Treatment of Thyroid Storm
The immediate treatment of thyroid storm requires a combination of propylthiouracil (PTU) or methimazole, potassium iodide, beta-blockers, corticosteroids, and supportive care to prevent mortality. 1, 2
Diagnosis
- Thyroid storm is characterized by fever, tachycardia disproportionate to fever, altered mental status, gastrointestinal symptoms, and cardiac arrhythmias 2
- Do not delay treatment while awaiting laboratory confirmation, as mortality rises significantly with treatment delays 2
Treatment Algorithm
Step 1: Hospitalization and Initial Stabilization
- Immediately hospitalize all patients with thyroid storm, with severe cases requiring ICU admission 2
- Administer supplemental oxygen and position patient in head-up position to improve respiratory function 2
- Increase frequency of observations for patients with suspected thyroid storm 2
Step 2: Block Thyroid Hormone Synthesis
- Administer propylthiouracil (PTU) as first choice since it inhibits both thyroid hormone synthesis and peripheral conversion of T4 to T3 1, 3
- Alternatively, methimazole can be used if PTU is not available 1
- PTU is particularly effective for thyroid storm due to its unique ability to inhibit peripheral conversion of T4 to T3 3
Step 3: Block Thyroid Hormone Release
- Administer saturated potassium iodide solution or sodium iodide 1-2 hours AFTER starting treatment with thionamides 1, 2
- NEVER administer iodine before thionamides, as this can worsen thyrotoxicosis 1, 2
Step 4: Control Adrenergic Effects
- Administer beta-blockers, preferably propranolol at 60-80 mg orally every 4-6 hours, to control tachycardia and other cardiovascular symptoms 1, 4
- For patients with hemodynamic instability, consider using short-acting beta-blockers like esmolol for careful titration 5, 6
- Monitor for potential side effects of beta-blockers including hypotension, bronchospasm, and heart failure 4, 6
Step 5: Reduce Peripheral Conversion of T4 to T3
- Administer dexamethasone or another corticosteroid to reduce peripheral conversion of T4 to T3 and treat potential relative adrenal insufficiency 1, 2
Step 6: Supportive Care
- Provide antipyretics to control fever 1
- Identify and treat precipitating factors (infection, surgery, childbirth, etc.) 1, 7
- Monitor for development of agranulocytosis with thionamide use 5, 2
- Watch for cardiac complications such as heart failure 2
Special Considerations
Pregnancy
- Treatment protocol for pregnant patients is similar to non-pregnant patients 5, 2
- Monitor fetal status and avoid delivery during thyroid storm unless absolutely necessary 5
- Women with Graves' disease should be monitored for normal heart rate and appropriate fetal growth 5
Follow-up and Monitoring
- Close monitoring of thyroid function every 2-3 weeks after initial stabilization 1, 2
- Watch for transition to hypothyroidism, which is common after thyroid storm treatment 1, 2
- Plan definitive treatment of underlying thyrotoxicosis after acute crisis is controlled (continued medical therapy, thyroidectomy, or radioactive iodine ablation) 8
Potential Complications and Pitfalls
- Beta-blockers may exacerbate heart failure in patients with cardiac dysfunction 4, 6
- Abrupt withdrawal of beta-blockers may precipitate thyroid storm 4, 6
- Thionamides can cause rare but serious side effects including agranulocytosis, hepatitis, vasculitis, and thrombocytopenia 5
- Mortality rate of thyroid storm is 10-20% even with appropriate treatment 9
Medication-Specific Considerations
- Propylthiouracil is preferred over methimazole in thyroid storm due to its additional effect of blocking peripheral T4 to T3 conversion 3
- Esmolol is useful in situations requiring rapid control of heart rate with the ability to quickly adjust dosing, particularly in patients with underlying cardiac dysfunction 6
- Beta-blockers may mask certain clinical signs of hyperthyroidism, and abrupt withdrawal might precipitate thyroid storm 4, 6