Major Causes of Chronic Diarrhea According to Predominant Pathophysiologic Mechanism | |||
| Secretory Causes | |||
| Exogenous stimulant laxatives | |||
| Chronic ethanol ingestion | |||
| Other drugs and toxins | |||
| Endogenous laxatives (dihydroxy bile acids) | |||
| Idiopathic secretory diarrhea or bile acid diarrhea | |||
| Certain bacterial infections | |||
| Bowel resection, disease, or fistula (↓ absorption) | |||
| Partial bowel obstruction or fecal impaction | |||
| Hormone-producing tumors (carcinoid, VIPoma, medullary cancer of thyroid, mastocytosis, gastrinoma, colorectal villous adenoma) | |||
| Addison's disease | |||
| Congenital electrolyte absorption defects | |||
| Osmotic Causes | |||
| Osmotic laxatives (Mg2+ , PO4-3 , SO4-2 ) | |||
| Lactase and other disaccharide deficiencies | |||
| Nonabsorbable carbohydrates (sorbitol, lactulose, polyethylene glycol) | |||
| Gluten and FODMAP intolerance | |||
| Steatorrheal Causes | |||
| Intraluminal maldigestion (pancreatic exocrine insufficiency, bacterial overgrowth, bariatric surgery, liver disease) | |||
| Mucosal malabsorption (celiac sprue, Whipple's disease, infections, abetalipoproteinemia, ischemia, drug-induced enteropathy) | |||
| Postmucosal obstruction (1° or 2° lymphatic obstruction) | |||
| Inflammatory Causes | |||
| Idiopathic inflammatory bowel disease (Crohn's, chronic ulcerative colitis) | |||
| Lymphocytic and collagenous colitis | |||
| Immune-related mucosal disease (1° or 2° immunodeficiencies, food allergy, eosinophilic gastroenteritis, graft-versus-host disease) | |||
| Infections (invasive bacteria, viruses, and parasites, Brainerd diarrhea) | |||
| Radiation injury | |||
| Gastrointestinal malignancies | |||
| Dysmotile Causes | |||
| Irritable bowel syndrome (including postinfectious IBS) | |||
| Visceral neuromyopathies | |||
| Hyperthyroidism | |||
| Drugs (prokinetic agents) | |||
| Postvagotomy | |||
| Factitial Causes | |||
| Munchausen | |||
| Eating disorders | |||
| Iatrogenic Causes | |||
| Cholecystectomy | |||
| Ileal resection | |||
| Bariatric surgery | |||
| Vagotomy, fundoplication |