Alterations in thyroid hormones in brain-dead patients are related to non-thyroidal illness syndrome

Alterations in thyroid hormone levels occur in patients with acute neurological disease states. The aim of this study is to study changes in thyroid hormones in patients with brain death (BD).

Eleven brain-dead patients were studied prospectively. Thyroid hormones were measured on admission to the intensive care unit, the day before BD diagnosis (BD before), and the day after BD diagnosis (BD day).

Thyroid stimulating hormone (TSH) and free triiodothyronine (fT3) concentrations were found to be significantly low on ad-mission, BD before, and BD day compared to age-matched healthy controls. TSH levels were shown to be increasing on BD day. Free thyroxine (fT4) levels were within normal limits in all cases except in one case having low fT4 levels with normal TSH levels. No statisti-cally significant changes were encountered between admission thyroid hormone levels and BD-before and BD-day thyroid hormone levels. Six patients were on steroid therapy when BD-before blood samples were drawn, and no difference in thyroid hormone levels was encountered between steroid users and non-users. Correlation analysis showed a positive correlation between GCS and TSH, but a negative association between fT3 and APACHE II.

We have shown that patients with BD have altered thyroid hormones days before BD diagnosis, and these alterations con-tinue until the diagnosis of BD. The changes in thyroid hormones are compatible with non-thyroidal illness syndrome.