Diarrhea

Chronic Watery Diarrhea

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Chronic Watery Diarrhea, Secretory Diarrhea, Osmotic Diarrhea, Functional Chronic Diarrhea, Functional Diarrhea, Functional Chronic Watery Diarrhea, Non-Celiac Gluten Sensitivity, Paradoxical Diarrhea ( C2363945)

  • Definitions
  1. Chronic Watery Diarrhea
    1. Loose stools lasting >4 weeks AND
    2. No features of Chronic Fatty Diarrhea (>14 grams fecal fat in 24 hours) AND
    3. No features of Chronic Inflammatory Diarrhea (e.g. Fecal Calprotectin or lactoferrin, fecal immunochemistry test)
  • Types
  1. Secretory Chronic Watery Diarrhea
    1. Decreased bowel water absorption
    2. High stool volumes regardless of day or night and even when Fasting
  2. Osmotic Chronic Watery Diarrhea
    1. Intestinal water retention due to unabsorbed solutes (high stool osmotic gap)
  3. Functional Chronic Watery Diarrhea (Diagnoses of exclusion)
    1. Diarrhea Dominant Irritable Bowel Syndrome
      1. Rome 4 Criteria: Diarrhea WITH Defecation related Abdominal Pain weekly for last 3 months, onset >6 months
    2. Functional Diarrhea
      1. Distinct diagnosis from Irritable Bowel Syndrome
      2. Small volume (<350 ml/day) watery stools, better at night and with Fasting
      3. Rome 4 Criteria: Diarrhea >25% of stools for 3 months WITHOUT Abdominal Pain or bloating
    3. Non-Celiac Gluten Sensitivity
      1. Gluten Enteropathy-like presentation with negative lab markers and diagnostics
    4. Paradoxical Diarrhea
      1. Stool impaction (on rectal exam) with leakage of liquid stool around firm stool
      2. History of Constipation, Chronic Opioid use or Hemorrhoids
  • Causes
  • Osmotic Diarrhea
  1. Findings
    1. Fecal osmotic gap >125 mOsm/kg
  2. Carbohydrate Malabsorption
    1. Lactose malabsorption (Lactose Intolerance)
    2. Fructose malabsorption
    3. Glucose malabsorption
    4. Galactose malabsorption
    5. Gluten-sensitive Enteropathy (Celiac Sprue)
      1. May also cause Chronic Fatty Diarrhea (Diarrhea due to Malabsorption)
  3. Magnesium
    1. Magnesium Sulfate (Laxatives)
    2. Magnesium Antacids
    3. Magnesium Laxatives
  4. Excessive High sugar juice intake
    1. Apple juice
    2. Pear juice
  5. Sugar Alcohols
    1. Mannitol ingestion
    2. Sorbitol ingestion (chewing gum Diarrhea)
    3. Xylitol
  6. Laxatives
    1. Sodium phosphate
    2. Sodium citrate
    3. Lactulose therapy
    4. Sodium Sulfate (Glauber's Salt)
  • Causes
  • Secretory Diarrhea
  1. Findings
    1. Large volume stools (>1 L/day, with Diarrhea persisting at night and with Fasting)
    2. Fecal osmotic gap <50 mOsm/kg
  2. Post-operative changes
    1. Cholecystectomy
    2. Gastrectomy
    3. Vagotomy
    4. Ileocolic resection
  3. Structural changes and lesions
    1. Secretory villous adenoma of Rectum
    2. Small Bowel total villous atrophy
    3. Intestinal Lymphoma
    4. Bile Acid Malabsorption
  4. Inflammatory Bowel Disease
    1. Usually causes Chronic Inflammatory Diarrhea
    2. Crohn's Disease (ileitis)
    3. Ulcerative Colitis
    4. Microscopic Colitis (Lymphocytic Colitis, Collagenous collitis)
  5. Endocrine Causes
    1. Hyperthyroidism
    2. Medullary Thyroid Carcinoma
    3. Islet Cell Tumor
    4. Gastrinoma (Zollinger-Ellison Syndrome)
    5. Vipoma (WDHA: Watery Diarrhea, Hypokalemia, achlorhydria) or Pseudopancreatic Cholera Syndrome
    6. Malignant Carcinoid syndrome
    7. Mastocytosis
    8. Pheochromocytoma
  6. Collagen Vascular Disease
    1. Systemic Lupus Erythematosus
    2. Scleroderma
    3. Mixed Connective Tissue Disease
    4. Behcet Syndrome
  7. Drug-Induced Diarrhea
    1. Non-Osmotic Laxatives (e.g. senna, Docusate)
    2. Alcoholism
  8. Infectious Disease
    1. Bacterial Infections
      1. Chronic infections (e.g. granulomatous, enterotoxins) in immunocompromised patients
      2. Diverticulitis
      3. Brainerd Diarrhea
        1. Persistent Diarrhea after raw milk intake
    2. Parasite infections
      1. Cryptosporidiosis
        1. Also causes osmotic Diarrhea due to Malabsorption
      2. Cyclospora (Cyclosporiasis)
      3. Trichuris trichiura (Whipworm)
  • Labs
  1. See Chronic Diarrhea
  2. Fecal electrolytes (fecal Sodium, fecal Potassium)
    1. Electrolytes increased in Secretory Diarrhea
      1. Electrolytes negligible in Osmotic Diarrhea
    2. Small osmotic gap <50 mOsm/kg in Secretory Diarrhea
  3. Stool pH
    1. pH <6 in carbohydrate malabsorption
  • Evaluation
  1. Osmotic Diarrhea: Fecal osmotic gap >125 mOsm/kg
    1. If Fasting improves Diarrhea, consider breath hydrogen test for Lactose Intolerance (or empiric avoidance)
  2. Secretory Diarrhea: Fecal osmotic gap <50 mOsm/kg
    1. Obtain stool tests (Ova and Parasites, Giardia, culture and sensitivity, specific infections)
    2. Colonoscopy
    3. Obtain TSH, ACTH
    4. Consider testing for Carcinoid, Gastrinoma, Pheochromocytoma, mastocytosis
    5. Consider autoimmune labs (e.g. ANA)
  3. Functional Diarrhea: Fecal osmotic gap normal
    1. Trial on empiric Irritable Bowel Syndrome management (dietary modification)
    2. If no improvement, test for Celiac Sprue
  • References
  1. Schiller in Feldman (2002) Sleisenger GI, p. 136
  2. Burgers (2020) Am Fam Physician 101(8): 472-80 [PubMed]