thyroid storm

Introduction

Extreme manifestation of thyrotoxicosis. Life-threatening complication of hyperthyroidism.

Etiology

• precipitating factors*
  • infection (most common)
  • surgical stress or anesthesia
  • sudden withdrawal of thionamide (PTU, methimazole)
  • large doses of I-131 given to severely thyrotoxic patient with large goiter
    • generally occurs within 7-10 days post therapy
  • myocardial infarction
  • iodine contained in contrast agents for radiographic studies (angiography) in patients with Graves disease
  • parturition, labor & delivery
• untreated Graves disease*

* most commonly Graves disease in combination with preciptating factor(s)

Epidemiology

• rare

Pathology

• acute release of preformed hormone
• no correlation between level of circulating level of T4 & severity of symptoms

Clinical manifestations

• acutely ill patient with exacerbated symptoms of thyrotoxicosis, hyperthyroidism
• fever > 100 degrees F
• tachycardia > 120/min, atrial fibrillation, heart failure
• hypotension, shock
• abdominal pain, nausea, vomiting, diarrhea
• jaundice
• lid lag &/or signs/symptoms of Graves ophthalmopathy
• delirium, psychosis
• seizures, apathy, stupor & coma as condition worsens
• elderly patients may lack hyperkinetic features & present with lethargy & cardiac manifestations only
• patients on beta blockers may have blunted manifestations

Laboratory

• see hyperthyroidism
• increased free T4, free T3 (most important test after low serum TSH)
• abnormal liver function tests

* clinical diagnosis; no level of thyroxine is diagnostic

Complications

• mortality 15-20% with treatment
• mortality may be as high as 30%

Management

• decrease conversion of T4 -> T3
  • use IV propranolol in ICU
  • propylthiouracil (methimazole does not do this)
  • dexamethasone (4-8 mg/day)
• decrease release of thyroid hormone
  • saturated solution of KI (SSKI): 5-10 drops in water
  • Lugol's solution: 5-10 drops
  • 1 g NaI IV over 8-10 hours
• treat associated adrenal dysfunction
  • hydrocortisone
• treat associated thermoregulatory dysfunction
  • cooling blanklets
  • acetamionphen
• treat precipitating factors
• reverse systemic decompensation
• lithium carbonate is rarely used
• poor outcome is associated with:
  • circulatory collapse
  • obtundation
  • jaundice (in absence of CHF)
• plasmapheresis
  • evidence supporting use of plasmapheresis is from case reports
    • generally reserved for patients in whom standard therapy has failed

More general terms

• thyrotoxicosis

Additional terms

• hyperthyroidism