What is the treatment for thyroid storm, including dosages of medications such as propylthiouracil (PTU) and propranolol?

Treatment of Thyroid Storm with Medication Dosages

The treatment of thyroid storm requires immediate administration of propylthiouracil (PTU) at an initial dose of 300-400 mg daily divided in 3 equal doses, along with propranolol for adrenergic symptom control, potassium iodide, and corticosteroids to prevent mortality. 1, 2, 3

First-Line Medications and Dosages

1. Thionamides to Block Hormone Synthesis

• Propylthiouracil (PTU) is the preferred first-line agent as it inhibits both thyroid hormone synthesis and peripheral conversion of T4 to T3 1, 3
  • Initial dose: 300 mg daily (divided into 3 equal doses at 8-hour intervals) 3
  • For severe hyperthyroidism: 400-600 mg daily; occasionally up to 900 mg daily may be required 3
  • Maintenance dose: 100-150 mg daily 3
• Alternatively, methimazole can be used if PTU is unavailable 1

2. Beta-Blockers to Control Adrenergic Effects

• Propranolol is the most widely studied nonselective beta-blocker for thyroid storm 4, 1
  • Advantages: Blocks peripheral conversion of T4 to T3 in addition to controlling adrenergic symptoms 4, 1
  • Typical dosing: 60-80 mg orally every 4-6 hours 1
• For hemodynamic instability, consider esmolol (short-acting IV beta-blocker) for rapid titration 1
  • Allows careful control of heart rate with ability to quickly adjust dosing 1

3. Iodine Solutions to Block Hormone Release

• Administer saturated potassium iodide solution or sodium iodide 1-2 hours AFTER starting thionamides 1, 2
• CRITICAL: Never administer iodine before thionamides as this can worsen thyrotoxicosis 1, 2

4. Corticosteroids to Reduce T4 to T3 Conversion

• Dexamethasone or another corticosteroid to reduce peripheral conversion of T4 to T3 1, 2
• Also treats possible relative adrenal insufficiency 1, 2, 5
• Premature discontinuation of corticosteroids may lead to recurrence of thyroid storm 5

Treatment Algorithm

1. Immediate Stabilization

   • Hospitalize all patients; severe cases require ICU admission 1, 2
   • Administer supplemental oxygen as needed 2
   • Position patient with head elevated to improve respiratory function 2

2. Medication Administration Sequence

   • First: Administer PTU to block hormone synthesis 1, 2, 3
   • Second: Administer beta-blockers to control cardiovascular symptoms 1, 2
   • Third: Administer iodide solution (1-2 hours after thionamides) 1, 2
   • Fourth: Administer corticosteroids 1, 2

3. Supportive Care

   • Antipyretics for fever control 1
   • Identify and treat precipitating factors (infection, surgery, etc.) 1
   • IV fluids for hydration 1

Special Considerations and Potential Complications

Cardiovascular Complications

• Caution with beta-blockers in patients with heart failure or cardiogenic shock 6
• Rare cases of cardiovascular collapse following propranolol administration have been reported 6
• Monitor for cardiac complications such as heart failure 1, 2

Refractory Cases

• For patients who fail conventional therapy, therapeutic plasma exchange may be considered 7, 8
• Plasma exchange can remove T3 and T4 bound to albumin, autoantibodies, and cytokines 7

Pregnancy Considerations

• Treatment protocol is similar to non-pregnant patients 1, 2
• Monitor fetal status and avoid delivery during thyroid storm unless absolutely necessary 1, 2

Pediatric Dosing

• PTU is generally not recommended for pediatric patients except in rare instances 3
• If necessary for children ≥6 years: Start at 50 mg daily with careful upward titration based on clinical response and thyroid function tests 3

Monitoring and Follow-up

• Increase frequency of vital sign monitoring for patients with thyroid storm 2
• Monitor for development of agranulocytosis with thionamide use 1, 2
• Close monitoring of thyroid function every 2-3 weeks after initial stabilization 1
• Watch for transition to hypothyroidism, which is common after thyroid storm treatment 1

Definitive Treatment

• Plan definitive treatment of underlying thyrotoxicosis after acute crisis is controlled 2
• Options include continued medical therapy, thyroidectomy, or radioactive iodine ablation 2, 9