AKA Hyperthyroid Crisis or Thyroid storm
Presents as a life threatening exacerbation of Hyperthyroidism.Despite early recognition and treatement, mortality is still 10 % and upto 30% when presents with Hyperthermia, Cardiac failure and arrhythmia.
Precipitating Factors of Thyrotoxic Crisis-
- Acute illness (e.g. stroke, infection, trauma, Diabetic Ketoacidosis or DKA)
- Surgery (especially subtotal thyroidectomy when patient is ill-prepared)
- Radioiodine treatment of a patient with partially treated or untreated hyperthyroidism.
- Atrial fibrillation
- Heart Failure
Management requires ICU monitoring , Identification and treatment of the precipitating cause, and measures that reduce thyroid hormone synthesis
- Rehydation , cooling, and oxygen.
- Broad-Spectrum Antibiotics to prevent infection
- Large doses Propylthiouracil (600 mg loading dose followed by 200–300 mg every 6 hrly) given orally or by nasogastric tube or per rectum; the drug’s inhibitory action on T4 to T3 conversion makes it the antithyroid drug of choice. 1 hour after the 1st dose of propylthiouracil, stable iodide is given . It blocks T3T4 synthesis via the Wolff-Chaikoff effect (the delay allows the antithyroid drug to prevent the excess iodine from being incorporated into new hormone).( Harrison’s Principle of Internal Medicine)
- Propanolol- rapidly at 80mg 6 hrly oral or IV 1-5mg 6 hrly. reduce tachycardia and other adrenergic manifestations. high doses of propranolol decrease T4 to T3 conversion
- Carbimazole- useful in incooperative patients. Can be used per rectally at 40-60mg daily.
- Sodium Iopodate 500mg per day orally. It restores T3 levels to normal in 48-72 hours and reduces peripheral conversion of T4 to T3 which is active form.\
- Potassium Iodide or Lugol’s Iodine- Not preferred now.
- Dexamethasone- 2 mg 6 hrly
- Amiodarone.?? Also Read about Hypothyoidism
A case Study- Case
Article by Dr. Sujit Shrestha ( References- Harrison’s Principle of Int. Med., Davidsons Principle and Practice of Med., Online sources)