What is the recommended dose of iodine (I) in a thyroid storm?

Recommended Dose of Iodine in Thyroid Storm

In thyroid storm, saturated solution of potassium iodide (SSKI) or sodium iodide should be administered as part of a standard drug regimen, typically following thioamide administration. 1

Dosing Recommendations

• Iodine should be administered orally (tablets or Lugol's solution) as soon as possible after diagnosis of thyroid storm 1
• Iodine administration should follow initial thioamide therapy (propylthiouracil or methimazole) to prevent further thyroid hormone synthesis 1
• Standard dosing options include:
  • Saturated solution of potassium iodide (SSKI) 1
  • Sodium iodide (alternative) 1
  • Lugol's solution (alternative) 1

Treatment Algorithm for Thyroid Storm

1. First-line medications:

   • Begin with thioamide (propylthiouracil or methimazole) to block thyroid hormone synthesis 1
   • Follow with iodine preparation to block thyroid hormone release 1
   • Add beta-blocker (unless contraindicated) to control adrenergic symptoms 1
   • Consider dexamethasone to block peripheral conversion of T4 to T3 1

2. Supportive measures:

   • Oxygen administration as needed 1
   • Antipyretics for fever management 1
   • Appropriate cardiac monitoring 1
   • Treat the underlying precipitating cause 1, 2

Special Considerations

• If oral administration is not possible due to gastrointestinal dysfunction, rectal administration of potassium iodide has been shown to be effective with approximately 40% bioavailability 3
• Intravenous sodium iodide solution can be used in cases of severe deficiency when oral/enteral routes are not available 1
• Caution should be exercised in patients with history of iodine allergy, as severe allergic reactions including anaphylaxis have been reported 1

Clinical Evidence and Outcomes

• Recent observational data suggests that early potassium iodide use (within 2 days of admission) may reduce in-hospital mortality specifically in patients with Graves' disease-associated thyroid storm (odds ratio 0.46; 95% CI, 0.25-0.88) 4
• Early potassium iodide use is also associated with shorter hospital stays and lower hospitalization costs compared to delayed or no iodide treatment 4
• Iodine-induced thyrotoxicosis can itself precipitate thyroid storm in some cases, particularly following administration of iodinated contrast media 2, 5

Potential Pitfalls

• Administering iodine before thioamides may worsen thyrotoxicosis by providing substrate for increased hormone synthesis 1
• Excessive iodine intake can induce autoimmune thyroiditis and hypothyroidism in some patients 1
• Signs of iodine toxicity include abdominal pain, metallic taste, coughing, fever, delirium, diarrhea, and vomiting 1
• Post-radioactive iodine thyroid storm is a rare but potentially fatal complication with a mortality rate of approximately 26.3% 6