Diarrhea

Diarrhea is the condition of abnormally frequent or watery bowel movement.

Symptoms

Causes

Nutrient malabsorption is a common cause of diarrhea. Lactose intolerance, which affects half of the world's population, is an example of a carbohydrate-induced diarrhea. The absence or deficiency in the intestinal lactase enzyme leads to poor breakdown of the lactose sugar from dietary sources as milk or cheese. The subsequent buildup of substances (i.e., high lactose concentration, bacterial overgrowth, byproducts of bacterial metabolism) prevent the absorption of water in the intestines.

Lipid malabsorption typically leads to diarrhea and fatty stools (steatorrhea). This can arise from disorders of the bile system, gastric bypass surgery, ileal resection, or intestinal mucosal damage.

Other causes of diarrhea may include inappropriate chloride ion secretion by the intestinal cells, poor salt absorption, abnormal intestinal peristalsis, bacterial overgrowth, or bowel inflammation.

Effects of Diarrhea

Depending on the type of diarrhea, there may be associated underlying symptoms. Particularly with poor lipid absorption, there will be fatty stools and the inability to also absorb calcium, and fat-soluble vitamins (A, D, E, K). These may affect vision, bone, and blood clotting. Oxalate, which is normally excreted with calcium, will instead be absorbed and may lead to kidney stones.

If the diarrhea is a result of abnormalities in bile acid circulation, cholesterol gallstones and jaundice are other possible consequences. Since diarrhea can be caused by a number of factors, the symptoms that present will vary.