What causes of chronic diarrhea may be difficult to diagnose?
• Fecal incontinence
• Iatrogenic diarrhea (drugs, surgery, radiation)
• Surreptitious laxative ingestion
• Microscopic colitis syndrome
• Bile acid–induced diarrhea
• Small bowel bacterial overgrowth
• Pancreatic exocrine insufficiency
• Carbohydrate malabsorption
• Peptide-secreting tumors
• Chronic idiopathic secretory diarrhea
These conditions are seen in referral centers after routine evaluation has failed to disclose a diagnosis. In general, the tests necessary to make these diagnoses are not difficult, but have not been done because physicians have not considered these diagnoses in the differential diagnosis of chronic diarrhea.