Evaluation of postmortem serum and cerebrospinal fluid levels of thyroid-stimulating hormone with special regard to fatal hypothermia

The aim of the present study was to undertake, during routine forensic work, a comprehensive analysis of the serum and cerebrospinal fluid (CSF) levels of thyroid-stimulating hormone (TSH) and to examine hypophyseal TSH immunopositivity in relation to the cause of death, with particular regard to fatal hypothermia. Medicolegal autopsy cases (n = 120; within 48 h postmortem; survival time, <24 h), including cases of blunt injury (n = 9), sharp instrument injury (n = 8), fire fatality (n = 18), mechanical asphyxiation (n = 10), drowning (n = 21), poisoning (n = 6), hypothermia (n = 10), and acute ischemic heart disease (n = 38), were examined. Serum and CSF TSH concentrations were measured using an electrochemiluminescence immunoassay. TSH immunoreactivity in adenohypophysis was quantitatively analyzed. Serum and CSF TSH levels were significantly lower in cases of hypothermia than in the other groups (p < 0.05 and p < 0.001, respectively). TSH immunopositivity in adenohypophysis was significantly lower in cases of hypothermia, but exhibited a large case-to-case variation for poisoning. These observations suggest that a decrease in serum and CSF TSH levels in hypothermia is related to hypothalamic adenohypophyseal dysfunction.