Dynamic observation on thyroid function in severe head injury.

The dynamic changes of thyroid hormone levels in patients with severe head injury were observed. The results showed that the serum thyroid hormone levels changed rapidly within several hours after the injury and the mean levels of serum total T3 and T4 (TT3, TT4) decreased while high reverse triiodothyronine (rT3) increased significantly. Serum TT3, TT4 and rT3 levels returned to normal gradually in 2 to 3 weeks after the injury in the surviving group, whereas serum total T4 gradually declined and rT3 steadily increased in the fatal group. The mean levels of serum TSH remained unchanged in both groups. Therefore, the use of the levels of serum thyroid hormones as adjuvant indices can be helpful in making pertinent judgements of the severity and prognosis of severe head injuries.