What are the symptoms and treatment of thyroid storm?

Symptoms and Treatment of Thyroid Storm

Thyroid storm is a life-threatening hypermetabolic emergency characterized by fever, tachycardia out of proportion to the fever, altered mental status, vomiting, diarrhea, and cardiac arrhythmias, requiring immediate treatment to prevent shock, stupor, and coma. 1

Clinical Presentation of Thyroid Storm

Key Diagnostic Features

• Fever: Often high-grade, a hallmark symptom
• Cardiovascular manifestations:
  • Tachycardia disproportionate to fever
  • Cardiac arrhythmias
  • Heart failure signs
  • Hypotension in severe cases
• Neurological symptoms:
  • Altered mental status (nervousness, restlessness, confusion)
  • Agitation
  • Seizures
  • Progression to stupor and coma if untreated
• Gastrointestinal symptoms:
  • Vomiting
  • Diarrhea
  • Abdominal pain
• Hepatic dysfunction 1, 2

Precipitating Factors

Thyroid storm typically occurs in the presence of an identifiable trigger such as:

• Infection
• Surgery
• Trauma
• Labor/delivery
• Iodine exposure
• Radioactive iodine treatment
• Medication non-compliance 1, 2, 3

Diagnosis

Diagnosis is primarily clinical, as laboratory values may not differ significantly from uncomplicated hyperthyroidism. Waiting for laboratory confirmation can dangerously delay treatment 4.

Diagnostic Criteria

• Burch-Wartofsky Point Scale: Clinical scoring system
• Japan Thyroid Association Diagnostic Criteria 2

Laboratory Assessment

• Suppressed TSH
• Elevated free T4 and T3 levels
• Additional tests to evaluate organ dysfunction:
  • Complete blood count
  • Liver function tests
  • Renal function tests 1, 2

Treatment Algorithm

Immediate Management (First Hour)

1. Resuscitation and supportive care:

   • Oxygen, IV fluids, cooling measures
   • Treat the precipitating factor (e.g., antibiotics for infection)

2. Medication administration:

   • Thioamides: Propylthiouracil (preferred in thyroid storm due to its additional benefit of blocking T4 to T3 conversion) 5

     • Initial dose: 600-1000 mg loading, then 200-250 mg every 4-6 hours

   • Beta-blockers: Propranolol (unless severe heart failure present) 6

     • 60-80 mg orally every 4-6 hours or 1-2 mg IV slowly

   • Corticosteroids: Dexamethasone 2-4 mg IV every 6 hours

   • Iodine solution: Begin 1 hour AFTER thioamide administration

     • Options: Saturated solution of potassium iodide, sodium iodide, or Lugol's solution

3. Additional therapies:

   • Cholestyramine for bile acid sequestration
   • Antipyretics for fever management (avoid aspirin which can increase free thyroid hormone)
   • Sedation for agitation: Phenobarbital 1, 2

Refractory Cases

For patients not responding to conventional therapy:

• Consider therapeutic plasma exchange 7
• Early thyroidectomy if medical management fails 4

Monitoring and Follow-up

• Continuous cardiac monitoring
• Frequent vital sign checks
• Serial mental status assessments
• Electrolyte monitoring
• Consider ICU admission 2

Common Pitfalls and Caveats

1. Delayed diagnosis: Thyroid storm can mimic other conditions including:

   • Sepsis/septic shock
   • Sympathomimetic overdose
   • Alcohol withdrawal
   • Heat stroke
   • Serotonin syndrome 2

2. Treatment delays: Do not wait for laboratory confirmation before initiating treatment in a clinically suspicious case 4

3. Medication sequencing: Always administer thioamides BEFORE iodine preparations to prevent increased hormone synthesis 1

4. Beta-blocker caution: Use with care in heart failure; consider calcium channel blockers as alternatives in severe cases 3

5. Multidisciplinary approach: Early involvement of critical care and endocrinology specialists is crucial 2

Thyroid storm carries a mortality rate of 10-20% even with treatment, highlighting the importance of rapid recognition and aggressive management 4.