Cortisol deficient state. A cause of reversible cognitive impairment and delirium in the elderly.

An elderly female who had suffered a stroke was admitted to the Jewish Institute for Geriatric Care (JIGC) for rehabilitation. Three years previously she was found to have a pituitary macroadenoma (prolactinoma) that was treated with radiation therapy. She had been on thyroid replacement for secondary hypothyroidism. Upon admission she was found to have severe cognitive impairment in association with a low plasma cortisol level. After treatment with prednisone there was a dramatic improvement in cognitive function and the patient was able to participate in a rehabilitation program.