Classification of Diarrhea

Temporal

Acute (< 6 weeks) versus chronic (>6 weeks duration).

Type

  1. Inflammatory (blood and mucous)
  2. Watery
    1. Secretory (not better when fasting). Typically a normal osmolal gap.
    2. Osmotic (better when fasting)
  3. Malassimilation (steatorrhea)
    1. Maldigestion
    2. Malabsorption
  4. Motility

Etiologies

Classification Causes
Inflammatory Inflammatory bowel disease, ischemic colitis, infectious colitis
Watery-Osmotic Mannitol and artificial sugars, lactose, osmotic laxatives
Watery-Secretory GI malignancy, cholera/toxins, NE tumours (pheo, VIP, carcinoid), microscopic colitis, thyroid disorders
Malassimilation (Steatorrhea) Celiac disease, small intestinal mucosal disease, Whipple disease, intestinal lymphoma, TB, pancreatic exocrine dysfunction (cystic fibrosis), bile salt deficiency (SIBO), significant ileal disease, post-cholecystectomy
Motility IBS, thyrotoxicosis, dumping syndrome, promotility agent overuse

Inflammatory Diarrhea

Risk Factors to Ask About

  1. Family history
  2. Autoimmune disorders
  3. Smoking
  4. Dietary habits and food/environmental exposures
  5. Immune status
  6. Ethnogeographic origin
  7. Age (young > old, slightly bimodal)

Extraintestinal Manifestations of IBD

  1. Eye inflammation (uveitis, iritis, scleritis...): painful eyes, slit lamp examination needed.
  2. Mucous membrane ulcers: cheek/mouthroof ulcers
  3. Skin manifestations: pyoderma gangrenosum, erythema nodosum
  4. Fistulizing disease: perianal fistulas, abscesses, skin tags. Enterocutaneous. Colovesicular. Enteroenteral.
  5. Spondyloarthritis: nail pitting, dactylitis, enthesitis
  6. Nail clubbing
  7. Kidney stones (hyperoxaluria) --> calcium oxalate stones
  8. Venous thrombosis

Investigations to Consider