Mycobacterium avium complex enteritis; cytomegalovirus; Whipple disease; sprue: what endoscopic findings reveal the cause of worsening diarrhea in this HIV-infected man with a CD4 cell count of 32/μL?
A 54-year-old man with HIV infection presents with increasingly worsening diarrhea. His CD4 cell count is 32/µL. Upper endoscopy with duodenal biopsies is performed. Specimens reveal sheets of foamy macrophages in the lamina propria. Periodic acid–Schiff (PAS) and acid-fast bacillus stains are notable for rod-shaped organisms.
What is the most likely diagnosis?
a. Mycobacterium avium complex
c. Whipple disease
d. Tropical sprue
Mycobacterium avium complex (MAC) enteritis can affect patients with HIV infection-particularly those with a low CD4 cell count (< 50/µL). Both MAC and Whipple disease may reveal foamy macrophages on biopsies and both are PAS-positive; however, only MAC would also demonstrate acid-fast macrophage inclusions.