Chronic Diarrhea

Aka: Chronic Diarrhea

1. See Also
   1. Acute Diarrhea
   2. Diarrhea in Cancer
   3. Diarrhea in Children
   4. Diarrhea in Pregnancy
   5. Diarrhea in HIV
2. Definition
   1. Persistent Diarrhea >4 weeks
3. Causes
   1. Chronic Fatty Diarrhea
      1. Diarrhea due to Malabsorption
   2. Chronic Inflammatory Diarrhea
      1. Infectious Diarrhea
   3. Chronic Watery Diarrhea
      1. Secretory Diarrhea
         1. Large volume stools >1 L/day and not better over night or with Fasting
      2. Osmotic Diarrhea
      3. Drug-Induced Diarrhea
      4. Functional Chronic Diarrhea (diagnosis of exclusion)
         1. Small volume stools (<350 ml/day and better over night and with Fasting)
         2. Irritable Bowel Syndrome
4. History
   1. Age
      1. Young patients
         1. Inflammatory Bowel Disease
         2. Tuberculosis
         3. Functional bowel disorder (Irritable Bowel Syndrome)
      2. Older patients
         1. Colon Cancer
         2. Diverticulitis
   2. Diarrhea pattern
      1. Diarrhea alternates with Constipation
         1. Colon Cancer
         2. Laxative abuse
         3. Diverticulitis
         4. Functional bowel disorder (Irritable Bowel Syndrome)
      2. Intermittent Diarrhea
         1. Diverticulitis
         2. Functional bowel disorder (Irritable Bowel Syndrome)
         3. Malabsorption
      3. Persistent Diarrhea
         1. Inflammatory Bowel Disease
         2. Laxative abuse
   3. Differentiating Small Bowel from Large Bowel
      1. Small Intestine or proximal colon involved
         1. Large stool Diarrhea
         2. Abdominal cramping persists after Defecation
      2. Distal colon involved
         1. Small stool Diarrhea
         2. Abdominal cramping relieved by Defecation
   4. Diurnal variation
      1. No relationship to time of day: Infectious Diarrhea
      2. Morning Diarrhea and after meals
         1. Gastric cause
         2. Functional bowel disorder (e.g. Irritable Bowel Syndrome)
         3. Inflammatory Bowel Disease
      3. Nocturnal Diarrhea (always organic)
         1. Diabetic Neuropathy
         2. Inflammatory Bowel Disease
   5. Weight Loss
      1. Despite normal appetite
         1. Hyperthyroidism
         2. Malabsorption (e.g. Celiac Sprue)
         3. Giardia
         4. Cryptosporidium
         5. Cyclospora
      2. Associated with fever
         1. Inflammatory Bowel Disease
      3. Weight loss prior to Diarrhea onset
         1. Pancreatic Cancer
         2. Tuberculosis
         3. Diabetes Mellitus
         4. Hyperthyroidism
         5. Malabsorption
   6. Stool characteristics
      1. Water: Chronic Watery Diarrhea
      2. Blood, pus or mucus: Chronic Inflammatory Diarrhea
      3. Foul, bulky, greasy stools: Chronic Fatty Diarrhea
   7. Medication and dietary intakes
      1. See Drug-Induced Diarrhea
      2. See Foodborne Illness
      3. See Waterborne Illness
      4. High fructose corn syrup
      5. Excessive Sorbitol, mannitol (chewing gum)
      6. Artificial Sweeteners (e.g. Sucralose, chewing gum, fruit juice, soft drinks)
      7. Excessive coffee or other Caffeine
   8. Recent travel to undeveloped areas
      1. See Traveler's Diarrhea
      2. See Infectious Diarrhea
5. Red Flags: Suggestive of organic cause
   1. Painless Diarrhea
   2. Recent onset in an older patient
   3. Nocturnal Diarrhea (especially if wakes patient)
   4. Weight loss
   5. Blood in stool
   6. Large stool volumes: >400 grams stool per day
   7. Anemia
   8. Hypoalbuminemia
   9. Erythrocyte Sedimentation Rate increased
6. Signs
   1. Vital Signs
      1. Weight loss (red flag - see causes above)
   2. Eye Exam
      1. Episcleritis (Inflammatory Bowel Disease)
   3. Neck exam
      1. Lymphadenopathy
      2. Thyromegaly (Hyperthyroidism)
   4. Abdominal exam
      1. Surgical scars
      2. Hypermotility
      3. Hepatomegaly
      4. Abdominal Tenderness
      5. Abdominal mass
   5. Rectal exam
      1. Anal fistula (Crohn Disease)
      2. Rectal exam (Stool impaction - pseudo-Diarrhea)
      3. Fecal Occult Blood Testing
   6. Skin exam
      1. Dermatitis Herpetiformis (Celiac Sprue)
7. Labs
   1. Blood tests
      1. Complete Blood Count
      2. Thyroid Stimulating Hormone (TSH)
      3. Serum electrolytes
      4. Liver Function Tests
      5. Serum Albumin
      6. Erythrocyte Sedimentation Rate
      7. Iron Deficiency Anemia (Celiac Sprue)
   2. Stool evaluation
      1. Stool pH
         1. pH <5.5 in carbohydrate malabsorption (e.g. Lactose Intolerance)
      2. Fecal electrolytes (Fecal Sodium and Osmolar Gap)
         1. Differentiates Chronic Watery Diarrhea category (secretory from osmotic)
      3. Fecal Occult Blood Test
      4. Fecal Leukocytes
      5. Fecal fat (abnormal if >14 grams/24 hours)
      6. Stool Ova and Parasite (2-3 samples)
      7. Giardia lamblia antigen
         1. Indicated for Diarrhea >7 days and >10 stools/day
      8. Clostridium difficile Toxin
         1. Indicated if recent antibiotics or hospitalization
      9. Cryptosporidium stool antigen test
         1. Indicated in immune compromised state
      10. Consider testing stools for Laxative abuse
          1. Stool Laxative screen (Sodium, Potassium, Magnesium, phosphate, sulfate, Phenolphthalein, Bisacodyl)
8. Diagnostics
   1. Colonoscopy with biopsy
      1. May be required in persistent or refractory cases, red flags (see above) or to make formal diagnosis (e.g. Microscopic Colitis)
9. Management
   1. Direct to specific causes based on stool
   2. Chronic Fatty Diarrhea (Diarrhea due to Malabsorption)
   3. Chronic Inflammatory Diarrhea
   4. Chronic Watery Diarrhea
10. References
    1. Frank in Friedman (1991) Medical Diagnosis, p. 186-9
    2. Schiller in Feldman (2002) Sleisenger GI, p. 136
    3. Juckett (2011) Am Fam Physician 84(10): 1119-26 [PubMed]
    4. Schiller (2004) Gastroenterology 127(1): 287-93 [PubMed]