Characterization of plasma magnesium concentration and oxidative stress following graded traumatic brain injury in humans.

Plasma magnesium, calcium, and oxidative status were investigated in 31 male casualties with traumatic brain injury (TBI) during a 7-day posttraumatic period. The study group consisted of eight patients with mild closed head injury (Glasgow Coma Scale score [GCS] of 13-15), 10 patients with extensive penetrating head injury (GCS 4-6), and 13 patients with blast injuries but without direct head trauma. The latter group was included since previous experimental and clinical data have confirmed the development of indirect brain trauma in patients with blast injuries. Patients with multiple injuries were not included. Significant declines in plasma divalent cations were found in GCS 4-6 patients immediately after TBI and persisting for the entire 7-day study period. Similar changes in magnesium, but not calcium, were present in the GCS 13-15 and the blast injury groups, but only up until day 3 after injury. Alterations in lipid peroxidation products and superoxide anions were also observed following TBI. Increased lipid peroxidation was noted in all three groups over the entire posttraumatic period while increases in superoxide anion generation occurred transiently immediately following TBI. Thereafter, in the GCS 13-15 and blast injury groups, superoxide anions subsequently normalized, whereas in extensive head injury (GCS 4-6), superoxide anion generation significantly declined. A negative correlation between magnesium balance and oxidative stress was observed in all patients immediately after injury persisting in GCS 4-6 patients to the end of the observation period. Our findings suggest an interrelationship between magnesium changes and blood oxidants/antioxidants after TBI, which could be of both diagnostic and prognostic value in patients with neurotrauma.

Neuroendocrine responses following graded traumatic brain injury in male adults.

In an effort to characterize thyroid, gonadal and adrenal function following neurotrauma, the present study determined serum concentrations of thyroid-stimulating hormone (TSH), total triiodothyronine (T3), thyroxine (T4), 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 penetrating head injury (GCS 4-6) and 13 patients with blast injuries but without 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. Following mild injury (GCS 13-15), TSH was increased up until day 3 after injury. T3 levels were elevated on days 1, 5 and 7 after injury while T4 remained unchanged throughout. While testosterone was decreased over only the first 2 days post-trauma, cortisol was increased over these first 2 days after injury. In contrast, following severe penetrating injury (GCS 4-6), there were significant declines in TSH, T3 and testosterone over the 7 day observation period post-trauma. Serum cortisol also declined in these patients between 1-3 days after injury, before increasing again on days 5 and 7 after injury. Following indirect neurotrauma, TSH was slightly decreased immediately after trauma but increased to above normal levels on days 5 and 7 post-trauma. Similarly, T3 initially declined after injury, but then increased to above normal levels between 5 and 7 days after injury. T4 and testosterone 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.