Hyperthyroid crisis (thyrotoxic storm)

Do not wait for test results if urgent treatment is needed.

Investigations

• TSH, free T4, free T3.
• Confirm with technetium uptake if possible.

Management

1. IV access, fluids if dehydrated.
2. NG tube if vomiting
3. Take blood for: T3, T4, TSH, cultures (if infection suspected)
4. Sedate if necessary (e.g. chlorpromazine 50mg oral/IM). Monitor BP
5. If no contraindication, and cardiac output OK, give propranolol 60mg/4–6h oral;
   • max IV dose: 1mg over 10min;
   • may need repeating every few hours.
   • In asthma/poor cardiac output, propranolol has caused cardiac arrest in thyroid storm, so ultra-short-acting β-blockers have a role, e.g. IV esmolol.
   • Consider diltiazem if β-blockers contraindicated.
6. High-dose digoxin may be needed to slow the heart, but ensure adequately β-blocked, give with cardiac monitoring
7. Antithyroid drugs: carbimazole 15–25mg/6h oral (or via NGT); after 4h give Lugol’s solution (aqueous iodine oral solution) 0.3mL/8h oral well diluted in water for 7–10d to block thyroid
8. Hydrocortisone 100mg/6h IV or dexamethasone 2mg/6h oral to prevent peripheral conversion T4 to T3
9. Treat suspected infection, e.g. with co-amoxiclav 1.2g/8h IV
10. Adjust IV fluids as necessary; cool with tepid sponging ± paracetamol
11. If you are not making headway in 24h, thyroidectomy may be an option.
12. Continuing treatment:
    1. After 5d reduce carbimazole to 15mg/8h oral.
    2. After 10d stop propranolol and iodine. Adjust carbimazole