Hypothalamic hypothyroidism and hypogonadism in prolonged traumatic coma

Abstract

Prolonged coma after head trauma is associated with depletion of cyclic (c)AMP in the CSF. Because cAMP was previously implicated in neuroendocrine secretion, the pituitary-hypothalamic function was examined in 15 adult male patients (to exclude the effects of puberty and menses) with traumatic coma lasting longer than 2 wk. Ventricular CSF cAMP was measured at 2-4 day intervals for 10-25 days. Simultaneously, plasma hormone concentrations were also determined. In all 15 cases, CSF cAMP and plasma levels of thyroid-stimulating horomone (TSH), thyroxine (T4), free T4, triiodothyronine (T3), luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone became subnormal. In 11 patients whose level of consciousness fluctuated, the reduction in plasma T4 and testosterone were proportional to both severity of coma (r [correlation coefficient] > 0.81, P < 0.05) and depletion of CSF cAMP (r > 0.81, P < 0.05). In 4 patients who remained deeply comatose for 17-25 days, the hypothyroidism and hypogonadism persisted. In 6 patients who regained consciousness, both endocrine defects improved partially or completely. Injection of thyrotropic-releasing hormone and gonadotropic-releasing hormone elicited normal or supernormal increases in plasma concentrations of TSH, LH and FSH, suggesting a suprahypophyseal deficiency. Suprahypophyseal hypothyroidism and hypogonadism may occur regularly in patients with traumatic coma lasting longer than 2 wk.