A 45-year-old man comes to the physician because of a 3-week history of diarrhea and a 2.2-kg (5-lb) weight loss. He reports a several weeks of progressive fever, night sweats, and generalized weakness. . He has HIV, gastroesophageal reflux disease, and hypertension. Current medications include chlorthalidone, omeprazole, emtricitabine, tenofovir, and efavirenz. He reports taking efavirenz irregularly. He is employed as a sales manager and regularly flies to South America. Physical examination shows mucosal pallor, generalized lymphadenopathy, and hepatosplenomegaly. CD4+ T-lymphocyte count is 20/mm3. Nucleic acid amplification test of the sample for Mycobacterium tuberculosis is negative. Which of the following pathogens is the most likely cause of this patient's illness?

Question

A 45-year-old man comes to the physician because of a 3-week history of diarrhea and a 2.2-kg (5-lb) weight loss. He reports a several weeks of progressive fever, night sweats, and generalized weakness. . He has HIV, gastroesophageal reflux disease, and hypertension. Current medications include chlorthalidone, omeprazole, emtricitabine, tenofovir, and efavirenz. He reports taking efavirenz irregularly. He is employed as a sales manager and regularly flies to South America. Physical examination shows mucosal pallor, generalized lymphadenopathy, and hepatosplenomegaly. CD4+ T-lymphocyte count is 20/mm3. Nucleic acid amplification test of the sample for Mycobacterium tuberculosis is negative.  Which of the following pathogens is the most likely cause of this patient's illness?

Quizplus · Accepted Answer

Eductional Objective: Mycobacterium avium complex (MAC) infections are common in patients with advanced AIDS.  The bacterium often spreads through the bloodstream and reticuloendothelial system and causes nonspecific symptoms (eg, fever, fatigue, weight loss, diarrhea), lymphadenopathy, and hepatosplenomegaly.  Diagnosis is often made on blood culture or bone marrow aspirate (intracellular acid-fast bacteria that are not Mycobacterium tuberculosis).

A 45-Year-Old Man Comes to the Physician Because of a 3-Week