Diarrhea History Assessment

  • Duration: If <14 days, likely infectious etiology or Clostridium difficile (C. diff).

  • Bowel Movement Frequency: Quantify daily stool count.

  • Associated Symptoms:

    • Presence of blood, pus, nocturnal diarrhea, fevers, joint pain, oral ulcers, or eye redness (consider inflammatory bowel disease - IBD).

    • Symptoms suggestive of dehydration (e.g., orthostatic hypotension).

  • Red Flags:

    • Onset age >50, rectal bleeding, melena, progressive abdominal pain, unexplained weight loss/fever, nocturnal diarrhea, iron deficiency anemia, elevated ESR/CRP, elevated fecal calprotectin, family history of colorectal cancer, IBD, or celiac disease.

  • Dietary Triggers: Consider lactose intolerance, food-related patterns, sorbitol ingestion, or excessive alcohol intake.

  • Relevant Medical History:

    • Colonoscopy history

    • Pancreatic disorders

    • Bowel resections: Ileal resection, Crohn’s disease, post-cholecystectomy, vagotomy, radiation enteritis, celiac disease, or chronic pancreatitis (concern for bile acid diarrhea).

  • Medications/Supplements:

    • Olmesartan, olestra, magnesium, ACE inhibitors, NSAIDs, DPP-4 inhibitors (-gliptins), antibiotics, antiarrhythmics, chemotherapy.

  • Systemic Diseases:

    • History of lymphoma, chronic pancreatitis, diabetes (concern for autonomic neuropathy), systemic sclerosis.

  • Sexual History: Consider sexually transmitted proctitis (gonorrhea, chlamydia, herpes simplex virus etc).

  • Other Considerations:

    • Small intestinal bacterial overgrowth (SIBO) risk factors: Diabetes, scleroderma, pseudo-obstruction, ileal resection, diverticulosis, strictures, long-term PPI use.

    • Recent cholecystectomy: Occurs in ~10% of cases.

Initial Workup for Diarrhea

  • Laboratory Tests:

    • Electrolytes, fecal WBC, stool cultures.

    • Fecal calprotectin, CRP, ESR.

    • TSH, CBC, CMP.

    • Iron panel (Ferritin, Iron, % Sat, TIBC, Reticulocyte count) – consider small bowel enteropathy/celiac disease.

    • Celiac panel.

    • Vitamin deficiencies: Vitamin B12, 25-OH Vitamin D.

    • HIV-related causes: CMV, Cryptosporidium, Mycobacterium avium complex (MAC), Histoplasma, Cryptococcus.

    • Microbiological Workup:

      • Stool studies: Ova & parasites, bacterial cultures, C. diff, microsporidia, norovirus, adenovirus, rotavirus.

      • If immunocompromised, add multi-drug resistant (MDR) stool studies.

    • Dietary considerations:

      • Increase fiber intake to 30g/day.

    • Symptom Management:

      • If afebrile, no bloody stools, and infectious diarrhea has been ruled out consider Loperamide 4mg (max 16mg/day, ideally 30 min before meals).

      • If diarrhea persists: consider Lomotil, monitor for constipation from high-dose anti-diarrheals.

      • If pancreatic insufficiency suspected: Check fecal elastase (normal >200 mcg/g; mild/moderate 100–200 mcg/g; severe <100 mcg/g).

    • Further Evaluations if Needed:

      • Neuroendocrine tumor workup: VIP, gastrin, chromogranin A, urine 5-HIAA.

      • Celiac disease testing: Anti-Ttg IgA, but If IgA deficient, check IgG endomysial or IgG TTG.

      • Carcinoid syndrome evaluation.

    • Stool and Nutritional Assessments:

      • 72-hour stool weight and fecal fat quantification.

      • Vitamin levels: A, E, 25-OH Vitamin D, Zinc, B12.