dehydration

dehydration Excessive loss of body water. Diseases of the gastrointestinal tract that cause vomiting or diarrhea may lead to dehydration. There are a number of other causes of dehydration, including overheating (hyperthermia), prolonged vigorous exercise (as in a marathon), kidney disease, and medications (diuretics). One clue to dehydration is a rapid drop in weight. Symptoms include increasing thirst, dry mouth, weakness or lightheadedness (particularly when it worsens on standing), and a darkening of or decrease in urination. Severe dehydration can lead to changes in the body’s chemistry, kidney failure, and death. Intravenous or oral fluid replacement may be needed in some cases. See also diarrhea; hyperthermia.