Diarrhea and malabsorption in the elderly.

Physicians who care for elderly patients should be alert to the possible presence of diarrhea and malabsorption. Older patients may not admit to having chronic diarrhea, particularly if they also are incontinent. If diarrhea is of short duration, an infectious cause is at least as common as in the young. Institutionalized elderly are particularly prone to gastrointestinal infections, but the manifestations may not be overt. When an intestinal infection and potential medication-induced gastrointestinal disturbances have been excluded, the differential diagnosis of diarrhea in the elderly is the same as in the young. Causes include intestinal malabsorption, even though diarrhea is a less common manifestation of malabsorption in the old than in younger patients. In the elderly, micronutrient deficiency is a common presenting clinical picture; because the symptoms of malabsorption are covert, the diagnosis often is delayed, and nutritional deficiencies are more common and more severe than in the young. Because the elderly have less nutritional reserve than the young, these deficiencies are clinically much more devastating in the elderly. Although the causes of malabsorption, as a whole, are similar in older and younger patients, chronic pancreatic insufficiency of unknown cause and intestinal bacterial overgrowth without an anatomic abnormality of the small intestine are syndromes that are specific to the elderly and must be considered in any older patient with unexplained weight loss or failure to thrive. Often, therapeutic trials are necessary to establish a potential diagnosis.