What is the management of intraoperative thyroid storm?

Management of Intraoperative Thyroid Storm

Immediate recognition and aggressive management of intraoperative thyroid storm is critical to prevent mortality, requiring a systematic approach targeting hormone synthesis, release, and peripheral effects while providing supportive care.

Initial Recognition and Assessment

• Suspect thyroid storm when encountering unexplained intraoperative tachycardia and hypertension, especially in patients with known or suspected hyperthyroidism 1
• Monitor for classic manifestations including hyperthermia, tachycardia out of proportion to anesthetic depth, hypertension, and cardiac arrhythmias 2
• Differentiate from other intraoperative emergencies such as malignant hyperthermia or pheochromocytoma crisis 1
• Assess for organ dysfunction, as thyroid storm can affect multiple systems including cardiovascular, neurological, and gastrointestinal systems 2

Immediate Management

• Call for help immediately and notify the surgical team to expedite procedure completion if possible 3
• Position patient with head elevated to optimize airway patency if not contraindicated by surgical procedure 3
• Administer supplemental oxygen and ensure adequate ventilation 3
• Establish additional large-bore IV access for medication administration 2
• Begin continuous cardiac monitoring and frequent vital sign checks 2

Pharmacological Intervention (Multi-targeted Approach)

1. Block Thyroid Hormone Synthesis

• Administer thionamides as first-line therapy:
  • Propylthiouracil (PTU): 600-1000 mg loading dose followed by 200-250 mg every 4-6 hours via nasogastric tube 4
  • PTU preferred over methimazole in thyroid storm due to additional effect of blocking T4 to T3 conversion 4

2. Block Thyroid Hormone Release

• Administer iodine solutions 1-2 hours AFTER thionamides to prevent increased hormone synthesis:
  • Potassium iodide (SSKI): 5 drops every 6 hours via nasogastric tube, OR
  • Lugol's solution: 10 drops every 8 hours via nasogastric tube 4

3. Block Peripheral Effects of Thyroid Hormone

• Administer beta-blockers to control cardiovascular manifestations:
  • Propranolol: 1-2 mg IV slowly, repeated every 15 minutes until heart rate controlled (maximum 10 mg) 4
  • Esmolol: 50-100 μg/kg/min continuous infusion for more titratable control 2
  • Consider cardioselective beta-blockers (e.g., metoprolol) in patients with bronchospastic disease 4

4. Corticosteroid Therapy

• Administer high-dose corticosteroids to reduce T4 to T3 conversion and treat potential relative adrenal insufficiency:
  • Hydrocortisone: 100 mg IV every 8 hours 4, 2

5. Supportive Therapy

• Aggressive cooling measures for hyperthermia:
  • Cooling blankets, ice packs, and cold IV fluids 2
• Treat precipitating factors if identified 4
• Maintain adequate hydration with IV fluids 2
• Correct electrolyte abnormalities, particularly monitoring for hypercalcemia 2
• Consider dextrose infusion to prevent hypoglycemia from increased metabolic demands 2

Management of Complications

Cardiovascular Complications

• For cardiogenic shock (associated with high mortality):
  • Initiate vasopressors as needed 2
  • Consider echocardiography to assess cardiac function 2
  • In severe cases unresponsive to conventional therapy, consider extracorporeal membrane oxygenation (ECMO) 2

Refractory Cases

• Consider therapeutic plasma exchange for cases unresponsive to conventional therapy:
  • Rapidly removes circulating thyroid hormones 5
  • Can be life-saving in patients with storm refractory to standard treatments 5

Post-Crisis Management

• Continue anti-thyroid medications and supportive care 4
• Monitor closely for recurrence of thyroid storm 2
• Transfer to ICU for continued management and monitoring 2
• Plan for definitive treatment of underlying thyrotoxicosis once stabilized 4

Critical Considerations and Pitfalls

• Mortality remains high (17-22%) even with appropriate treatment, particularly in patients developing cardiogenic shock 2
• Multiple organ failure significantly impacts prognosis, necessitating aggressive management 2
• Failure to recognize thyroid storm intraoperatively can lead to delayed treatment and worse outcomes 1
• Amiodarone use is a common precipitating factor for thyroid storm and should be noted in patient history 2
• Discontinuation of anti-thyroid medications preoperatively can precipitate thyroid storm 2