Chronic Diarrhea

CAUSES OF CHRONIC DIARRHEA

Suspect / Diagnose in 1° Care Irritable Bowel Syndrome (IBS) Inflammatory Bowel Disease (IBD) Celiac Disease Parasites Malabsorption Syndromes Post-Cholecystectomy Diarrhea Lactose Intolerance Colon Cancer Medications, Laxative Abuse HIV Hyperthyroidism

Let G-I Figure Out Non-Parasitic Infections Chronic Pancreatitis Diverticulitis Diabetic Autonomic Neuropathy Microscopic Colitis Mastocytosis Addison’s Carcinoid & other G-I neuroendocrine tumors

KEY CLUES / RED FLAGS

Finding Weight Loss Bloody Diarrhea Age >50 (at onset) Greasy, Malodorous Stools Hx of 3rd World Travel Men having Sex w/ Men Family Hx IBD Imunocompromised

Consider – Any Organic Etiology – IBD, Colon Cancer, Ameba – Colon Cancer – Malabsorption – Parasites – Parasites; HIV; AIDS infections – IBD – Needs extensive work-up

TESTING

Basic

• CBC — Normocytic Anemia suggests IBD; Microcytic suggests iron deficiency from Cancer, IBD, Celiac Disease
• ESR / CRP — significant elevation suggests IBD, maybe cancer metastases
• Total Protein & Albumin  –  serum globulin >4 g/dL suggests systemic inflammation (how to calculate); low albumin suggests nutritional deficiency)
• Tissue-Transglutaminase Antibody (TTG), IgA fraction (for Celiac Disease)
• Stool for Giardia Antigen
• TSH (hyperthyroidism is unlikely, but a one-time cheap test rules it out)

Other tests

• Ova & Parasites (O&P) [need to order at least 3 separate specimens]
• Stool for C. difficile (if antibiotic use preceded onset of Sx; also in immunocompromised patients)
• Stool C&S (esp. in immunocompromised persons)
• Fecal Fat for malabsorption, esp. if greasy stools.  Ask you lab about single-stool options, before ordering a 72-hour stool collection.  You could let G-I deal with this, since they’d be the ones to work-up positive results anyway.

NEVER an Occult Blood test for Diarrhea (terrible specificity, ? sensitivity).

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