Infectious causes of diarrhea (“gay bowel syndrome”, see 10.61) may include:
(1) pathogenic enteric bacteria (Shigella, Salmonella, etc)
(2) Clostridium difficile
(3) viral infection (CMV, enterovirus, etc)
(4) parasites (Entamoeba histolytica, Cryptosporidium, Microsporidium, other)
Additional causes of diarrhea may include:
(5) B-cell lymphoma
(6) Kaposi-sarcoma
(7) lactose, fructose or other food intolerance (often with osmotic load)
(8) food allergy
(9) medications, including HAART
(10) drugs of abuse
(11) irritable bowel syndrome
(12) inflammatory bowel disease
(13) idiopathic (diarrhea without identifiable cause despite a complete evaluation)