What is the recommended management for thyroid storm?

Management of Thyroid Storm

Thyroid storm requires immediate, aggressive multi-drug therapy with propylthiouracil (or methimazole), potassium iodide administered 1-2 hours after thionamides, beta-blockers, corticosteroids, and intensive supportive care to prevent mortality rates of 20-50%. 1, 2, 3

Immediate Treatment Algorithm

Step 1: Block New Thyroid Hormone Synthesis (Start First)

Propylthiouracil (PTU) is the preferred first-line agent because it uniquely inhibits both thyroid hormone synthesis AND peripheral conversion of T4 to T3, making it superior to methimazole in thyroid storm. 1, 2, 4

• PTU dosing: Loading dose of 600-1000 mg orally, then 200-250 mg every 4 hours 1
• Methimazole alternative: 20-25 mg every 4 hours if PTU unavailable 1, 2
• Critical pitfall: Monitor for PTU-induced agranulocytosis and hepatotoxicity throughout treatment, as these can be life-threatening even at low doses 1, 2

Step 2: Block Thyroid Hormone Release (Wait 1-2 Hours After Step 1)

Administer saturated solution of potassium iodide (SSKI) or sodium iodide 1-2 hours AFTER starting thionamides. 1, 2, 5

• Timing is critical: Never give iodine before thionamides, as this will worsen thyrotoxicosis by providing substrate for new hormone synthesis 1, 2
• SSKI dosing: 5 drops (250 mg) orally every 6 hours 1

Step 3: Control Cardiovascular Symptoms

Beta-blockers are essential for controlling tachycardia and preventing cardiovascular collapse. 1, 2

For Hemodynamically Stable Patients:

• Propranolol 60-80 mg orally every 4-6 hours (preferred because it also blocks T4 to T3 conversion) 1

For Hemodynamically Unstable Patients or Those on Vasopressors:

• Esmolol is the beta-blocker of choice due to its ultra-short half-life allowing rapid titration 1
• Esmolol dosing: Loading dose 500 mcg/kg (0.5 mg/kg) IV over 1 minute, then maintenance infusion starting at 50 mcg/kg/min, titrating up to maximum 300 mcg/kg/min 1
• Monitoring during esmolol: Continuous cardiac monitoring, blood pressure and heart rate every 5-15 minutes during titration, watch for hypotension, bradycardia, and heart failure 1

If Beta-Blockers Contraindicated:

• Diltiazem 15-20 mg (0.25 mg/kg) IV over 2 minutes, then 5-15 mg/h maintenance infusion 1
• Note: Digoxin is ineffective in thyroid storm due to high adrenergic tone 1

Step 4: Reduce Peripheral T4 to T3 Conversion

Dexamethasone 2 mg IV/PO every 6 hours to block peripheral conversion and treat potential relative adrenal insufficiency 1, 2

Supportive Care (Simultaneous with Above)

• Aggressive IV hydration and electrolyte management 1
• Antipyretics for fever control (avoid aspirin as it displaces thyroid hormone from binding proteins) 1, 2
• Oxygen therapy as needed 1, 2
• Identify and treat precipitating factors: infection, surgery, trauma, medication noncompliance 1, 2, 6

Hospitalization Requirements

All patients with thyroid storm require ICU admission with immediate endocrine consultation. 1, 2

• Continuous cardiac monitoring required 1
• Monitor for cardiac complications including heart failure and arrhythmias 1, 2

Clinical Parameters for Dose Adjustment

Indicators for PTU Dose Reduction:

• Heart rate normalization to <90-100 bpm 1
• Temperature control with fever <38.5°C 1
• Improvement in mental status (resolution of agitation, confusion) 1
• Cardiovascular stabilization (improved cardiac output, resolution of arrhythmias) 1

Indicators for Dose Escalation:

• Worsening confusion, development of seizures, progression to stupor or coma 1

Special Situations

Pregnancy

Use the same aggressive treatment protocol as maternal mortality risk outweighs fetal concerns. 1, 2, 5

• PTU is preferred over methimazole in first trimester due to methimazole's teratogenicity 1
• Monitor fetal status with ultrasound, nonstress testing, or biophysical profile 1
• Avoid delivery during active thyroid storm unless absolutely necessary, as delivery can precipitate or worsen the storm 1, 2, 5

Alternative Routes if NPO

• Rectal administration of PTU via enema if oral route unavailable 7
• IV methimazole available in Europe and Japan but not in the United States 7

Refractory Cases

For patients failing conventional therapy or with cardiovascular collapse:

• Therapeutic plasma exchange can rapidly reduce circulating thyroid hormone levels 8
• VA-ECMO support as bridge to stabilization and definitive treatment in patients with multiorgan failure and cardiac arrest 6
• Emergency thyroidectomy after initial stabilization in extreme cases 6, 7

Post-Acute Management

• Monitor thyroid function every 2-3 weeks after initial stabilization to catch transition to hypothyroidism, which commonly occurs after thyroid storm treatment 1, 2
• Switch from PTU to methimazole after storm resolution due to PTU's significant hepatotoxicity risk with prolonged use (methimazole safer for long-term maintenance and can be dosed once daily) 1
• Plan definitive treatment of underlying thyrotoxicosis: continued medical therapy, thyroidectomy, or radioactive iodine ablation 2

Critical Pitfalls to Avoid

• Never delay treatment while waiting for laboratory confirmation - thyroid storm is a clinical diagnosis 2
• Never administer iodine before thionamides - this worsens thyrotoxicosis 1, 2, 5
• Never continue PTU indefinitely after storm resolution due to cumulative hepatotoxicity risk 1
• Never use aspirin as antipyretic - it displaces thyroid hormone from binding proteins 2