Introduction
Myxoedema coma is a life-threatening complication of hypothyroidism.
It follows a background of long-standing
hypothyroidism.
Clinical features of myxoedema coma
Myxoedema coma may be precipitated by exposure to cold, infection, trauma and central nervous system suppressants
- Coma with extreme hypothermia,
temperatures 24 – 32ºC - Seizures
- Areflexia
- CO retention and respiratory depression due to decreased cerebral blood flow
Differential diagnoses
- Coma due to CNS depressants
- Adrenal insufficiency
- Morbid depression
Complications of myxoedema coma
- Cardiac failure
- Respiratory failure
- Death
Investigations
- T3 (triiodothyronine) assay
- T4 (thyroxine) assay
- Thyroid stimulating hormone (TSH) assay
Treatment for myxoedema coma
Treatment objectives
- To restore normal body metabolism
- To prevent death
Drug treatment
- Triiodothyronine 20 µg
intravenously stat,- then 20 micrograms every 8 hours until there is sustained clinical improvement
- May also require hydrocortisone 100 mg intravenously every 8 hours
- Maintain therapy with oral thyroxine in a dose of 50 µg per day
- Treat precipitating factor(s)
Precaution
- Patients should not be re-warmed rapidly because of risk of cardiac arrhythmias