Anterior Pituitary Function in the Vegetative State

Abstract

Anterior pituitary function tests were performed in 33 patients in the vegetative state, and the results were assessed for correlation with various clinical factors. Radioimmunoassays were employed to measure the secretion of growth hormone and cortisol during insulin tolerance testing (regular insulin, 0.15 to 0.20 U/kg), luteinizing hormone and follicle stimulating hormone under administration of luteinizing hormone-releasing hormone (100 micrograms), and thyroid stimulating hormone and prolactin under administration of thyroid-releasing hormone (500 micrograms). Impairment rate, defined as number of abnormal hormone secretions divided by number of hormones examined, was calculated for each patient. The data were statistically assessed by analysis of variance in terms of disease, sex, age, site of lesion, etiology of vegetative state, duration of illness, brain atrophy as demonstrated by computed tomography, and Hockaday's electroencephalographic (EEG) grade. The results were as follows. 1) The levels of growth hormone, luteinizing hormone, follicle stimulating hormone, cortisol, thyroid stimulating hormone, and prolactin were abnormal in 70%, 67%, 45%, 39%, 36%, and 15% of cases, respectively. 2) Anterior pituitary hormone secretion was impaired in all 33 patients, severely in 52%. 3) The impairement rate was significantly increased in patients with ruptured cerebral aneurysms, primary coma, severe brain atrophy, and abnormal EEGs. 4) The impairment rate tended to be higher in long-term vegetative patients. These results suggest that, in the vegetative state, impairment of anterior pituitary function frequently occurs at the onset of disease and worsens over time.