Delirium episodes during the course of clinically diagnosed Alzheimer's disease.

A retrospective review was conducted of 122 charts of patients with clinically diagnosed Alzheimer's disease (CDAD) who had participated in a longitudinal dementia study at the Mayo Clinic from 1965 to 1970. DSM-III-R diagnoses were assigned based on the longitudinal description of symptoms detailed in the Mayo Clinic medical records of the hospitalizations; clinic, home, and nursing home visits; and state hospital admissions. Thirty patients (25%) were found to have a delirium episode during their course of CDAD that occurred during inpatient admissions; 50% (15 of 30) of the delirium episode occurred in patients ages 80 to 89. Among patients with a delirium episode, 50% died within one year of the delirium episode and 64% died within two years. Of 13 patients, 10 (77%) had multiple delirium episodes within two years. Admitting diagnoses were mainly primary degenerative dementia of the Alzheimer's type (PDDAT) or PDDAT with delirium. Only 3 (10%) demented patients experienced delirium episodes during a medical admission. No deaths occurred during hospitalization for the years covered by this study. A psychiatric consultation was requested in only 17 (14%) patients; 88% of these patients received diagnoses involving PDDAT, late onset. An additional diagnosis included depressive disorders. Psychopharmacology was the major management strategy (82% of patients with a delirium episode received medication) with a resolution of symptoms within 48 hours. At discharge, only 2 (7%) patients failed to clear the increased degree of confusion.