Investigation of Anterior Pituitary Function in Elderly In-patients Over the Age of 75

Dynamic pituitary function tests were carried out on 50 randomly selected in-patients, (30 women and 20 men) over the age of 75 during early convalescence. Twenty-five subjects also had CT seans of the pituitary fossa. One male patient had hypogonadotrophic hypogonadism; another had a large prolactinoma and hypothyroidism; these were excluded from the analysis. Of the remaining 48 subjects, 14(29 per cent) had reduced TSH responses to TRH and 28(64 per cent) decreased GH responses to L-dopa compared with our laboratory's reference ranges. Fifteen women (51 per cent) had low basal gonadotrophin levels of which 10(34 per cent) gave a poor LH response to LHRH and eight (27 per cent) a poor FSH response. Forty-three subjects (93 per cent) gave a good ACTH response to metyrapone. Only six subjects (24 per cent) had an apparently normal pituitary fossa; 16(64 per cent) had partially or completely empty fossas. There was no significant correlation between the diminished pituitary responses. Only one patient had responses which suggested panhypopituitarism. There was also no significant correlation between the appearance on CT scan of the pituitary fossa and the results of the dynamic tests. It is suggested that laboratory reference ranges for pituitary function which have been derived from young ambulatory subjects are not appropriate for hospital in-patients over the age of 75. A series of reference ranges for such subjects is proposed.