Neuroendocrine responses following graded traumatic brain injury in male adults

In an effort to characterize thyroid, gonadal and adrenal function followin g neurotrauma, the present study determined serum concentrations of thyroid -stimulating hormone (TSH), total triiodothyronine (T-3), thyroxine (T-4), testosterone and cortisol over a 7 day period in 31 patients with traumatic brain injury. The study group consisted of eight patients with mild closed head injury (Glasgow Coma Scale-GCS 13-15), 10 patients with extensive pen etrating head injury (GCS 4-6) and 13 patients with blast injuries but with out direct head trauma. The latter group was included in the study because the development of indirect brain trauma has previously been implicated in blast injuries. Patients with multiple injuries were not included. Followin g mild injury (GCS 13-15), TSH was increased up until day 3 after injury. T -3 levels were elevated on days 1, 5 and 7 after injury while T-4 remained unchanged throughout. While testosterone was decreased over only the first 2 days post-trauma, cortisol was increased over these first 2 days after in jury. In contrast, following severe penetrating injury (GCS 4-6), there wer e significant declines in TSH, T-3 and testosterone over the 7 day observat ion period post trauma. Serum cortisol also declined in these patients betw een 1-3 days after injury, before increasing again on days 5 and 7 after in jury. Following indirect neurotrauma, TSH was slightly decreased immediatel y after trauma but increased to above normal levels on days 5 and 7 post-tr auma. Similarly, T-3 initially declined after injury, but then increased to above normal levels between 5 and 7 days after injury. T-4 and testosteron e remained unchanged over the entire post-traumatic period. Serum cortisol was significantly increased after indirect neurotrauma but only up to day 2 post-trauma. In summary, patients with both direct and indirect traumatic brain injury demonstrated endocrine alterations after trauma, the dynamics of which may be a reflection of the severity of brain damage.