Dehydration occurs when the body doesn't have enough water and other fluids to carry out its normal functions. Common causes of dehydration include intense bouts of diarrhea, vomiting, fever or excessive sweating. Inadequate intake of water during hot weather or exercise may also deplete the body's water supply.

Dehydration is a serious acute condition that occurs in frail patients and patients with other underlying illnesses following insufficient attention and support for fluid intake. Dehydration can treated in an outpatient setting, but the elderly, very young children, frail patients or patients with serious medical conditions may need extra care to prevent fatal complications. Dehydration is not a measure of hospital quality, but rather one way to measure outpatient care for dehydration. Proper outpatient treatment for dehydration may reduce the likelihood of hospital admission for dehydration, especially for patients with chronic medical conditions.