Thyroid hormones in comatose patients with traumatic brain injury

The objective was to study if thyroid hormones, cortisol, prolactin and brain injury marker levels were changed in traumatic brain injury (TBI) patients with changing levels of consciousness. We estimated the above named parameters in 32 patients (27 men and 5 women aged 11-55). Admission Glasgow Coma Score was < 8. Follow-up period--30 days. The length of coma was 3 to 25 days. There were significant decreases in TSH, TBG, FT3 and F_levels (p < 0.05, for each) and a T3 increase (as compared to very low preceding values) on day 1 before emergence from coma and considerable post-coma increase in TBG, FT3, TSH and F levels (p < 0.001 each) on days 1-3 in patients with diffuse axonal injury (DAI). In patients with contusions and epidural and subdural hematomas (CH) T3 and T4 levels continued to fall until 4-6 postcoma days. TSH values significantly increased up to average normal ranges (p < 0.05) on days "-" 2 and "-" 1 before emergence from coma and remained so. Significantly lower levels of TSH, F and PRL were found in patients with CH in the mostly remote period (on days "-" 12-"-" 8) before emergence from coma in comparison with DAI patients. In blood the following correlations of examined parameters were established: between NSE and T3 (r = -0.39), NSE and FT3 (r = -0.59), TNF alpha and TBG (r = -0.64), TNF alpha and T3 (r = -0.3) and S-100 and T3 (r = -0.3) (p < 0.05, for each). The results obtained confirmed a low T3 syndrome in comatose TBI patients. We demonstrated an objective and informative interdependence: the turning-point moment of the emergence from coma was accompanied by significant changes of examined hormone levels and brain injury marker levels. The results may serve as a base for recommending monitoring FT3 and T3 levels simultaneously with that of other injury markers and adequate T3 replacement therapy in the early posttraumatic period.