Thyroid Storm (Thyrotoxic Crisis)

Thyroid storm is a life-threatening decompensation of thyrotoxicosis with a mortality of 10–30%. Diagnose clinically using the Burch-Wartofsky score (≥45 = highly suggestive). Treatment uses four simultaneous drug classes in strict sequence…

Burch-Wartofsky Score / BTA / ETA Guidelines

The pathway

1 · Recognise and score — Burch-Wartofsky

Temperature: >41°C = 30 pts, 39–40.9°C = 20 pts, 38–38.9°C = 10 pts
CNS effects: seizure/coma = 30 pts, psychosis/extreme irritability = 20 pts, mild agitation = 10 pts
GI effects: jaundice = 20 pts, diarrhoea/nausea/vomiting = 10 pts
Heart rate: >140 = 25 pts, 120–139 = 20 pts, 110–119 = 15 pts
CHF: pulmonary oedema = 25 pts, peripheral oedema = 5 pts
AF: 10 pts
Precipitant: yes = 10 pts
Score ≥45: thyroid storm (ITU). 25–44: impending storm. <25: unlikely.

2 · Step 1 — Thionamide (block synthesis)

Propylthiouracil (PTU) 200mg PO/NG every 4 hours (preferred — also blocks T4→T3 conversion)
If PTU unavailable: carbimazole 20–40mg PO/NG every 4 hours
Must be given FIRST before iodine
NG route if GCS reduced or vomiting

3 · Step 2 — Iodine (block release) — at least 1 hour after thionamide

Lugol's iodine: 0.3ml (= 8 drops) TDS in water or juice
If unavailable: potassium iodide 60mg every 6 hours
Wait at least 1 hour after first thionamide dose — iodine given before thionamide risks worsening storm (Jod-Basedow effect)
Continue for 7–10 days

4 · Step 3 — Beta-blocker (symptom control)

Propranolol 60–80mg PO every 4–6 hours — also blocks T4→T3 conversion
IV: propranolol 1mg IV over 1 minute, repeat every 5 min up to 5mg (ITU/monitoring only)
If asthma/COPD: diltiazem as alternative (check cardiology)
Target HR <100 bpm
Do NOT use beta-blocker first — control block-release axis first

5 · Step 4 — Corticosteroids (reduce T4→T3 and treat relative insufficiency)

Hydrocortisone 100mg IV every 8 hours
Reduces peripheral conversion of T4 to T3
Treats relative adrenal insufficiency common in thyroid storm
Continue for 5–7 days, then taper

6 · Supportive care

Active cooling: paracetamol, cooling blanket, ice packs to axillae and groin
DO NOT use aspirin (displaces thyroid hormone from protein → worsens storm)
IV fluids: large volume loss from sweating/fever
Thiamine 100mg IV if alcohol or nutritional concern
Cardiac monitoring: AF very common — digoxin or rate control per cardiology
Thromboprophylaxis (high VTE risk)
Treat precipitant: antibiotics if sepsis, surgery if obstructed

7 · Identify and treat precipitant

Infection: most common — septic screen + antibiotics
Iodine load (contrast, amiodarone): review drug history
Thyroid surgery or radioiodine (recent)
Trauma, MI, PE — investigate accordingly
Medication non-adherence: review antithyroid drug history

Drugs

Drug	Dose	Route	Notes
Propylthiouracil (PTU)	200mg PO/NG every 4 hours	PO or NG	First drug given. Blocks synthesis AND T4→T3 conversion. Give before iodine. NG route if vomiting.
Lugol's Iodine	0.3ml (8 drops) TDS	PO in water	At least 1 hour after PTU — giving before thionamide worsens storm. Continue 7–10 days.
Propranolol	60–80mg every 4–6h PO; 1mg IV slowly in ITU	PO or IV	Blocks T4→T3 conversion. Target HR <100. Avoid in asthma — use diltiazem instead.
Hydrocortisone	100mg IV every 8 hours	IV	Reduces T4→T3 conversion. Treats relative adrenal insufficiency. Continue 5–7 days, then taper.
Paracetamol	1g PO/IV every 6 hours	PO or IV	Antipyretic of choice. Do NOT use aspirin — displaces thyroid hormone from protein binding.

When to escalate

Burch-Wartofsky ≥45 — ITU admission, endocrinology on-call, ITU consultant review,GCS falling — airway management, ITU, CT head to exclude other cause,Refractory AF with haemodynamic instability — cardiology input, consider DC cardioversion post-rate control,Liver failure (jaundice, coagulopathy) — hepatology input; PTU carries hepatotoxicity risk — switch to carbimazole if prolonged use,High-output cardiac failure — echo, cardiology, consider plasmapheresis in extreme refractory cases,No thyroid hormone levels available — treat empirically if Burch-Wartofsky ≥45, do not wait for results

Reference: Burch-Wartofsky Scoring System / British Thyroid Association Emergency Guidelines / ETA Guidelines 2016

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