Panhypopituitarism secondary to head trauma: evidence for a hypothalamic origin of the deficit

A complete endocrinological exploration was performed in a 23 year old male patient who presented clinical signs of an acquired panhypopituitarism which appeared two months after a severe head trauma, in order to determine whether the deficit lay in the hypothalamus or in the pituitary. TSH had normal basal levels, but presented a delayed rise after TRH administration. PRL rose normally after TRH administration, but presented a blunted response to both metoclopramide and insulin tolerance test. Cortisol rose significatively after lysine vasopresssin, but failed to rise during insulin hypoglycaemia. These results are consistent with a hypothalamic defect. Extensive endocrinological data are often lacking in the few similar cases reported in the literature. Prl and TSH were usually found to have normal basal levels while other pituitary hormones were profoundly lowered. This was interpretated as a pituitary defect with some intact areas of the anterior lobe. However, this may also suggest a hypothalamic defect which could have been assessed by more discriminative tests.