Diarrhea, a condition that has a major impact on global health, is highly correlated with nutritional status. It is an important area of focus due not only to its high worldwide prevalence and health costs, but also because it can be significantly reduced by appropriate interventions and treatment.
Diarrhea has various causes and symptoms, resulting in a wide range of definitions for this illness. The U.S. National Institutes of Health (NIH) defines diarrhea as loose, watery stools occurring more than three times a day, which is the most common definition. The term acutediarrhea is used to describe an episode lasting less than three weeks. Persistent diarrhea is an episode that lasts more than fourteen days, and chronicdiarrhea is the term for recurring episodes of diarrhea. Dysentery is diarrhea that contains blood. The severity of diarrhea ranges from asymptomatic to severe dehydration resulting in death.
Causes of Diarrhea
Diarrhea can present in many ways because it has many potential causes. Most cases of diarrhea are caused by some type of infection. For example, surveillance studies in rural Bangladesh have cited infection as the cause of 86 percent of the cases of diarrhea in that population. This is the case in much of the developing world. Regardless of the cause, diarrhea results from an alteration of the lining of the wall of the intestines. Normal digestion occurs when there is a balance of fluid and nutrients across the bowel wall. Disruption of this process can be caused directly by organisms, toxins, or immune reactions. Any imbalance alters the composition of the stool and the motility (motion) of the bowel wall, resulting in an increased loss of fluid and nutrients. Dehydration is the result of loss of body fluids and electrolytes. A loss of 5 percent of body weight can result in a rapid heart rate, dizziness, decreased urination, disorientation, and even coma. A 10 percent loss of body weight caused by severe diarrhea can lead to acidosis, shock, and death.
People in developing countries suffer most from infectious forms of diarrhea. Most infections pass through a fecal-oral route. This results from environmental causes such as poor sanitation, decreased access to clean water, and a poor understanding of transmission and treatment of disease. These are conditions that arise most frequently in the developing world, though they affect both rural and urban populations. Improvements in these areas result in a dramatic reduction of cases of infectious diarrhea, as shown in studies in numerous developing nations, such as India, Gambia, and elsewhere, where poor socioeconomic status affects a large percentage of the population. Traveler's diarrhea is the result of exposure to such infectious agents when visiting countries where sanitation is inadequate.
Seema Pania Kumar, The Gale Group Inc., Macmillan Reference USA, New York,