Diarrhea is a familiar phenomenon defined as unusually frequent or unusually soft or liquid bowel movements. It is the opposite of constipation. The word diarrhea with its odd spelling is a near steal from the Greek diarrhoia meaning "a flowing through."
Diarrhea can be acute, that is, sudden in onset and short-lived, or it may be prolonged. Most acute episodes of diarrhea are due to viral infections and last three to five days. Prolonged diarrhea -- lasting more than four to six weeks -- usually is due to an underlying gastrointestinal disease, the most common of which are diseases that cause inflammation and malabsorption of food. Intermittent diarrhea, sometimes alternating with constipation, is part of a syndrome of functional bowel disease called irritable bowel syndrome (IBS). In most cases, treatment of diarrhea includes drinking plenty of fluids to prevent dehydration and over-the-counter remedies to decrease and solidify bowel movements. Evaluation by a physician generally is needed if diarrhea is severe, results in dehydration, persists for more than a couple of weeks (chronic diarrhea), or if there is a high fever or blood in the stools.
Other causes of persisting diarrhea include food-handler's diarrhea (Campylobacter infection and others), parasite infection (amebiosis, etc.), cholera, cryptosporidiosis, food poisoning, giardiasis, Norwalk virus, rotavirus, salmonellosis, shigellosis, traveler's diarrhea, and inflammatory bowel disease (Crohn's disease and ulcerative colitis), and medication toxicity.
Diarrhea and loose stools can be associated with
- pus or blood in the stool,
- watery stool,
- abdominal bloating,
- abdominal cramps,
- urgency of bowel movements, and
- belly pain.
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.
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