Pituitary insufficiency following head injury.

A 32-year-old man developed panhypopituitarism and diabetes insipidus shortly after sustaining a head injury. Hormonal investigation showed that basal prolactin levels were moderately elevated the first two years after the accident, but later returned to normal. There was no rise in prolactin after administration on chlorpromazine, and the response to thyrotropin-releasing hormone was attenuated. Basal luteinizing hormone and follicle-stimulating hormone levels were low and there was no change after administration of luteinizing-hormone-releasing hormone. There was also no growth hormone elevation following arginine infusion. On the other hand, there was a normal but delayed elevation of thyrotropin in response to thyrotropin-releasing hormone. Appropriate stimulation tests showed normal responsiveness of the thyroid, adrenals and testes. These findings are compatible with an injury to the pituitary stalk, damaging the neurohypophyseal tract and affecting the blood supply to the pituitary gland.