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Diarrhea

Increased frequency and fluidity of stool.

Causes of Diarrhea

Increases of motility:

  • Stimulation of vagus nerve (PSNS).
  • Gastroenteric reflex (and subsequent secretion of gastrin).
  • Irritation of mucosa (from infection, altered microbes).
  • Physical activity (ambulate your patients!)
  • Reduction in small-intestine time travel time (gastrectomy).
  • Excessive fluid intake.

Increase of poorly absorbable, osmotically active material:

  • Active solutes (carbohydrates, magnesium sulfate) causing H\(_2\)O influx into bowels.
  • Lactose intolerance.
  • Artificial sweeteners.

Secretory:

  • Bacterial toxin (ex: Cholera) induces inflammation.
    • Increases secretion of Cl\(^-\) and H\(_2\)O into intestine.
    • Inhibits resorption.

Exudative:

  • Gut inflammation and exudation of mucous, blood, and protein.
    • Increases osmotic load.
    • Ex: Crohn's disease, ulcerative colitis, CDAD/Cdiff.

Timing of Diarrhea

Acute:

  • Infection.
  • Emotional stress.
  • Osmotically active substances.

Chronic (> 4 weeks):

  • Chronic infection.
  • Malabsorption from IBD or other bowel disorders.

Episodic (note the consistency, frequency, and volume of feces):

  • Ingestion of caffiene.
  • Allergy or intolerence.
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