Treatment of myxoedema coma--factors associated with fatal outcome.

Treatment of myxoedema coma has been associated with a high mortality. The causes of death were analysed in this paper by retrospective study of the records of 11 myxoedema coma patients. The serum thyroxine (T4) and triiodothyronine (T3) levels were estimated retrospectively from the amounts of hormone given to the patients by a two-compartment model. Seven patients died and 4 survived. The patients who died were significantly older (78.9 +/- 2.2 years, mean +/- SEM) than those who survived (66.8 +/- 3.7 years). The initial heart rate was lower in the decreased group, but both groups had increased their heart rate on treatment. The surviving patients showed an increase in body temperature during the first 3 days of treatment, in contrast to the patients who eventually died. The deceased patients had received larger amounts of thyroid hormone and had calculated levels of T3 that were nearly twice as high as those of the surviving patients. Old age and a high serum level of T3 are determinants for the fatal outcome of myxoedema coma. Our analysis underscores the importance of using a cautious replacement regimen in myxoedema coma patients.