Diarrhea: pathogenesis and diagnostic techniques.

Daily fecal weight is the feature most useful in defining diarrhea, as normal weights for various societies are known. Diarrhea is associated with increased fecal water excretion, with heightened sensitivity of the rectal mucosa, and with exudation of mucus. It occurs acutely, as in gastroenteritis, bacterial dysenteries, and parasitic infections, and chronically, as in functional disorders, malabsorption syndromes, and inflammatory bowel disease. Many seemingly unrelated diseases can also cause diarrhea. The patient's history as well as macroscopic, microscopic, and chemical analysis of stools will offer major clues to the cause of the ciarrhea.