title: Delirium and the dexamethasone suppression test in the elderly.
abstract: It has been suggested that delirium in the elderly is caused by abnormally high levels of circulating glucocorticoids or by an increased vulnerability to their effects. We performed a dexamethasone suppression test (DST) in 16 consecutive patients without depression or dementia admitted to an acute-care geriatric unit with a clinical diagnosis of lower respiratory tract infection. Seven of 9 (78%) patients who developed delirium were non-suppressors on the DST compared with 1 of 7 (14%) patients without delirium (p = 0.04). Clinical and laboratory indicators of the severity of illness did not differ between the two groups. Of the 8 patients with an abnormal DST, 1 died and another was not available for repeat assessment. On re-examination 8 weeks later, after resolution of the delirium and of the chest infection, 5 of 6 non-suppressors still had an abnormal DST. It is known that some non-demented and non-depressed elderly patients fail to suppress cortisol in response to 1 mg of dexamethasone. Our results suggest that such patients may be at increased risk for developing delirium during acute illness.
authors.affiliation: Department of Geriatric Medicine, Beaumont Hospital, Dublin, Ireland.
authors.forename: S T
authors.initials: ST
authors.lastname: O'Keeffe
authors.forename: J G
authors.initials: JG
authors.lastname: Devlin
mesh_terms: D000208:Acute Disease; D000368:Aged; D003693:Delirium / Q000097:blood* / Q000175:diagnosis* / Q000209:etiology; D003907:Dexamethasone; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D008297:Male; D011569:Psychiatric Status Rating Scales; D012141:Respiratory Tract Infections / Q000523:psychology; D013315:Stress, Psychological / Q000523:psychology
chemical_list: D003907:Dexamethasone; D006854:Hydrocortisone