Assessment of pituitary function after traumatic brain injury: hypopituitarism is a common problem

Hypopituitarism may occur after traumatic brain injury (TBI). Often, however, these disturbances remain unrecognized, due to unspecific symptomatology and masking by TBI sequalae. However, adequate diagnosis and treatment of hypopituitarism is important, first, to prevent life threatening hormonal crisis, and, second, because hormone replacement might have beneficial effects on rehabilitation after TBI. We have studied pituitary function in 65 patients three months after TBI. In all patients a GHRH + arginine test, a 30-minute ACTH test and basal assessments of thyroid hormones, gonadotrophins, sex steroids, prolactin, and IGF-1 were performed. Impairment of at least one axis of the pituitary have been found in more than half of the patients. In most patients with hypopituitarism only one axis was impaired. The somatotrophic, gonadotrophic, corticoptrophic and thyreotrophic axes were affected to a similar degree. Peak GH levels in the GHRH + arginine test did not correlate with IGF-1 levels but correlated negatively with BMI. Hyperprolactinemia often occured in combination with drugs that may elevate prolactin levels. These results show that hypopituitarism is a common finding after TBI. Mostly only one axis is concerned. These findings strongly suggest that assessment of pituitary function should be performed on a regular basis after TBI. Further studies to evaluate natural course and effects of hormone substitution in posttraumatic hypopituitarism are needed.