Abstract :
PRESENTING FEATURES: A 57-year-old white man with a history of human immunodeficiency virus (HIV) infection was admitted to the Osler Medical Service with 4 weeks of low-grade fevers, crampy abdominal pain, and voluminous diarrhea. He noted five to six stools a day, complained of nausea and occasional vomiting, and had decreased oral intake over the 3 days prior to admission. The diarrhea did not improve with fasting. There was no melena, hematochezia, or steatorrhea. He denied recent travel or ill contacts. His medications included trimethoprim-sulfamethoxazole and azithromycin, and he had never taken antiretroviral therapy.
On physical examination, the patient was lethargic, with a blood pressure of 92/52 mm Hg, a pulse rate of 118 beats per minute, and a respiratory rate of 16 breaths per minute. He was afebrile, his mucous membranes were dry, and his jugular venous pressure was not elevated. He had shotty cervical, axillary, and inguinal lymphadenopathy. Cardiovascular examination showed tachycardia, normal heart sounds, and no murmurs. Chest examination was unrevealing. On examination, the abdomen was soft and nontender, with hyperactive bowel sounds. There was no organomegaly. The stool was heme-negative. His extremities showed no edema, and the neurologic examination was nonfocal.
Laboratory values were notable for a CD4 count of 25 cells/mm3. White blood cell count was 4.0 × 103/μL, and the hemoglobin level was 10.6 g/dL. The serum potassium level was 1.8 mEq/L, blood urea nitrogen level was 57 mg/dL, and creatinine level was 1.5 mg/dL. Stool studies showed negative results for fecal leukocytes and occult blood. Results of blood, urine, and stool cultures were negative. Results of stool studies for Clostridium dificile toxin were negative. Computed tomographic imaging of the abdomen and pelvis was uninformative. A sample of the patients stool was stained with a modified acid-fast stain (Figure).
What is the diagnosis?
