Myxoedema Coma

Abstract

Myxoedema coma is an uncommon condition that primarily affects patients with known hypothyroidism who, for some reason, have stopped taking their thyroxine medication. Other causes are longstanding undiagnosed hypothyroidism due to Hashimoto’s thyroiditis or previous treatment with radioiodine for which the patient has stopped attending follow-up. Triggering causes are infections, cerebrovascular insult (CVI), surgery, treatment with sedatives or other psychopharmaceuticals. Frequently, these are elderly patients. The condition is life threatening.

Myxoedema coma does not necessarily involve unconsciousness or coma. Pathophysiologically, progression to myxoedema coma can be regarded as a loss of the regulatory mechanisms initiated to counteract consequences of severe hypothyroidism. This applies particularly to peripheral vasoconstriction, the purpose of which is to maintain body temperature. The triggering factor interrupts this mechanism with resultant circulatory problems and the patient declines further.