Dehydration in the elderly: insidious and manageable.

Dehydration in the elderly results from inadequate water replacement, and associated mortality may be high when dehydration is severe. The elderly are at an elevated risk for dehydration, due to decreased thirst perception, decreased water intake, abnormal vasopressin responses to osmotic stimuli, and a predisposition to mild nephrogenic diabetes insipidus. In addition, elderly patients with chronic physical and/or mental disabilities are often unable to drink or obtain water themselves. For these high-risk patients, the physician's role is to initiate measures to prevent dehydration, including fluid orders and intake documentation.