Agitated, temperature 40 °C, AF at 160/min, vomiting, jaundice — two weeks after stopping carbimazole
ABCDE
Both ends of the thyroid spectrum are clinical diagnoses treated before the assay returns. Storm: block the hormone, block the receptor, block conversion, then cool and support. Myxoedema: warm, ventilate, and give steroid before thyroxine.
Thyroid storm — recognise it → fever, tachyarrhythmia out of proportion, agitation or coma, vomiting and diarrhoea, and cardiac failure in a patient with known or suspected thyrotoxicosis; apply the Burch-Wartofsky score but treat on clinical suspicion
Storm — treat in this order → propranolol 1 mg IV increments (or esmolol infusion) first; then propylthiouracil 500–1000 mg loading, 250 mg 4-hourly; then iodine (Lugol's or potassium iodide) at least 1 hour AFTER the thionamide; then hydrocortisone 100 mg IV 6-hourly
Storm — support → active cooling and paracetamol (never aspirin, which displaces hormone from its binding protein), fluid and glucose, treat the precipitant — infection, surgery, iodinated contrast, amiodarone, drug withdrawal or DKA
Myxoedema coma → hypothermia, bradycardia, hypoventilation with CO₂ retention, hyponatraemia, hypoglycaemia and a depressed conscious level; ventilate, rewarm passively, and correct sodium and glucose slowly
Myxoedema — hormone and steroid → give hydrocortisone 100 mg IV FIRST, then levothyroxine 200–400 µg IV loading followed by 50–100 µg daily (lower in the elderly and in ischaemic heart disease), with or without liothyronine; thyroxine before steroid can precipitate adrenal crisis
Order set
- TSH, free T4, free T3, cortisol before steroid
- FBC, U&E, glucose, LFT, CK, blood cultures
- ECG and continuous cardiac monitoring
- Cooling measures; avoid aspirin
- Hydrocortisone 100 mg IV
- Search for the precipitant (infection, contrast, amiodarone, non-adherence)
- Arterial or venous gas in suspected myxoedema
Criteria
AdmitAny suspected storm or myxoedema coma
ICUArrhythmia with instability, heart failure, coma, hypoventilation, or temperature above 40 °C
DischargeEuthyroid trajectory, precipitant treated, endocrinology follow-up and definitive plan agreed
Clinical detail — differentials, red flags, pitfalls, disposition
Red flags
- Temperature above 40 °C with atrial fibrillation
- New heart failure in thyrotoxicosis
- Hypothermia with bradycardia and CO₂ retention
- Hyponatraemia below 120 mmol/L with a depressed conscious level
Differentials
- Sepsis
- Sympathomimetic or anticholinergic toxidrome
- Neuroleptic malignant syndrome and serotonin syndrome
- Heat stroke
- Adrenal crisis
- Hypothermia from exposure
- Sedative overdose
Common mistakes
- Giving iodine before the thionamide, which fuels hormone synthesis
- Using aspirin to cool a storm
- Giving levothyroxine before hydrocortisone in myxoedema
- Rewarming actively and causing vasodilated shock
- Waiting for the thyroid function result before treating
Disposition & follow-up
Endocrinology involvement from the first hour; definitive treatment — radioiodine or surgery for thyrotoxicosis, lifelong replacement for hypothyroidism — is planned before discharge.
Discharge package
MedicationsThionamide or levothyroxine with a clear adherence plan; beta-blocker taper
Follow-upEndocrinology within 2–4 weeks with thyroid function tests
LifestyleNever stop antithyroid or replacement therapy without advice; sick-day rules
Warning symptomsPalpitations, fever, weight change, severe fatigue, drowsiness, sore throat on carbimazole
💊 Treatment detail — doses & preparation
Propylthiouracilthionamide
Dose500–1000 mg oral/NG loading, then 250 mg every 4 h; switch to carbimazole once stable
PreparationTablets, crushed via NG if needed
MonitorLFTs (hepatotoxicity), FBC for agranulocytosis
Lugol's iodine / potassium iodideiodine
Dose5–10 drops every 8 h, starting at least 1 h after the thionamide
PreparationDiluted in water or juice
MonitorNever give first — it increases hormone synthesis in an unblocked gland
Levothyroxine (myxoedema)thyroid hormone
Dose200–400 µg IV loading, then 50–100 µg IV daily; lower dose in the elderly or with coronary disease
PreparationIV preparation; oral absorption is unreliable in myxoedema
MonitorECG, heart rate, sodium, glucose; give hydrocortisone first
📖 ATA thyrotoxicosis and hypothyroidism guidelines · ICU chapter 64 · Thyroid Storm & MyxedemaReviewed September 2026