Thyroid emergencies — thyroid storm and myxoedema coma

Also known as Thyroid storm · Thyrotoxic crisis · Myxoedema coma · Myxedema coma · Severe decompensated hypothyroidism

Thyroid storm (the thyrotoxic crisis) is the rare, life-threatening decompensation of thyrotoxicosis producing tachycardia, hyperthermia, agitation, atrial fibrillation and multi-organ failure, graded by the Burch-Wartofsky score (45+ highly suggestive). Myxoedema coma is its mirror: altered status in 88.9 percent with hypothermia, bradycardia, hypoventilation and hyponatraemia. Storm is treated with propranolol 60-80 mg q4h, PTU 500-1,000 mg load then 250 mg q4h, Lugol 8 drops QID 1 hour after thionamide, hydrocortisone 100 mg then 50 mg QID. Myxoedema coma takes hydrocortisone before thyroid replacement with passive rewarming.

high17 referencesUpdated 26 July 202614 min readSource-verified · Oct 2026

Checked against its sources on 13 Oct 2026

The one-line answer

Thyroid storm and myxoedema coma are the two opposite, life-threatening ends of decompensated thyroid disease, and both are clinical diagnoses treated empirically before the thyroid function result returns — no laboratory abnormality is specific to storm, and the scoring is clinical. Storm is the hypermetabolic crisis — tachycardia, hyperthermia, agitation, atrial fibrillation — treated promptly targeting all steps of hormone formation, release and action: beta-blocker, then thionamide, then iodide 1 hour after the antithyroid drug, then hydrocortisone (iodine first deepens the storm). Myxoedema coma is its mirror — altered mental status in 88.9 percent, hypothermia, bradycardia, hypoventilation — treated with hydrocortisone before thyroid replacement and passive rewarming.^[2]^[3]^[13]^[17]

^[8] ^[13]

Meet the patient

A 45-year-old woman with known Graves disease — non-adherent to her carbimazole — arrives with two days of fever, agitation, palpitations, vomiting and diarrhoea. She is diaphoretic, tremulous, tachycardic at 156 in new atrial fibrillation, temperature 39.8, and confused. She has a diffuse goitre and lid lag. The registrar reaches for the thyroid function test and waits.^[1]

That single act — waiting for the result — is the recurring fatal error in both thyroid emergencies. The TFT takes hours the patient may not have. Storm is a clinical diagnosis: score it on Burch-Wartofsky, start the four-pill sequence now, and let the result catch up.^[1]

References17Show

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