giardiasis. Transmission can also occur by ingestion of contaminated food and by direct person-to-person contact, especially in mental institutions and day care centers or between sex partners. Giardia cysts remain viable in surface water and are resistant to routine levels of chlorination. Wild animals may also serve as reservoirs. Thus, mountain streams as well as chlorinated but poorly filtered municipal water supply systems have been implicated in waterborne epidemics.

Symptoms and Signs
Many cases are asymptomatic. However, asymptomatic people can pass infective cysts.

Symptoms of acute giardiasis usually appear 1 to 14 days (average 7 days) after infection. They are usually mild and include watery malodorous diarrhea, abdominal cramps and distention, flatulence, eructation, intermittent nausea, epigastric discomfort, and sometimes low-grade malaise and anorexia. Acute giardiasis usually lasts 1 to 3 wk. Malabsorption of fat and sugars can lead to significant weight loss in severe cases. Neither blood nor WBCs are present in stool.

A subset of infected patients develop chronic diarrhea with foul stools, abdominal distention, and malodorous flatus. Substantial weight loss may occur. Chronic giardiasis occasionally causes failure to thrive in children.

Diagnosis
• Enzyme immunoassay for antigen in stool
• Microscopic examination of stool

Enzyme immunoassay to detect parasite antigen in stool is more sensitive than microscopic examination. Characteristic trophozoites or cysts in stool are diagnostic, but parasite excretion is intermittent and at low levels during chronic infections. Thus, microscopic diagnosis may require repeated stool examinations. Sampling of the upper intestinal contents can also yield trophozoites but is seldom necessary. Specific DNA probes exist. Testing is available at the Centers for Disease Control and Prevention (CDC) and is likely to become increasingly available at reference laboratories in the future.

Treatment
• Tinidazole, metronidazole, or nitazoxanide

For symptomatic infections, metronidazole 250 mg po tid in adults (5 mg/kg po tid in children) for 5 to 7 days can be used. Adverse effects include nausea, headaches, and a disulfiram-like effect if alcohol is consumed concurrently. Tinidazole 2 g po once in adults (50 mg/kg [maximum 2 g] po in children) is as effective as and less toxic than metronidazole. Neither of these drugs should be taken with alcohol.

Nitazoxanide is given orally for 3 days as follows: age 1 to 3 yr, 100 mg bid; age 4 to 11 yr, 200 mg bid; and age > 12 yr (including adults), 500 mg bid. It is available in liquid form for children.

Furazolidone and quinacrine are effective but are now rarely used because of potential toxicity.

Metronidazole and tinidazole should not be given to pregnant women. Nitazoxanide is in pregnancy category B. If therapy cannot be delayed because of symptoms, the nonabsorbable aminoglycoside paromomycin (8 to 11 mg/kg po tid for 5 to 10 days) is an option.

Prevention
Prevention requires appropriate public water treatment, hygienic food preparation, and appropriate fecal-oral hygiene. Water can be decontaminated by boiling. Giardia cysts resist routine levels of chlorination. Disinfection with iodine-containing compounds is variably effective and depends on the turbidity and temperature of the water and duration of treatment. Some handheld filtration devices can remove Giardia cysts from contaminated water, but the efficacy of various filter systems has not been fully assessed.

Key Points
• The major source of giardiasis is waterborne transmission, including via fresh-appearing mountain streams and poorly filtered municipal water supplies.
• Giardia cysts resist routine levels of chlorination, and disinfection with iodine-containing compounds is variably effective.
• Enzyme immunoassay to detect parasite antigen in stool is preferred because it is more sensitive than microscopic examination.
• For symptomatic patients, use tinidazole, metronidazole, or nitazoxanide.

CLINICAL VIGNETTES

A 26-year-old man comes to the office because of an 11-day history of crampy abdominal pain, non-bloody diarrhea, bloating, and increased flatus. He went on a camping trip 3 weeks ago where he and his friends cooked their own food and drank water from streams. He tells you that two of the three other guys that he went with have similar symptoms. They are both patients of yours too. His temperature is 37.2 C (99.0 F), blood pressure is 110/70 mm Hg, and pulse is 60/min. Physical examination shows mild diffuse abdominal tenderness and guaiac negative stool. Examination of a wet mount of a stool sample under the microscope fails to reveal leukocytes. The most appropriate next step is to

A. ask him to bring in 5 stool samples over the next 5 days
B. obtain a sample of duodenal fluid
C. obtain a stool sample for ova and parasites
D. prescribe a 5-day course of metronidazole
E. reassure him that this condition is self-limited and that no treatment is indicated

The correct answer is C. This patient most likely has acute giardiasis, which is a common infection that affects hikers and campers that drink water from streams. The symptoms include diarrhea or loose stools, bloating, flatus, abdominal pain, nausea, and vomiting. The diagnosis can be established by identifying cysts or trophozoites in the stool or duodenal fluid. The most appropriate next step in this case is to examine his stool for ova and parasites.

Asking him to bring in 5 stool samples over the next 5 days (choice A) is a bit ridiculous. This patient most likely has acute giardiasis. A stool sample sent for ova and parasites may establish the diagnosis and then he should be treated with metronidazole. It is recommended that at least 3 stool samples be examined to establish the diagnosis of giardiasis, but asking him to do this for 5 days will most likely lead to an unhappy and noncompliant patient.

In this patient who most likely has acute giardiasis, obtaining a sample of duodenal fluid (choice B) is excessive and not cost effective. It may be helpful in establishing the diagnosis, but it should not necessarily be done in every case of acute giardiasis. It may be useful in patients that you suspect have chronic giardiasis that cannot be proven with less expensive and invasive studies.

Since this patient most likely has giardiasis, a stool sample should be examined for ova and parasites. After this establishes the diagnosis, it is appropriate for you to prescribe a 5-day course of metronidazole (choice D).

This patient most likely has acute giardiasis and therefore it is incorrect to reassure him that this condition is self-limited and that no treatment is indicated (choice E). Untreated giardiasis may lead to chronic infection.

A 24-year-old female college student presents to the physician’s office with complaints of watery diarrhea, abdominal cramping and bloating, and nausea. She returned from a backpacking trip in the mountains 4 days previously. The patient was in moderate distress, had mild pyrexia, moderate tachycardia, and normal blood pressure and respiratory rate. There was no pallor or cyanosis. She was mildly dehydrated, and showed no signs of icterus. The cardiovascular system was normal except for sinus tachycardia. The respiratory system was normal. The abdomen was soft, and there was diffuse tenderness without guarding. No masses were felt, and there was no organomegaly. Bowel sounds were increased. A complete blood count revealed leukocytosis, and the hematocrit was elevated. Her serum electrolytes revealed moderate hypernatremia but were otherwise unremarkable. Microscopic examination of stool revealed pear- shaped, dorsally convex, flattened parasites with two nuclei and four pairs of flagella. Which of the follow- ing represents the best treatment for this patient?

A. Reassurance  |  B. Penicillin  |  C. Tetracycline  |  D. Azidothymidine (AZT)  | E. Metronidazole

The answer is E. This patient is suffering from giardiasis, a widespread protozoal disease that causes diarrhea, abdominal pain, bloating, belching, flatus, nausea, and vomiting. Surface waters, such as mountain streams, are at risk for contamination. Treatment with metronidazole (choice E) or quinacrine is effective, with cure rates over 80%. Infections are caused by ingestion of the hardy cysts, which exist in the duodenum and live and multiply in the small intestine. Acute giardiasis usually lasts for more than a week, but untreated infections can become chronic and last for years. Therefore, reassurance (choice A) is not the appropriate treatment. Humoral responses appear to be important for development of immunity because patients with hypogammaglobulinemia commonly suffer from prolonged, severe infections that are resistant to treatment.

Penicillin (choice B) and tetracycline (choice C) are effective against bacteria but have no effect on protozoa. Azidothymidine (AZT; choice D) is used to combat human immunodeficiency virus (HIV) infections and has no antiprotozoal activity.
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Pneumocystis Jirovecii Pneumonia
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Pneumocystis jirovecii is a common cause of pneumonia in immunosuppressed patients, especially in those infected with HIV and in those receiving systemic corticosteroids. Symptoms include fever, dyspnea, and dry cough. Diagnosis requires demonstration of the organism in an induced sputum specimen or bronchoscopic sample. Treatment is with antibiotics, usually trimethoprim/sulfamethoxazole or dapsone/trimethoprim, clindamycin/primaquine, atovaquone, or pentamidine. Patients with Pao 2 < 70 mm Hg receive systemic corticosteroids. Prognosis is generally good with timely treatment.

P. jirovecii is a ubiquitous organism transmitted by aerosol route and causes no disease in immunocompetent patients. However, some patients are at risk of developing P. jirovecii pneumonia:

• Patients with HIV infection and CD4+ counts < 200/μL
• Organ transplant recipients
• Patients with hematologic cancers
• Patients taking corticosteroids

Most patients have fever, dyspnea, and a dry, nonproductive cough that evolves over several weeks (HIV infection) or over several days (other causes of compromised cell-mediated immunity). Dyspnea is common.

Diagnosis
• Chest x-ray
• Pulse oximetry
• Histopathologic confirmation

Patients should have chest x-ray and assessment of oxygenation by pulse oximetry.

Chest x-ray characteristically shows diffuse, bilateral perihilar infiltrates, but 20 to 30% of patients have normal x-rays.

Hypoxemia may be present even when chest x-ray shows no infiltrate; this finding can be an important clue to diagnosis. When pulse oximetry is abnormal, ABGs are often obtained to show severity of hypoxemia (including an increase in the alveolar-arterial O 2 gradient).

If done, pulmonary function tests show altered diffusing capacity (although this is rarely done as a diagnostic test).

Histopathologic demonstration of the organism is needed for confirmation of the diagnosis. Methenamine silver, Giemsa, Wright-Giemsa, modified Grocott, Weigert-Gram, or monoclonal antibody stain is used. Sputum specimens are usually obtained by induced sputum or bronchoscopy. Sensitivity ranges from 30 to 80% for induced sputum and is > 95% for bronchoscopy with bronchoalveolar lavage.

Prognosis

Overall mortality for P. jirovecii pneumonia in hospitalized patients is 15 to 20%. Risk factors for death may include previous history of P. jirovecii pneumonia, older age, and, in HIV-infected patients, CD4+ cell count < 50/μL

Treatment
• Trimethoprim/sulfamethoxazole
• Corticosteroids if Pa o 2 < 70 mm Hg

Treatment is with trimethoprim/sulfamethoxazole (TMP/SMX) 4 to 5 mg/kg IV or po tid for 14 to 21 days. Treatment can be started before diagnosis is confirmed because P. jirovecii cysts persist in the lungs for weeks. Adverse effects of treatment are more common among patients with AIDS and include rash, neutropenia, hepatitis, and fever.

Alternative regimens, which are also given for 21 days, are

• Pentamidine 4 mg/kg IV once/day
• Atovaquone 750 mg po bid
• Trimethoprim 5 mg/kg po qid with dapsone 100 mg po once/day
• Clindamycin 300 to 900 mg IV q 6 to 8 h with primaquine base 15 to 30 mg/day po

The major limitation of pentamidine is the high frequency of toxic adverse effects, including acute kidney injury, hypotension, and hypoglycemia. Adjunctive therapy with corticosteroids is recommended for patients with a Pa o 2 < 70 mm Hg. The suggested regimen is prednisone 40 mg po bid (or its equivalent) for the first 5 days, 40 mg po once/day for the next 5 days (or 20 mg bid), and then 20 mg po once/day for the duration of treatment.

Prevention

HIV-infected patients who have had P. jirovecii pneumonia or who have a CD4+ count < 200/μL should receive prophylaxis with TMP/SMX 80/400 mg once/day; if this regimen is not tolerated, dapsone 100 mg po once/day or aerosolized pentamidine 300 mg once/month can be used. These prophylactic regimens are also probably indicated for non–HIV-infected patients at risk of P. jirovecii pneumonia.

Key Points
• Consider P. jirovecii pneumonia in patients who are immunosuppressed, even if they have mild respiratory symptoms and even if the chest x-ray is normal.
• Do histopathologic examination on induced sputum or bronchoscopically obtained sputum.
• Treat patients with trimethoprim/sulfamethoxazole, adding a corticosteroid if Pa o 2 is < 70 mm Hg.

CLINICAL VIGNETTES

While making rounds on the rehabilitation floor of your hospital, you see a 62-year-old female who was recently transferred from the acute-care section of the hospital where she was admitted for urosepsis. She is a liver-transplant recipient and her specialist has been tapering her immunosuppressive drug regimen for the last 2 months. According to the nursing staff the patient became hypoxic suddenly and had a low-grade fever and cough. You note that she looks ill and uncomfortable, and has an increased respiratory rate. A chest radiograph reveals diffuse bilateral interstitial infiltrates. Which one of the following is the most likely diagnosis?

A. Pneumococcal pneumonia
B. Staphylococcal pneumonia
C. Pneumocystis pneumonia
D. Pulmonary tuberculosis
E. Pneumothorax

ANSWER: C. The most likely diagnosis is Pneumocystis pneumonia. Initially named Pneumocystis carinii, the causative organism has been reclassified and renamed Pneumocystis jiroveci. It causes disease in immunocompromised patients. In non–HIV-infected patients, the most significant risk factors are defects in cell-mediated immunity, glucocorticoid therapy, use of immunosuppressive agents (especially when dosages are being lowered), hematopoietic stem cell or solid organ transplant, cancer, primary immunodeficiencies, and severe malnutrition.

The clinical presentation in patients without HIV/AIDS is typically an acute onset of hypoxia and respiratory failure, associated with a dry cough and fever. Characteristic radiographic findings include diffuse bilateral interstitial infiltrates.

Pneumococcal pneumonia typically presents with fever, chills, cough, and pleuritic chest pain. A sudden onset of severe hypoxia is less common. Radiologic findings typically include lobar infiltrates or bronchopneumonia (with a segmental pattern of infiltrate), whereas diffuse bilateral infiltrates are much less common. Staphylococcal pneumonia usually has radiologic findings of focal, multiple infiltrates or cavitary lesions.

Pulmonary tuberculosis presents most commonly with pleuritic or retrosternal chest pain. Fever is present in about 25% of patients. Cough is actually less common, and a sudden onset of acute hypoxia would be a very rare presentation. Radiographs typically reveal hilar adenopathy and pleural effusion. Diffuse bilateral interstitial infiltrates would be a very rare finding.

Spontaneous pneumothorax does present with an acute onset of hypoxia, tachypnea, and respiratory distress. However, fever would be unlikely and the radiologic findings in this patient are not consistent with pneumothorax.

A 71-year-old woman comes to the emergency department because of severe shortness of breath, retrosternal chest pain, a fever, and a dry cough that has worsened over the past three weeks. She blushes as she admits that she has many male "suitors". She does not smoke cigarettes. However, she drinks a "moderate" amount of alcohol each day. She recalls having an episode of fever, headaches, joint pain, a loss of appetite, and a mild sore throat a few months ago that she did not seek medical attention for because she assumed it was a "virus". Her temperature is 38.8 C (101.8 F) and respirations are 35/min. She has bibasilar rales and significant cervical, axillary, and inguinal lymphadenopathy. A chest x-ray shows bilateral patchy alveolar infiltrates. Histologic evaluation of a sputum sample obtained by bronchoalveolar lavage shows round structures when stained with methenamine silver. An important question to ask at this time is:

A. "Did you or your late husband ever install insulation or brake lining, do construction work, or work in a shipyard?"
B. "Do you engage in unprotected sexual intercourse at the present time or at any other time in the past?"
C. "Have you ever been involved in a homosexual relationship?"
D. "Have you ever had a morning drink to get started (an "eyeopener")?"
E. "Have you ever had a positive PPD or been exposed to anyone with tuberculosis?"

The correct answer is B. This patient most likely has Pneumocystis carinii pneumonia (PCP), and she is probably infected with the human immunodeficiency virus (HIV), in her case, most likely due to unprotected sexual intercourse with an infected individual. It is important to recognize that elderly patients may be sexually active, even if their spouse is no longer around. They are at risk for HIV and other sexually transmitted diseases because they may not think to use a condom because they are not worried about getting pregnant. PCP is characterized dyspnea, fever, a nonproductive cough, retrosternal chest pain, tachypnea, tachycardia, few abnormalities on auscultation, bilateral patchy alveolar infiltrates on chest x-ray, and round cysts found under light microscopy when stained with methenamine silver. The treatment is trimethoprim-sulfamethoxazole. The "episode of fever, headaches, joint pain, a loss of appetite, and mild sore throat" that she describes having a few months earlier is consistent with the acute HIV syndrome which affects many patients with HIV, approximately three to six weeks after the primary infection. This syndrome coincides with plasma viremia (wide dissemination of the virus). The symptoms gradually subside over a few weeks.

"Did you or your late husband ever install insulation or brake lining, do construction work, or work in a shipyard?" (choice A) is an important question if an asbestos-related disease is suspected, but this case is more consistent with Pneumocystis carinii pneumonia than asbestosis or malignant mesothelioma. Asbestosis is characterized by dyspnea, a nonproductive cough, basilar crackles or rales, clubbing, linear streaking and pleural thickening seen on chest x-ray, and ferruginous bodies seen on microscopic examination of lung tissue (rod-shaped bodies with clubbed ends). Malignant mesothelioma is a tumor of the pleura that is characterized by chest pain, dyspnea, a cough, a chest x-ray showing pleural fluid, irregular pleural thickening, and a biopsy demonstrating the malignant cells.

"Have you ever been involved in a homosexual relationship?" (choice C) is not a vital question at this time because it is very unlikely that this woman contracted HIV and AIDS from unprotected sexual intercourse with another woman. It is more likely that she contracted the infection from unprotected sexual intercourse with a man. Also, if you wanted to know if a patient has homosexual relationships, it is better to ask in a nonjudgmental way, such as, "Do you have sex with men, women, or both?"

"Have you ever had drink in the morning to get started (an "Eyeopener")?" (choice D) is a part of a four question screening test to detect problem drinking called the CAGE questionnaire. The other three questions that make up the CAGE questionnaire include: “Have you ever felt the need to Cut down on your drinking?”, “Have you ever felt Annoyed by criticisms of your drinking?”, and “Have you ever had Guilty feelings about drinking?”. Two positive responses indicate that a problem is likely. These questions may be important, but the immediate concern in this case is this patient's Pneumocystis carinii pneumonia and whether she has been infected with the HIV virus. Questions related to her sexual practices may help to identify the source of infection.

"Have you ever had a positive PPD or been exposed to anyone with tuberculosis?" (choice E) is a question that is important if tuberculosis or an aspergilloma is suspected. However, this case is more consistent with Pneumocystis carinii pneumonia. Primary tuberculosis (TB) is characterized by systemic symptoms, a cough, sputum production, hemoptysis, lower lobe infiltrates, hilar node enlargement, pleural involvement, and the presence of acid-fast bacilli. Reactivation TB is characterized by infiltrates with cavitation in the apices. An aspergilloma is a "fungus ball"' that typically forms within a preexisting cavity (from TB or sarcoidosis) in the pulmonary parenchyma. The patients may be asymptomatic or present with hemoptysis. A culture shows fungal mycelia, which appear as branching hyphae. In this case, microscopic evaluation shows round structures, not acid-fast bacilli or hyphae.

Four years ago a 30-year-old heroin addict who habitually used shared needles when taking the drug intravenously (IV) tested positive for the human immunodeficiency virus (HIV) by the enzyme- linked immunosorbent assay (ELISA) and then by a Western blot test. He now presents to the physician on duty at a community clinic with fever, dyspnea, tachypnea, and peripheral cyanosis. A chest x-ray film reveals extensive “ground-glass” opacities in the lower zones of both lungs. The physician would expect which of the following?

A. Organism response to amphotericin B
B. Organism response to erythromycin
C. Granulomas in the bone marrow
D. Organism response to trimethoprim–sulfamethoxazole
E. Gram’s stain of sputum to be diagnostic

The answer is D. The patient has a Pneumocystis carinii pneumonitis with the characteristic radiographic findings of “ground glass” opacities in the lungs. Methenamine silver stains (not Gram’s stain; choice E) of lung tissue or bronchoalveolar lavage specimens frequently demonstrate densely clustered cysts that resemble crushed ping- pong balls. Because the patient is human immunodeficiency virus (HIV) positive and has an opportunistic infection, the patient qualifies as having acquired immune deficiency syndrome (AIDS). P. carinii is the most common initial manifestation and cause of death in patients with AIDS. Once considered a protozoan, DNA analysis now shows that this organism is more closely related to a fungus; moreover, it cannot be cultured. Patients are generally susceptible to P. carinii infection when their CD4 helper T-cell count approaches 200 cells/mm3 and infection is contracted in immunosuppressed patients by inhalation, producing an inter- stitial pneumonitis with extreme hypoxia. P. carinii predominantly affects the lungs, but it can also involve other head and neck organs, such as the thyroid or the skin. The treatment for P. carinii is trimethoprim– sulfamethoxazole (TMP-SMX; choice D) or pentamidine. Aerosolized pentamidine or low-dose sulfonamides are useful as prophylaxis against the infection. There is a 20% fatality rate with each infection; there- fore, lifetime prophylaxis is needed. The infection does not respond to amphotericin B (choice A) or erythromycin (choice B). P. carinii is easily confused with Histoplasma capsulatum, but Histoplasma organisms are located in macrophages. Disseminated histoplasmosis could present with granulomas in the bone marrow (choice C). P. carinii does not produce granulomatous inflammation. Amphotericin B is the treatment of choice for histoplasmosis.
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Idiopathic Intracranial Hypertension
(Benign Intracranial Hypertension; Pseudotumor Cerebri)

Idiopathic intracranial hypertension causes increased intracranial pressure without a mass lesion or hydrocephalus, probably by obstructing venous drainage; CSF composition is normal.

Idiopathic intracranial hypertension typically occurs in women of childbearing age. Incidence is 1/100,000 in normal-weight women but 20/100,000 in obese women. Intracranial pressure is elevated (> 250 mm H 2 O); the cause is unknown but probably involves obstruction of cerebral venous outflow.

Symptoms and Signs

Almost all patients have a daily or near daily generalized headache of fluctuating intensity, at times with nausea. They may also have transient obscuration of vision, diplopia (due to 6th cranial nerve dysfunction), and pulsatile intracranial tinnitus. Vision loss begins peripherally and may not be noticed by patients until late in the course. Permanent vision loss is the most serious consequence.

Bilateral papilledema is common; a few patients have unilateral or no papilledema. In some asymptomatic patients, papilledema is discovered during routine ophthalmoscopic examination. Neurologic examination may detect partial 6th cranial nerve palsy but is otherwise unremarkable.

Diagnosis
• MRI with magnetic resonance venography
• Lumbar puncture

If clinical findings suggest idiopathic intracranial hypertension, clinicians should check visual fields and optic fundi, even in patients with no visual symptoms.

Diagnosis is suspected clinically and established by brain imaging (preferably MRI with magnetic resonance venography) that has normal results (except for venous transverse), followed by lumbar puncture with CSF testing that indicates elevated opening pressure and normal CSF composition.

Use of certain drugs and certain disorders can produce a clinical picture resembling idiopathic intracranial hypertension.

Treatment
• Acetazolamide
• Weight loss
• Drugs used for migraine, especially topiramate

Treatment is aimed at reducing pressure, preserving vision, and relieving symptoms. The carbonic anhydrase inhibitor acetazolamide (250 mg po qid) is used as a diuretic. Obese patients are encouraged to lose weight, which may help reduce intracranial pressure. Serial lumbar punctures are controversial but are sometimes used, particularly if, while waiting for definitive treatment, vision is threatened. Any potential causes (disorders or drugs) are corrected or eliminated if possible.

Drugs used for migraine (particularly topiramate, which also inhibits carbonic anhydrase) may relieve headache. NSAIDs can be used as needed.

If vision deteriorates despite treatment, optic nerve sheath fenestration, shunting (lumboperitoneal or ventriculoperitoneal), or endovascular venous stenting may be indicated. Bariatric surgery with sustained weight loss may cure the disorder in obese patients who were otherwise unable to lose weight.

Frequent ophthalmologic assessment (including quantitative visual fields) is required to monitor response to treatment; testing visual acuity is not sensitive enough to warn of impending vision loss.

Key Points
• Consider idiopathic intracranial hypertension if patients, particularly overweight women, have a daily generalized headache with or without visual symptoms; check visual fields and optic fundi.
• Diagnose based on results of brain imaging (preferably MRI with venography) and, if not contraindicated, lumbar puncture.
• Advise weight loss and treat with acetazolamide.
• Do frequent ophthalmologic assessments (including quantitative visual fields) to monitor response to treatment.

CLINICAL VIGNETTES

A moderately obese 14-year-old girl has a 2-week history of severe bifrontal headaches and early morning vomiting. She appears alert and is cooperative. She is right-handed. Her pulse is 82/min, and blood pressure is 112/76 mm Hg. Funduscopy shows papilledema. Her visual acuity is 20/20 bilaterally; neurologic examination and CT scan of the head show no abnormalities. Which of the following is the most likely diagnosis?

A. Migraine
B. Optic neuritis
C. Posterior fossa tumor
D. Pseudotumor cerebri
E. Tension headaches

A 17-year-old obese girl comes to the office because of a bifrontal, non-throbbing headache that has been worsening over the past 6 months. It often wakes her from sleep, but improves if she gets up and walks around. She also says that her vision is "not as good as it used to be," but cannot give you more details. Examination is significant for mild optic disk blurring. She went to the local emergency department 5 days earlier with similar complaints and an MRI of the head was performed and reported as normal. The most appropriate next step in managing this case is to

A. obtain an electroencephalogram
B. obtain a neurosurgical consult
C. perform a lumbar puncture
D. repeat the MRI of the head
E. start propranolol

The correct answer is C. The history and exam are typical for idiopathic intracranial hypertension (pseudotumor cerebri). The exact cause is unknown, but it is probably due to impaired reabsorption of cerebrospinal fluid leading to raised intracranial pressure. It usually occurs in obese, young women. Lumbar puncture shows an elevated opening pressure and normal CSF. Acetazolamide may be used to lower intracranial pressure. Weight reduction is important.

Obtaining an electroencephalogram (choice A) will not help with the diagnosis.

There is no reason for a neurosurgical consult (choice B).

Since nothing has changed since last week and she has the exact same symptoms, a repeat MRI of the head (choice D) is not indicated. It would be appropriate if she had different symptoms.

Propranolol (choice E) is used for migraine prophylaxis and is not indicated here, as this patient's condition is consistent with idiopathic intracranial hypertension, and further evaluation is indicated.

A 32-year-old white female presents with a 6-week history of increasing headache, which she now describes as severe. The only abnormal finding on examination is a BMI of 32.4 kg/m2. A neurologic examination is normal. CT of the head is normal and a lumbar puncture is remarkable only for increased cerebrospinal fluid pressure. There is no history of trauma or hypercoagulable disorder. Management should be directed toward preventing which one of the following?

A. Visual loss
B. Hearing loss
C. Vertigo
D. A cerebrovascular accident
E. Cerebral herniation

ANSWER: A. Loss of vision is a devastating neurologic deficit that occurs with idiopathic intracranial hypertension (pseudotumor cerebri, benign intracranial hypertension), although it is uncommon. Sixth cranial nerve palsies may also occur as a false localizing sign. The typical presentation is a young, obese woman with a headache, palpable tinnitus, and nausea and vomiting. CT is usually normal or shows small ventricles. The lumbar puncture shows elevated pressure with normal fluid examination. CSF protein levels may be low.
Hearing loss and vertigo are not characteristic of this disorder. Long tract signs and facial nerve palsies have been attributed to idiopathic intracranial hypertension; they are atypical and should lead to consideration of other diagnoses.
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Cushing syndrome is a constellation of clinical abnormalities caused by chronic high blood levels of cortisol or related corticosteroids. Cushing disease is Cushing syndrome that results from excess pituitary production of ACTH, usually secondary to a pituitary adenoma. Typical symptoms and signs include moon facies and truncal obesity, easy bruising, and thin arms and legs. Diagnosis is by history of receiving corticosteroids or by finding elevated serum cortisol. Treatment depends on the cause.

Etiology
Hyperfunction of the adrenal cortex can be ACTH dependent or ACTH independent.

ACTH-dependent hyperfunction may result from:
• Hypersecretion of ACTH by the pituitary gland
• Secretion of ACTH by a nonpituitary tumor, such as small cell carcinoma of the lung or a carcinoid tumor (ectopic ACTH syndrome)
• Administration of exogenous ACTH

ACTH-independent hyperfunction usually results from therapeutic administration of corticosteroids or from adrenal adenomas or carcinomas.

Whereas the term Cushing syndrome denotes the clinical picture resulting from cortisol excess from any cause, Cushing disease refers to hyperfunction of the adrenal cortex from pituitary ACTH excess. Patients with Cushing disease usually have a small adenoma of the pituitary gland.

Symptoms and Signs
Clinical manifestations include moon facies with a plethoric appearance, truncal obesity with prominent supraclavicular and dorsal cervical fat pads (buffalo hump), and, usually, very slender distal extremities and fingers. Muscle wasting and weakness are present. The skin is thin and atrophic, with poor wound healing and easy bruising. Purple striae may appear on the abdomen. Hypertension, renal calculi, osteoporosis, glucose intolerance, reduced resistance to infection, and mental disturbances are common. Cessation of linear growth is characteristic in children. Females usually have menstrual irregularities. In females with adrenal tumors, increased production of androgens may lead to hypertrichosis, temporal balding, and other signs of virilism.

Diagnosis
• Dexamethasone suppression test
• Midnight serum or salivary cortisol levels
• Urinary free cortisol (UFC) level
• ACTH levels; if detectable, provocative testing

Diagnosis is usually suspected based on the characteristic symptoms and signs. Confirmation (and identification of the cause) generally requires hormonal and imaging tests.

In some centers, testing begins with measurement of UFC, the best assay for urinary excretion (normal, 20 to 100 μg/24 h [55.2 to 276 nmol/24 h]). UFC is elevated > 120 μg/24 h (> 331 nmol/24 h) in almost all patients with Cushing syndrome. However, many patients with UFC elevations between 100 and 150 μg/24 h (276 and 414 nmol/24 h) have obesity, depression, or polycystic ovaries but not Cushing syndrome. A patient with suspected Cushing syndrome with grossly elevated UFC (> 4 times the upper limit of normal) almost certainly has Cushing syndrome.

An alternative approach to investigation uses the dexamethasone suppression test, in which 1, 1.5, or 2 mg of dexamethasone is given po at 11 to 12 pm and serum cortisol is measured at 8 to 9 am the next morning. In most normal patients, this drug suppresses morning serum cortisol to ≤ 1.8 μg/mL (≤ 50 nmol/L), whereas patients with Cushing syndrome virtually always have a higher level. A more specific but equally sensitive test is to give dexamethasone 0.5 mg po q 6 h for 2 days (low dose). In general, a clear failure to suppress cortisol levels in response to low-dose dexamethasone establishes the diagnosis.

ACTH levels are measured to determine the cause of Cushing syndrome. Undetectable levels, both basally and particularly in response to corticotropin-releasing hormone (CRH), suggest a primary adrenal cause. High levels suggest a pituitary cause.

Pituitary imaging is done if ACTH levels and provocative tests suggest a pituitary cause; gadolinium-enhanced MRI is most accurate, but some microadenomas are visible on CT. If testing suggests a nonpituitary cause, imaging includes high-resolution CT of the chest, and adrenals.

Treatment
• Metyrapone or ketoconazole
• Surgery or radiation therapy to remove tumors

Initially, the patient’s general condition should be supported by high protein intake and appropriate administration of K. If clinical manifestations are severe, it may be reasonable to block corticosteroid secretion with metyrapone 250 mg to 1 g po tid or ketoconazole 400 mg po once/day, increasing to a maximum of 400 mg tid. Ketoconazole is slower in onset, sometimes hepatotoxic, and its current availability is uncertain.

Pituitary tumors that produce excessive ACTH are removed surgically or extirpated with radiation therapy. If no tumor is shown on imaging but a pituitary source is likely, total hypophysectomy may be attempted, particularly in older patients.

Bilateral adrenalectomy is reserved for patients with pituitary hyperadrenocorticism who do not respond to both pituitary exploration (with possible adenomectomy) and irradiation. Adrenalectomy requires life-long corticosteroid replacement.

Adrenocortical tumors are removed surgically. Patients must receive cortisol during the surgical and postoperative periods because their nontumorous adrenal cortex will be atrophic and suppressed. Benign adenomas can be removed laparoscopically. With multinodular adrenal hyperplasia, bilateral adrenalectomy may be necessary. Even after a presumed total adrenalectomy, functional regrowth occurs in a few patients.

Ectopic ACTH syndrome is treated by removing the nonpituitary tumor that is producing the ACTH. However, in some cases, the tumor is disseminated and cannot be excised. Adrenal inhibitors, such as metyrapone 500 mg po tid (and up to a total of 6 g/day) or mitotane 0.5 g po once/day, increasing to a maximum of 3 to 4 g/day, usually control severe metabolic disturbances (eg, hypokalemia).
Key Points
• Diagnosis is usually made by elevated nocturnal serum or salivary cortisol levels, or 24-h urinary free cortisol, and a dexamethasone suppression test.
• Pituitary causes are distinguished from nonpituitary causes by ACTH levels.
• Imaging is then done to identify any causative tumor.
• Tumors are usually treated surgically or with radiation therapy.
• Metyrapone or ketoconazole may be given to suppress cortisol secretion prior to definitive treatment.

CLINICAL VIGNETTES

A 45-year-old woman has been followed for four visits for hypertension (blood pressure of 150 to 160/90 to 100) discovered during a routine examination, at which time, she was also found to have type 2 diabetes. Initially, an angiotensin-converting enzyme inhibitor failed to effect a fall in blood pressure from her baseline measurements. On the third visit, the blood pressure had responded to hydrochlorothiazide/ triamterene and her blood sugar had fallen to 120 to 130 at 2 hours postprandially as prescribed glipizide took effect. You notice that she is not only obese but also that her obesity is centripetal with proximal muscle wasting, associated with a plethoric face and purple striae about the trunk and that she complains of menstrual irregularity. She manifests also supra- clavicular fat pads. Which of the following is the most likely comprehensive clinical diagnosis?

A. Metabolic syndrome  |  B. Essential hypertension  |  C. Type 2 diabetes  
D. Cushing syndrome  |  E. Morbid obesity

The answer is D. Cushing syndrome is associated with and precipitates, if not causes, both hypertension and diabetes type 2. The purple striae are not specific for Cushing syndrome, as they are associated with recent and rapid development of obesity. However, Cushing syndrome brings with it not only recent and rapid obesity but also the protein catabolic aspects of the syndrome, and attendant weakening of protein structures allows a significantly lower threshold for development of the striae. The same may be said for the facial plethora but to a lesser degree. The metabolic syndrome is also associated with hypertension and diabetes type 2, but the purple striae and rubor are a virtual stigma of Cushing syndrome when seen with hypertension and diabetes. On occasion, in a primary care setting, a physician may encounter seemingly mysterious supraclavicular fat pads in a patient seen for unrelated reasons. In such cases, one needs to be mindful of the possibility of Cushing syndrome. Morbid obesity, weight equal to or exceeding 100 lb (45.3 kg) in excess of the ideal, would not explain proximal muscle wasting.

Regarding the patient in the previous question, which of the following tests will differentiate Cushing disease (Cushing syndrome caused by pituitary overproduction of ACTH) from Cushing syndrome caused by an ectopic source, primary adrenal disease, or extrinsic origin?

A. Serum cortisol test
B. 24-hour urine catecholamine test
C. Dexamethasone suppression test
D. Serum prolactin test
E. Melanocyte-stimulating hormone test

The answer is C. There are several levels of precision and sensitivity in the dexamethasone suppression tests. In Cushing disease, cortisol precursors and their metabolic by-products are responding to excessive production of ACTH by the anterior pituitary. In the overnight dexamethasone suppression test, the baseline plasma cortisol level is measured before administration of 1 mg of dexamethasone and should be suppressed to less than 50% of that value on the next morning. In addition, baseline ACTH is measured and expected to be similarly suppressed, and the same with 24-hour urine 17- hydroxycorticosteroids. Another version of the overnight dexamethasone suppression test employs administration of 1 mg of dexamethasone orally at 11 am and the collection of serum cortisol on the following morning at 8 am. A morning cortisol level of 􏰁5 􏰋g/dL by fluorometric assay or of 􏰁2 􏰋g/dL by high-performance liquid chromatography is 98% specific to rule out Cushing syndrome. Thus, cortisol was suppressible. This would not apply to Cushing disease caused by exogenous hydrocortisone (medication). Thus, Choice A, serum cortisol, is part (but only part) of the test. None of the other choices is relevant to this case.

A 42-year-old woman with a body metabolic index (BMI) of 42 kg/m2, who does not smoke, presents with diastolic hypertension and menstrual irregularities. Pertinent findings upon physical examination are a full, plethoric-appearing face, increased facial hair, pre- dominantly truncal obesity with purple stria around the abdomen, and scattered ecchymoses over the entire body. Laboratory studies indicate a hemoglobin (Hb) level of 18 g/dL (normal, 12–16 g/dL), a white blood cell (WBC) count of 18,000 cells/mm3 (normal, 4,500–11,000 cells/mm3), and a normal platelet count. The leukocyte differential shows an absolute neutrophilic leukocytosis and absolute lymphopenia and eosinopenia. Which of the following screening tests is most useful in the initial workup of this patient?

A. Captopril-enhanced renal radionuclide test 
B. Plasma cortisol at 8 AM and 4 PM
C. Clonidine suppression test
D. Bone marrow aspiration and biopsy
E. Low-dose dexamethasone suppression test

The answer is E. The patient has Cushing syndrome, which is a state of hypercortisolism. There are several causes. Iatrogenic Cushing syndrome, which occurs most commonly in a patient taking corticosteroids, is the major non- pathologic cause. Pituitary Cushing syndrome is the most common pathologic cause of Cushing syndrome (􏱹60% of cases). It is most often due to a benign pituitary adenoma secreting adrenocorticotropic hormone (ACTH). Adrenal Cushing syndrome and ectopic Cushing syndrome account for the remainder of causes of the syndrome. Adrenal Cushing syndrome is most often due to a benign adenoma secreting cortisol. The excess cortisol suppresses plasma ACTH. Ectopic Cushing syndrome is most often caused by a small-cell carcinoma of the lung with ectopic production of ACTH.

Clinical findings in Cushing syndrome are protean and parallel the excessive production of cortisol, weak mineralocorticoids (e.g., deoxycorticosterone), and 17-ketosteroids, which are weak androgens (e.g., dehydroepiandrosterone sulfate). Truncal obesity is a characteristic finding. Excess fat is distributed in the face (“moon face”), cervical area (“buffalo hump”), and abdomen, with sparing of the extremities. This peculiar distribution is due to the lipogenic effect of insulin, which is released in response to hyperglycemia caused by hypercortisolism (cortisol is a gluconeogenic hormone). Since most of the substrates for gluconeogenesis derive from amino acids, and amino acids are in abundance in muscle tissue, muscle catabolism is prominent in the arm and leg muscles. Wide purple striae are secondary to weak subcutaneous tissue and vessel instability, leading to ecchymoses and bleeding into the stretch marks. This tissue instability is the result of the inhibitory effect of cortisol on collagen synthesis. Hypertension in Cushing syndrome is associated with increased release of weak mineralocorticoids and subsequent retention of sodium. Hirsutism is due to an increased concentration of 17-ketosteroids, which are weak androgens. The plethoric face is due to vessel engorgement from secondary polycythemia induced by cortisol-enhanced erythropoiesis. Severe osteoporosis can result from cortisol’s potentiation of the effects of parathyroid hormone and vitamin D on bone. Menstrual irregularities (usually amenorrhea) and mental aberrations round out the clinical picture. Hypercortisolism has an effect on the leukocyte count. Cortisol decreases neutrophil adhesion to endothelial cells, resulting in a neutrophilic leukocytosis; increases adhesion of lymphocytes in efferent lymphatics, which produces lymphopenia; and is cytotoxic to eosinophils, causing eosinopenia.

Laboratory testing for pathologic causes of Cushing syndrome involves the use of screening tests to establish the diagnosis and other tests to determine the type of Cushing syndrome. After documenting an increased level of serum cortisol, most clinicians screen for Cushing syndrome with a low-dose (1 mg) dexamethasone (an analogue of cortisol) suppression test (choice E) to see if the high-baseline cortisol can be suppressed to less than 5 􏰋g/dL. Patients with pituitary, adrenal, and ectopic Cushing syndrome do not sup- press cortisol below 5 􏰋g/dL. False-positive results can occur in stressed patients and in obese patients. There is an increased false-positive loss of the normal diurnal rhythm of serum cortisol (high at 8 AM and low at 4 PM) in stressed or obese individuals; therefore, loss of a diurnal rhythm is not a useful screening test (choice B). Another excellent screening test is a 24-hour urine collection for free cortisol. This test, along with a low-dose dexamethasone suppression test, clearly confirms the presence of Cushing syndrome; however, they do not provide information as to the cause of the syndrome.

To determine the type of Cushing syndrome, the high-dose dexamethasone test (8 mg/day) has the highest specificity. Hypercortisolism in pituitary Cushing syndrome can be suppressed, whereas that associated with adrenal and ectopic Cushing syndrome cannot be suppressed. Plasma ACTH is also a useful study. Patients with adrenal Cushing syndrome have decreased levels, those with pituitary Cushing syndrome have normal to slightly increased levels, and patients with ectopic Cushing syndrome have extremely high concentrations.

A captopril-enhanced renal radionuclide test (choice A) is used to document renovascular hypertension, which is most commonly due to atherosclerosis of the renal artery in elderly men or fibromuscular hyperplasia of the renal artery in young to middle-aged women. Other than hypertension, renovascular hypertension has no other parallel signs and symptoms with Cushing syndrome. The clonidine suppression test (choice C) is used to confirm pheochromocytoma caused by a tumor secreting excess catecholamines. Clonidine is a centrally acting adrenergic drug that cannot suppress the excessive catecholamines associated with a pheochromocytoma. A pheochromocytoma presents with paroxysmal hypertension, drenching sweats, and excessive anxiety, findings that are not present in this patient. A bone marrow examination (choice D), ostensibly as a workup of polycythemia in this patient, is not indicated.
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Adnexal Torsion
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Adnexal torsion is twisting of the ovary and sometimes the fallopian tube, interrupting the arterial supply and causing ischemia.

Adnexal torsion is uncommon, occurring most often during reproductive years. It usually indicates an ovarian abnormality.

Risk factors include the following:

• Pregnancy
• Induction of ovulation
• Ovarian enlargement to > 4 cm (particularly by benign tumors)

Benign tumors are more likely to cause torsion than malignant ones. Torsion of normal adnexa, which is rare, is more common among children than adults.

Typically, one ovary is involved, but sometimes the fallopian tube is also involved. Adnexal torsion can cause peritonitis.

Symptoms and Signs

Torsion causes sudden, severe pelvic pain and sometimes nausea and vomiting. For days or occasionally weeks before the sudden pain, women may have intermittent, colicky pain, presumably resulting from intermittent torsion that spontaneously resolves. Cervical motion tenderness, a unilateral tender adnexal mass, and peritoneal signs are usually present.

Diagnosis

Color Doppler transvaginal ultrasonography

Adnexal torsion is suspected based on typical symptoms (ie, intermittent, severe pelvic pain) and unexplained peritoneal signs plus severe cervical motion tenderness or an adnexal mass. The pain may be unilateral.

Diagnosis is usually confirmed by color Doppler transvaginal ultrasonography.

Treatment

Surgery to salvage the ovary

If torsion is suspected or confirmed by ultrasonography, laparoscopy or laparotomy is done immediately to attempt to salvage the ovary and fallopian tube by untwisting them. Salpingo-oophorectomy is required for nonviable or necrotic tissue. If an ovarian cyst or mass is present and the ovary can be salvaged, cystectomy is done. Otherwise, oophorectomy is required.

CLINICAL VIGNETTES

A 22-year-old college student comes to the emergency department with a severe right lower quadrant pain. She says that the pain started approximately 6 hours ago and has progressively worsened. She has no significant medical problems and her only medication is oral contraceptive pills. She is sexually active with 1 partner, her boyfriend. Her last menstrual period was 2 weeks ago. Vital signs are: temperature 37.0 C (98.6 F), blood pressure 120/70 mm Hg, and pulse is 80/min. Abdominal examination is significant for focal tenderness in the right lower quadrant. Pelvic examination reveals exquisite tenderness in the right adnexa, a closed cervical os, and clear vaginal discharge. Laboratory studies show:

B-HCG  negative
Leukocyte 7300/mm3
Hg 14g/dl

The most likely etiology of this patient's symptoms is

A. acute appendicitis
B. diverticulitis
C. ovarian torsion
D. a ruptured ectopic pregnancy
E. a tuboovarian abscess

The correct answer is C. Ovarian torsion is the most likely cause of abdominal pain localized to the right adnexa in this patient. She has no significant medical problems and presents with an acute onset of right lower quadrant pain in the absence of fever or other laboratory signs of an infectious process. Ovarian torsion often occurs in the setting of other ovarian pathology such as a cyst or other lesions in the ovary that causes it to twist upon its vascular supply. Ovarian torsion is quickly diagnosed by ultrasonography of the pelvis with the demonstration of absence of flow to the ovary. This is an urgent diagnosis and surgery is required to restore blood flow.

Acute appendicitis (choice A) is not a likely cause of abdominal pain in this patient. Acute appendicitis is an infectious process that results from obstruction of the appendix (usually by a fecalith) and subsequent bacterial infection. It usually presents with right lower quadrant pain, fever, and leukocytosis. The presence of peritoneal signs such as rebound tenderness raises the suspicion for a ruptured appendix.

Diverticulitis (choice B) is not a likely cause of abdominal pain in this patient. Diverticulitis is an infectious process that typically affects older patients who have diverticulosis. This most often affects the sigmoid colon, although diverticulosis can occur anywhere in the colon. Signs and symptoms of diverticulitis include lower abdominal pain, fever, nausea, vomiting, and leukocytosis.

A ruptured ectopic pregnancy (choice D) is not a likely cause of abdominal pain in this patient. This diagnosis must be considered in any pregnant woman who presents with abdominal pain, vaginal bleeding, and symptoms of shock. It is a surgical emergency. This patient has a negative serum Beta-HCG, which rules out the possibility of an intrauterine or ectopic pregnancy.

A tuboovarian abscess (choice E) is not a likely cause of abdominal pain in this patient. A tuboovarian abscess is an advanced form of pelvic inflammatory disease most often caused by the spread of bacteria from the lower genital tract. The most common bacterial pathogens are anaerobic. Risk factors for pelvic inflammatory disease include those associated with an increased risk of contracting a sexually transmitted disease, early age of first sexual encounter, multiple sexual partners, history of sexually transmitted disease, and douching. In addition, women using IUDs are at increased risk for pelvic inflammatory disease and tuboovarian abscess. Symptoms of tuboovarian abscess include pelvic pain, fever, leukocytosis, and abnormal cervical or vaginal discharge in the setting of pelvic inflammatory disease.

A 24-year-old woman comes to the office complaining of 2 days of intermittent severe right lower quadrant pain. Initially, she was able to continue her work as a waitress, but now is afraid that another "bout of pain" will occur while she is at work. She feels a "heaviness" in her lower abdomen and has low-grade pain all the time. A few times a day the pain becomes severe in the right lower quadrant and then she may vomit. She has had no fever or chills, but has had a poor appetite secondary to the waves of nausea occurring when the pain became severe. She is otherwise healthy and has never been hospitalized or had surgery. She has never been sexually active and is not using any form of contraception. The patient also relates that she was evaluated in the emergency department last night, "although the pain became much better by the time I got to the hospital." She presents a piece of paper with laboratory values and urinary tests from her visit: hematocrit 39%, white blood cell count 11,400/mm3, platelet count 367,000/mm3, sodium 138 mEq/L, potassium 4.0 mEq/L, creatinine 1.0 mg/dL, SGOT 18 U/L, and SGPT 22 U/L. A urinalysis was negative for leukocyte esterase, nitrite, and red or white blood cells. A urine pregnancy test was negative. No diagnostic studies were performed in the emergency department. Her temperature is 37.5 C (99.5 F), blood pressure 130/70 mm Hg, pulse is 100/min, and respirations are 20/min. On physical examination, there is most likely to be

A. abdominal rebound tenderness and guarding
B. an adnexal mass
C. isolated tenderness at McBurney point
D. normal pelvic exam
E. vaginal bleeding

The correct answer is B. The patient's history of intermittent, unilateral pelvic pain that is associated with nausea during peak pain is classic for ovarian torsion. Although torsion has been reported in normal size ovaries, this will occur most often with an ovarian cyst approximately 5-6 centimeters in size. When the ovary has twisted and its blood supply is cut off, the patient experiences extreme pain and nausea. When it untwists, the symptoms remit. The patient's white blood cell count will often be mildly elevated. This diagnosis requires a high index of suspicion, a careful pelvic examination by the physician, and a low threshold to order a pelvic ultrasound. The presence of arterial flow to the ovary does not rule out this diagnosis as twisting of the ovary occurs intermittently. Laparoscopic ovarian cystectomy or oophorectomy is the treatment of choice.

The presence of rebound tenderness and guarding (choice A) are more often associated with a perforated viscus (ruptured ectopic pregnancy, ruptured appendix, perforated ulcer, hemoperitoneum).

Isolated tenderness at McBurney's point implies the presence of appendicitis (choice C). Although appendicitis can present nonspecifically with vague symptoms, the patient's cyclic waves of pain and nausea are more classic for ovarian torsion.

A normal pelvic exam is a rare possibility, but not typical for ovarian torsion (choice D).

Vaginal bleeding (choice E) is not associated with ovarian torsion, but may be a feature seen with ectopic pregnancy. This presentation is also a concern for an ectopic pregnancy, but the urine pregnancy test was normal.

A 31-year-old woman comes to the emergency department with midline abdominal pain that she reports is 10 out of 10 in severity on a pain scale, with 10 being the worst pain she has ever felt. The pain has been present for 1 hour. She has no past medical history and her last menstrual period was 1 day ago. Her only medication is oral contraceptive pills. She has no allergies. She had an uncomplicated pregnancy 3 years ago and had an uneventful normal vaginal delivery. Vital signs are: temperature 37 C (98.6 F), pulse 90/min, blood pressure 100/70 mm Hg, and respirations 15/min. Oxygen saturation is 96% on room air. Physical examination reveals a woman in obvious pain. There is left adnexal and midline pelvic pain on palpation. A urine pregnancy test is negative. Ultrasonography of the pelvis demonstrates an enlarged left ovary with decreased blood flow. The most likely complication of this finding is

A. fibroid degeneration
B. infertility
C. ovarian cancer
D. ovarian cysts
E. pelvic inflammatory disease

The correct answer is B. A young woman with acute pelvic pain localizing to one side is suspicious for ovarian torsion. Associated symptoms may include nausea and vomiting. The diagnosis was confirmed with endovaginal ultrasound demonstrating an edematous ovary with decreased venous and possibly, arterial flow. Complications of ovarian torsion include infection, peritonitis, sepsis, adhesions, chronic pelvic pain, and infertility due to the loss of the viability of the torsed ovary.

Fibroids (choice A) may degenerate over time as they outgrow their blood supply. Moreover, adventitial fibroids may be pedunculated and torse on their stalk. Pain from a degenerating fibroid is rare. Degenerating fibroids have no association with ovarian torsion.

Ovarian cancer (choice C) is not a complication of torsion. The typical presentation of ovarian cancer is diffuse carcinomatosis and abdominal mass or bowel obstruction. Ovarian cancers can enlarge the ovary and may predispose it to twisting on its vascular supply.

Ovarian cysts (choice D) are not a complication of torsion. Benign functional ovarian cysts can get quite large and may predispose a patient to torsion by causing the ovary to twist on its vascular supply.

Pelvic inflammatory disease (choice E) is not a complication of torsion. It is caused by organisms ascending to the upper female genital tract from the vagina and cervix. It most commonly is associated with Chlamydia trachomatis and Neisseria gonorrhoeae, but other organisms, and in many cases multiple organisms, have been isolated.
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Gonorrhea
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Gonorrhea is caused by the bacteria Neisseria gonorrhoeae. It typically infects epithelia of the urethra, cervix, rectum, pharynx, or eyes, causing irritation or pain and purulent discharge. Dissemination to skin and joints, which is uncommon, causes sores on the skin, fever, and migratory polyarthritis or pauciarticular septic arthritis. Diagnosis is by microscopy, culture, or nucleic acid amplification tests. Several oral or injectable antibiotics can be used, but drug resistance is an increasing problem.

N. gonorrhoeae is a gram-negative diplococcus that occurs only in humans and is almost always transmitted by sexual contact. Urethral and cervical infections are most common, but infection in the pharynx or rectum can occur after oral or anal intercourse, and conjunctivitis may follow contamination of the eye. After an episode of vaginal intercourse, likelihood of transmission from women to men is about 20%, but from men to women, it may be higher. Neonates can acquire conjunctival infection during passage through the birth canal, and children may acquire gonorrhea as a result of sexual abuse.

In 10 to 20% of women, cervical infection ascends via the endometrium to the fallopian tubes (salpingitis) and pelvic peritoneum, causing pelvic inflammatory disease. Chlamydiae or intestinal bacteria may also cause PID. Gonorrheal cervicitis is commonly accompanied by dysuria or inflammation of Skene ducts and Bartholin glands. In a small fraction of men, ascending urethritis progresses to epididymitis. Disseminated gonococcal infection (DGI) due to hematogenous spread occurs in < 1% of cases, predominantly in women. DGI typically affects the skin, tendon sheaths, and joints. Pericarditis, endocarditis, meningitis, and perihepatitis occur rarely.

Coinfection with Chlamydia trachomatis occurs in 15 to 25% of infected heterosexual men and 35 to 50% of women.

Symptoms and Signs

About 10 to 20% of infected women and very few infected men are asymptomatic. About 25% of men have minimal symptoms.

Male urethritis has an incubation period from 2 to 14 days. Onset is usually marked by mild discomfort in the urethra, followed by more severe penile tenderness and pain, dysuria, and a purulent discharge. Urinary frequency and urgency may develop as the infection spreads to the posterior urethra. Examination detects a purulent, yellow-green urethral discharge, and the meatus may be inflamed.

Epididymitis usually causes unilateral scrotal pain, tenderness, and swelling. Rarely, men develop abscesses of Tyson and Littre glands, periurethral abscesses, or infection of Cowper glands, the prostate, or the seminal vesicles.

Cervicitis usually has an incubation period of > 10 days. Symptoms range from mild to severe and include dysuria and vaginal discharge. During pelvic examination, clinicians may note a mucopurulent or purulent cervical discharge, and the cervical os may be red and bleed easily when touched with the speculum. Urethritis may occur concurrently; pus may be expressed from the urethra when the symphysis pubis is pressed or from Skene ducts or Bartholin glands. Rarely, infections in sexually abused prepubertal girls cause dysuria, purulent vaginal discharge, and vulvar irritation, erythema, and edema.

PID occurs in 10 to 20% of infected women. PID may include salpingitis, pelvic peritonitis, and pelvic abscesses and may cause lower abdominal discomfort (typically bilateral), dyspareunia, and marked tenderness on palpation of the abdomen, adnexa, or cervix.

Disseminated gonococcal infection (DGI) , also called the arthritis-dermatitis syndrome, reflects bacteremia and typically manifests with fever, migratory pain or joint swelling (polyarthritis), and pustular skin lesions. In some patients, pain develops and tendons (eg, at the wrist or ankle) redden or swell. Skin lesions occur typically on the arms or legs, have a red base, and are small, slightly painful, and often pustular. Genital gonorrhea, the usual source of disseminated infection, may be asymptomatic. DGI can mimic other disorders that cause fever, skin lesions, and polyarthritis (eg, the prodrome of hepatitis B infection or meningococcemia); some of these other disorders also cause genital symptoms.

Gonococcal septic arthritis is a more localized form of DGI that results in a painful arthritis with effusion, usually of 1 or 2 large joints such as the knees, ankles, wrists, or elbows. Some patients present with or have a history of skin lesions of DGI. Onset is often acute, usually with fever, severe joint pain, and limitation of movement. Infected joints are swollen, and the overlying skin may be warm and red.

Diagnosis
• Gram staining and culture
• Nucleic acid–based testing

Gonorrhea is diagnosed when gonococci are detected via microscopic examination using Gram stain, culture, or a nucleic acid–based test of genital fluids, blood, or joint fluids (obtained by needle aspiration).

Gram stain is sensitive and specific for gonorrhea in men with urethral discharge; gram-negative intracellular diplococci typically are seen. Gram stain is much less accurate for infections of the cervix, pharynx, and rectum and is not recommended for diagnosis at these sites.

Culture is sensitive and specific, but because gonococci are fragile and fastidious, samples taken using a swab need to be rapidly plated on an appropriate medium (eg, modified Thayer-Martin) and transported to the laboratory in a CO 2 -containing environment. Blood and joint fluid samples should be sent to the laboratory with notification that gonococcal infection is suspected. Because nucleic acid amplification tests (NAAT) have replaced culture in most laboratories, finding a laboratory that can provide culture and sensitivity testing may be difficult and require consultation with a public health or infectious disease specialist.

Unamplified nucleic acid–based tests may be done on genital, rectal, or oral swabs. Most tests simultaneously detect gonorrhea and chlamydial infection and then differentiate between them in a subsequent specific test. Nucleic acid amplification tests (NAAT) further increase the sensitivity adequately to enable testing of urine samples in both sexes.

In the US, confirmed cases of gonorrhea, chlamydial infection, and syphilis must be reported to the public health system. Serologic tests for syphilis (STS) and HIV and NAAT to screen for chlamydial infection should also be done.

Men with urethritis

Men with obvious discharge may be treated presumptively if likelihood of follow-up is questionable or if clinic-based diagnostic tools are not available. Samples for Gram staining can be obtained by touching a swab or slide to the end of the penis to collect discharge. Gram stain does not identify chlamydiae, so urine or swab samples for NAAT are obtained.

Women with genital symptoms or signs

A cervical swab should be sent for culture or nucleic acid–based testing. If a pelvic examination is not possible, NAAT of a urine sample can detect gonococcal (and chlamydial) infections rapidly and reliably.

Pharyngeal or rectal exposures (either sex)

Swabs of the affected area are sent for culture or nucleic acid–based tests.

Arthritis, DGI, or both

An affected joint should be aspirated, and fluid should be sent for culture and routine analysis. Patients with skin lesions, systemic symptoms, or both should have blood, urethral, cervical, and rectal cultures or NAAT. In about 30 to 40% of patients with DGI, blood cultures are positive during the first week of illness. With gonococcal arthritis, blood cultures are less often positive, but cultures of joint fluids are usually positive. Joint fluid is usually cloudy to purulent because of large numbers of WBCs (typically > 20,000/μL).

Treatment

• For uncomplicated infection, a single dose of ceftriaxone plus azithromycin or doxycycline
• For DGI with arthritis, a longer course of parenteral antibiotics
• Concomitant treatment for chlamydial infection
• Treatment of sex partners

Uncomplicated gonococcal infection of the urethra, cervix, rectum, and pharynx is treated with a single dose of ceftriaxone 250 mg IM plus azithromycin 1 g po once or doxycycline 100 mg po bid for 7 days. Azithromycin or doxycycline is given to treat coinfection with chlamydiae and possibly to slow development of resistance to ceftriaxone. Monotherapy and previous oral regimens of fluoroquinolones (eg, ciprofloxacin, levofloxacin, ofloxacin) or cefixime are no longer recommended because of increasing drug resistance.

DGI with gonococcal arthritis is initially treated with IM or IV antibiotics (eg, ceftriaxone 1 g IM or IV q 24 h, ceftizoxime 1 g IV q 8 h, cefotaxime 1 g IV q 8 h) continued for 24 to 48 h once symptoms lessen, followed by 4 to 7 days of oral therapy. Antichlamydial therapy is also routinely given.

Gonococcal arthritis does not usually require joint drainage. Initially, the joint is immobilized in a functional position. Passive range-of-motion exercises should be started as soon as patients can tolerate them. Once pain subsides, more active exercises, with stretching and muscle strengthening, should begin. Over 95% of patients treated for gonococcal arthritis recover complete joint function. Because sterile joint fluid accumulations (effusions) may persist for prolonged periods, an anti-inflammatory drug may be beneficial.

Sex partners

All sex partners who have had sexual contact with the patient within 60 days should be tested for gonorrhea and other STDs and treated if results are positive. Sex partners with contact within 2 wk should be treated presumptively for gonorrhea (epidemiologic treatment).

Key Points
• Gonorrhea typically causes uncomplicated infection of the urethra, cervix, rectum, pharynx, and/or eyes.
• Sometimes gonorrhea spreads to the adnexa, causing salpingitis, or disseminates to skin and/or joints, causing skin sores or septic arthritis.
• Diagnose using NAAT, but culture and sensitivity testing should be done when needed to detect antimicrobial resistance.
• Screen asymptomatic, high-risk patients using NAAT.
• Treat uncomplicated infection with a single dose of ceftriaxone 250 mg IM plus either azithromycin 1 g po once or doxycycline 100 mg po bid for 7 days.

CLINICAL VIGNETTES

An 18-year-old girl comes to the clinic because of a 3-day history of vaginal discharge. The discharge is malodorous & has a greenish-yellow color. She admits to sexual intercourse with a "random guy at a fraternity party" 5 days earlier. Physical examination shows a malodorous, purulent vaginal discharge. Complete physical & pelvic examinations are unremarkable. A Gram stain of the discharge shows Gram-negative diplococci within polymorphonuclear leukocytes. Culture on a chocolate agar confirms the diagnosis. The most appropriate next step is to

A. admit her to the hospital for intravenous therapy with cefotetan
B. contact the board of health to report a case of gonorrhea
C. contact the "random guy at a fraternity party" and provide treatment and counseling
D. give her a single dose of ceftriaxone, intramuscularly and a single dose of azithromycin, orally
E. prescribe metronidazole for this patient and her sexual partner

The correct answer is D. This patient has a gonococcal infection and should be treated with a single dose of ceftriaxone, intramuscularly and a single dose of azithromycin, orally. The ceftriaxone treats the gonococcal infection and the azithromycin is added for the presumptive treatment of Chlamydia trachomatis. This is because many patients have co-existing infections. After treating the patient, this case should be reported to the board of health because gonorrhea is a notifiable infectious disease. Sexual contacts should be treated and counseled.

It is unnecessary to admit her to the hospital for intravenous therapy with cefotetan (choice A). This is part of the treatment of pelvic inflammatory disease, which is a disease of the upper genital tract. Patients often have cervical motion tenderness, lower abdominal tenderness, and adnexal tenderness, fever, cervical discharge, and laboratory documentation of N. Gonorrhea and/or C. trachomatis. These patients are treated with a cephalosporin for gonorrhea and doxycycline for chlamydia. This patient seems to have an uncomplicated gonococcal infection that can be treated as an outpatient.

Since gonorrhea is a notifiable disease, it is necessary to contact the board of health to report a case of gonorrhea (choice B) after treating the patient with the appropriate antibiotics.

The "random guy at a fraternity party" should be contacted to provide treatment and counseling (choice C) after treating the patient with the appropriate antibiotics.

It is incorrect to prescribe metronidazole for this patient and her sexual partner (choice E) because this is the treatment for Trichomonas vaginalis, not gonorrhea. Trichomonas vaginalis often presents with a frothy vaginal discharge. A wet mount shows motile flagellated organisms. Gram-negative diplococci within polymorphonuclear leukocytes are not found in this infection.

A 25-year-old man presents with complaints of dysuria for the past 6 days. He has had multiple female sexual partners in the past 2 months. Physical examination shows a yellowish penile discharge with inguinal adenopathy but no genital ulcers. Gram’s stain of the discharge shows intracellular gram-negative diplococci in leukocytes. Which one of the follow- ing should be used in the treatment of this patient?

A. Ceftriaxone
B. Ciprofloxacin
C. Procaine penicillin
D. Ceftriaxone plus doxycycline 
E. Doxycycline

The answer is D. This patient has gonococcal urethritis (GCU), which is caused by Neisseria gonorrhoeae. GCU is more common among homosexual men and those of the lower socioeconomic strata. Nongonococcal urethritis (NGU) on the other hand, is more commonly encountered in heterosexual males and those of higher socioeconomic class. NGU is twice as common as gonococcal urethritis in the United States; it is the most common sexually transmitted disease (STD) in men and is usually due to Chlamydia trachomatis. However, Trichomonas vaginalis or herpes simplex virus (HSV) can also cause NGU. At one time, the standard treatment would have been penicillin (choice C). However, because of increasing resistance, penicillin is no longer recommended for gonorrhea. Ceftriaxone (choice A) and cefixime are drugs that inhibit cell wall synthesis and are not susceptible to 􏰅-lactase hydrolysis; therefore, they are recommended replacements for penicillin in the treatment of gonorrhea. The quinolones, ciprofloxacin (choice B) and ofloxacin, inhibit bacterial DNA gyrase and have a relatively broad spectrum of activity. They too are effective against gonorrhea. However, because chlamydi- al infections so often accompany gonococcal infections, the Centers for Disease Control (CDC) recommends

that all patients with suspected or proved gonococcal urethritis also be treated as if they had chlamydial NGU. Although the quinolones have antichlamydial activity in vitro, they have not been recommended for clinical infections. C. trachomatis is susceptible to tetracyclines such as doxycycline (choice E), but strains of tetracy- cline-resistant N. gonorrhoeae have also become too common to recommend its use. Therefore, combined therapy, such as ceftriaxone and doxycycline (choice D), is required to treat both infections. Alternatively, because both organisms are still susceptible to the relatively new drug azithromycin, it can be used alone.
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A veteran suffering from Post-Traumatic Stress Disorder will file a lawsuit against the Atlanta VA Medical Center for prescribing him in December the drug Trazadone, which is an anti-depressant. The medication worked, but it had an unexpected side effect that Edward Stalling found "hard" to forget.
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Renal Artery Stenosis
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Renal artery stenosis is a decrease in blood flow through one or both of the main renal arteries or their branches. Renal artery occlusion is a complete blockage of blood flow through one or both of the main renal arteries or its branches. Stenosis and occlusion are usually due to thromboemboli, atherosclerosis, or fibromuscular dysplasia. Symptoms of acute occlusion include steady, aching flank pain, abdominal pain, fever, nausea, vomiting, and hematuria. Acute kidney injury may develop. Chronic, progressive stenosis causes refractory hypertension and may lead to chronic kidney disease. Diagnosis is by imaging tests (eg, CT angiography, magnetic resonance angiography). Treatment of acute occlusion is with anticoagulation and sometimes fibrinolytics and surgical or catheter-based embolectomy, or a combination. Treatment of chronic, progressive stenosis includes angioplasty with stenting, surgical bypass, and removal of an infarcted kidney.

Renal hypoperfusion results in hypertension, renal failure, and, if complete occlusion occurs, renal infarction and necrosis.

Etiology

Occlusion may be acute or chronic. Acute occlusion is usually unilateral. Chronic occlusion may be unilateral or bilateral.

Acute renal artery occlusion

The most common cause is thromboembolism. Emboli may originate in the heart (due to atrial fibrillation, after MI, or from vegetations due to bacterial endocarditis) or the aorta (as atheroemboli); less often, fat or tumor emboli are the cause. Thrombosis may occur in a renal artery spontaneously or after trauma, surgery, angiography, or angioplasty. Other causes of acute occlusion include dissection or rupture of a renal artery aneurysm.

Rapid, total occlusion of large renal arteries for 30 to 60 min results in infarction. The infarct is typically wedge-shaped, radiating outward from the affected vessel.

Chronic progressive renal artery stenosis

About 90% of cases are due to atherosclerosis, which is usually bilateral. Almost 10% of cases are due to fibromuscular dysplasia (FMD), which is commonly unilateral. Less than 1% of cases result from Takayasu arteritis, Kawasaki disease, neurofibromatosis type 1, aortic wall hematoma, or aortic dissection.

Atherosclerosis develops primarily in patients > 50 (more often men) and usually affects the aortic orifice or proximal segment of the renal artery. Chronic progressive stenosis tends to become clinically evident after about 10 yr of atherosclerosis, causing renal atrophy and chronic kidney disease.

FMD is pathologic thickening of the arterial wall, most often of the distal main renal artery or the intrarenal branches. The thickening tends to be irregular and can involve any layer (but most often the media). This disorder develops primarily in younger adults, particularly in women aged 20 to 50. It is more common among 1st-degree relatives of patients with FMD and among people with the ACE1 gene.


Symptoms and Signs

Manifestations depend on rapidity of onset, extent, whether unilateral or bilateral, and duration of renal hypoperfusion. Stenosis of one renal artery is often asymptomatic for a considerable time.

Acute complete occlusion of one or both renal arteries causes steady and aching flank pain, abdominal pain, fever, nausea, and vomiting. Gross hematuria, oliguria, or anuria may occur; hypertension is rare. After 24 h, symptoms and signs of acute kidney injury may develop. If the cause was thromboembolic, features of thromboembolism at other sites (eg, blue toes, livedo reticularis, retinal lesions on funduscopic examination) also may be present.

Chronic progressive stenosis causes hypertension, which may begin at an atypical age (eg, < 30 yr or after age 50 yr) and which may be refractory to control despite use of multiple antihypertensives. Physical examination may detect an abdominal bruit or signs of atherosclerosis. Symptoms and signs of chronic kidney disease develop slowly.

Diagnosis
• Clinical suspicion
• Imaging

Diagnosis is suspected in patients with renal failure and who have

• Symptoms of acute renal artery occlusion
• Symptoms or signs of thromboembolism

Hypertension that begins before age 30 or is refractory to treatment with > 3 antihypertensive drugs

Blood and urine tests are done to confirm renal failure. Diagnosis is confirmed by imaging tests. Which tests are done depends on the patient’s renal function and other characteristics and on test availability.

Some tests (CT angiography, arteriography, digital subtraction angiography) require an IV ionic radiocontrast agent, which may be nephrotoxic; this risk is lower with the nonionic hypo-osmolar or iso-osmolar contrast agents that are now in widespread use. Magnetic resonance angiography (MRA) requires the use of gadolinium contrast; in patients with severe chronic kidney disease, gadolinium contrast carries the risk of nephrogenic systemic fibrosis, a condition that closely resembles systemic sclerosis and that has no satisfactory method of treatment.

When results of other tests are inconclusive or negative but clinical suspicion is strong, arteriography is necessary for definitive diagnosis. Arteriography may also be needed before invasive interventions.

When a thromboembolic disorder is suspected, ECG (to detect atrial fibrillation) and hypercoagulability studies may be needed to identify treatable embolic sources. Transesophageal echocardiography is done to detect atheromatous lesions in the ascending and thoracic aorta and cardiac sources of thrombi or valvular vegetations.

Blood and urine tests are nondiagnostic but are done to confirm renal failure, indicated by elevated creatinine and BUN and by hyperkalemia. Leukocytosis, gross or microscopic hematuria, and proteinuria may also be present.

Treatment

Acute renal artery occlusion

A renal thromboembolic disorder may be treated with a combination of anticoagulation, fibrinolytics, and surgical or catheter-based embolectomy. Treatment within 3 h of symptom onset is likely to improve renal function. However, complete recovery is unusual, and early and late mortality rates are high because of extrarenal embolization or underlying atherosclerotic heart disease.

Patients presenting within 3 h may benefit from fibrinolytic (thrombolytic) therapy (eg, streptokinase, alteplase) given IV or by local intra-arterial infusion. However, such rapid diagnosis and treatment are rare.

All patients with a thromboembolic disorder require anticoagulation with IV heparin, unless contraindicated. Long-term anticoagulation with oral warfarin can be initiated simultaneously with heparin if no invasive intervention is planned. Anticoagulation should be continued for at least 6 to 12 mo—indefinitely for patients with a recurrent thromboembolic disorder or a hypercoagulability disorder.

Surgery to restore vascular patency has a higher mortality rate than fibrinolytic therapy and has no advantage in recovery of renal function. However, surgery, particularly if done within the first few hours, is preferred for patients with traumatic renal artery thrombosis. If patients with nontraumatic, severe renal failure do not recover function after 4 to 6 wk of drug therapy, surgical revascularization (embolectomy) can be considered, but it helps only a few.

If the cause is thromboemboli, the source should be identified and treated appropriately.

Chronic progressive renal artery stenosis

Treatment is indicated for patients who meet one or more of the following 5 criteria:

• Hypertension refractory to medical treatment with ≥ 3 drugs
• Deterioration of renal function despite optimal medical therapy
• A short duration of BP elevation prior to the diagnosis of renovascular disease
• Recurrent flash pulmonary edema
• Unexplained rapid progression of renal insufficiency

Treatment is with percutaneous transluminal angioplasty (PTA) plus stent placement or with surgical bypass of the stenotic segment. Usually, an extensively infarcted kidney must be removed if revascularization is not expected to result in functional recovery. Surgery is usually more effective than PTA for atherosclerotic occlusion; it cures or attenuates hypertension in 60 to 70% of patients. However, surgery is considered only if patients have complex anatomic lesions or if PTA is unsuccessful, particularly with repeated in-stent restenosis. PTA is preferred for FMD; risk is minimal, success rate is high, and restenosis rate is low.

Renovascular hypertension

Treatments are typically ineffective unless vascular patency is restored. ACE inhibitors, angiotensin II receptor blockers, or renin inhibitors can be used in unilateral and, if GFR is monitored closely, in bilateral renal artery stenosis. These drugs can reduce GFR and increase serum BUN and creatinine levels. If GFR decreases enough to increase serum creatinine, Ca channel blockers (eg, amlodipine, felodipine) or vasodilators (eg, hydralazine, minoxidil) should be added or substituted.

Key Points
• Renal artery stenosis or occlusion may be acute (usually due to thromboembolism) or chronic (usually due to atherosclerosis or fibromuscular dysplasia).
• Suspect acute occlusion if patients have steady, aching flank or abdominal pain, and sometimes fever, nausea and vomiting, and/or gross hematuria.
• Suspect chronic occlusion in patients who develop unexplained severe or early-onset hypertension.
• Confirm the diagnosis with vascular imaging.
• Restore vascular patency for patients who have acute occlusion and for selected patients (eg, with severe complications or refractory disease) who have chronic occlusion.
• Hypertension is difficult to control until vascular patency is restored, but begin treatment with ACE inhibitors, angiotensin II receptor blockers, or renin inhibitors; closely monitor GFR; and substitute Ca channel blockers or vasodilators if GFR decreases.

CLINICAL VIGNETTES

A 67-year-old man who had been successfully medicated for hypertension for the past 15 years develops a diastolic pressure of 110 mm Hg. At that time, he was taking hydrochlorothiazide, acebutolol, clonidine, and doxazosin mesylate for his blood pressure and metformin for type 2 diabetes. A serum panel was unremarkable, except that his creatinine level was 4 mg/dL (normal, 0.6–1.2 mg/dL), and his blood urea nitrogen (BUN) was 28 mg/dL (normal, 8–20 mg/dL). In an attempt to lower his blood pressure, his physician added enalapril; the patient rapidly developed renal failure. Which of the following choices represents the most likely diagnosis?

A. Renal arterial stenosis due to fibromuscular dysplasia
B. Acute renal artery occlusion
C. Renal vein thrombosis due to a malignant occlusion
D. Malignant hypertension
E. Renal arterial stenosis due to occlusive arteriosclerotic disease

The answer is E. In the general population, fewer than 5% of the cases of hypertension result from renal arterial occlusion. However, renovascular occlusion accounts for 70% of the cases of hypertension in patients over the age of 60 who have a diastolic blood pressure above 105 mm Hg and a serum creatine value above 2 mg/dL; moreover 80% to 90% of these cases are due to occlusive arteriosclerotic disease (choice E). If both kidneys are occluded, provision of an angiotensin-converting enzyme (ACE) inhibitor, such as enalapril, tends to provoke acute renal failure because the ACE inhibitor decreases angiotensin II production, which is required for effective renal circulation. This is noted on renal function tests by a rising creatinine level.

About 10% to 15% of the cases of renal arterial stenosis are due to fibromuscular dysplasia (choice A); renal stenosis is almost unique among the renal diseases in that it is not accompanied by proteinuria, since the glomerulus is intact and renal arterial pressure is decreased. However, these cases primarily occur in females who are between the ages of 30 and 50 years. Renal vein thrombosis due to a malignant occlusion (choice C) presents with severe back pain and hyperproteinuria. Symptoms of malignant hypertension (choice D) include rapid and extreme increase in systolic blood pressure (over 200 mm Hg), blurred vision, headache, shortness of breath, chest pain, proteinuria, and sometimes seizures. Such an acute attack occa- sionally occurs for no apparent reason, usually in a person who was being treated for hypertension. It is the extreme increase in systolic pressure that induces the other symptoms, which will get worse the longer the pressure remains elevated. Consequently, this is a medical emergency; the pressure must be reduced imme- diately, usually by IV administration of antihypertensive agents.

Even though an arthrosclerotic artery is more readily occluded than a healthy one, by definition acute renal artery occlusion (choice B) differs from occlusion due to stenosis in that the latter is a chronic event. However, other difference between an acute occlusion and an occlusion due to stenosis are that the acute occlusion generally is unilateral, whereas stenosis is bilateral 70% of the time, and acute occlusion presents with backache and blood in the urine, whereas stenosis presents with hypertension. An occlusion generally occurs after major surgery or trauma affecting the abdomen or side or in individuals with atrial fibrillation or mitral or valve disease.

A 21-year-old man has been found to be hypertensive with bilateral arm blood pressures in the 140-160/100-110 mm Hg range on several visits. The patient has no past medical history and has no complaints. Review of systems is significant for occasional “band-like headaches". Physical examination is normal including a normal retinal examination. Urinalysis is normal. An electrocardiogram demonstrates normal sinus rhythms at a rate of 75/min, with mild left ventricular hypertrophy. His blood pressure is now 150/100 mm Hg after treatment with maximal doses of atenolol, hydrochlorothiazide, and captopril. The next step in the evaluation of this patient's hypertension is to

A. order a duplex ultrasound of the renal arteries
B. order an echocardiogram
C. prescribe triamterene
D. repeat the electrocardiogram

The correct answer is A. This patient should be suspected of having renal artery stenosis, most likely secondary to fibromuscular dysplasia from the early age of onset of severe hypertension. In addition, the poor control of this patient's hypertension, even with three agents is suspicious for renovascular hypertension. About 5% of patients with hypertension have renovascular hypertension. The renal arteries need to be evaluated by duplex ultrasound of the renal arteries, conventional angiography, spiral computed tomography, or magnetic resonance angiography.

Given signs of left ventricular hypertrophy on electrocardiogram, echocardiography (choice B) is warranted. The next immediate step however, is an evaluation of the renal arteries.

Triamterene (choice C) is a potassium-sparing diuretic often used in conjunction with hydrochlorothiazide. It is very unlikely that the three agents prescribed in high doses could not control the blood pressure of a patient with essential hypertension. Renovascular hypertension must be suspected.

Repeat electrocardiograms (choice D) should be performed every year to evaluate for the development of end-organ damage in a chronic hypertensive. This patient has electrocardiographic evidence of left ventricular hypertrophy. However, it is best followed with echocardiography.

A 29-year-old woman has become hypertensive and BP levels are difficult to control. You have her on 10 mg lisinopril twice daily, hydrochlorthiazide/triamterene once daily, and 80 mg verapamil 3 times daily. BP levels run 160/105 despite the foregoing. Serum potassium was normal before therapy was started. The 24-hour urine studies for VMA, metanephrine, and free catecholamines were within normal limits. Which of the following may be helpful in further elucidating the diagnosis?

A. EKG
B. Liver function profile 
C. Lipid screen
D. Abdominal examination 
E. Complete blood count

The answer is D. The patient should be examined for an abdominal bruit, specifically a bruit deep in one flank that could be generated by renal artery stenosis. Essential hypertension, be it volume dependent or based more on peripheral vascular resistance, usually has its clinical onset in a person’s late 30s or 40s. Hypertension significantly earlier or that which comes on after a person reaches the age of 60 must be evaluated for other causes, of which renovascular type is one. When a person is at a younger age, the cause is most likely due to a congenital fibrous band, which has a 2:1 female-to-male occurrence ratio. After a person reaches the age of 60, the cause is more likely an atherosclerotic one, which has a 2:1 male-to- female occurrence ratio. None of the other choices has any specific relevance to the diagnosis of the pathophysiology of hypertension.
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