What are the symptoms and treatment of thyroid storm?

Symptoms and Treatment of Thyroid Storm

Clinical Presentation

Thyroid storm is a life-threatening medical emergency characterized by severe acute exacerbation of hyperthyroidism with multiorgan decompensation. 1

Cardinal Symptoms

The diagnosis is based on a combination of clinical features including:

• Fever - often out of proportion to other findings 1, 2
• Tachycardia - disproportionate to the degree of fever 1, 2
• Altered mental status - ranging from nervousness and agitation to confusion, delirium, or even coma 1, 2
• Cardiovascular manifestations - including signs of congestive heart failure, arrhythmias, and hemodynamic instability 2, 3
• Gastrointestinal symptoms - vomiting, diarrhea, nausea, and hepatic dysfunction with possible jaundice 2, 3, 4

Additional Clinical Features

• Exaggerated hyperthyroid symptoms - tremors, excessive sweating, heat intolerance, and hyperactivity 1, 2
• Weight loss and hyperactivity 5
• Evidence of multiorgan decompensation distinguishes thyroid storm from uncomplicated thyrotoxicosis 2

Treatment Algorithm

Immediate Stabilization (First Hour)

Treatment must begin immediately based on clinical suspicion without waiting for laboratory confirmation, as mortality rises significantly with treatment delays. 6, 7

Step 1: Block Thyroid Hormone Synthesis

• Administer propylthiouracil (PTU) first - this is the preferred agent because it inhibits both thyroid hormone synthesis AND peripheral conversion of T4 to T3 6, 7, 8
• Methimazole is an alternative if PTU is unavailable 6

Step 2: Block Thyroid Hormone Release (1-2 Hours After Thionamides)

• Administer saturated potassium iodide solution or sodium iodide 1-2 hours AFTER starting thionamides 6, 7
• Critical pitfall: NEVER give iodine before thionamides, as this can worsen thyrotoxicosis 6, 7

Step 3: Control Adrenergic Symptoms

• Propranolol 60-80 mg orally every 4-6 hours is the first-line beta-blocker because it also blocks peripheral T4 to T3 conversion 6, 7
• Esmolol is preferred for hemodynamically unstable patients due to its rapid onset (within 1 hour) and short half-life allowing careful titration 6
• Avoid beta-blockers in severe heart failure 6

Step 4: Reduce Peripheral T4 to T3 Conversion

• Administer dexamethasone or another corticosteroid to reduce peripheral conversion and treat potential relative adrenal insufficiency 6, 7

Supportive Care

• Provide oxygen therapy as needed 6
• Administer antipyretics (avoid aspirin as it can increase free thyroid hormone) 6
• Aggressive fluid resuscitation with large-bore IV access 7
• Identify and treat precipitating factors - infection, surgery, trauma, childbirth, diabetic ketoacidosis, iodine exposure 6, 3, 4

Hospitalization and Monitoring

• All patients require hospitalization; severe cases need ICU admission 6, 7
• Obtain immediate endocrinology consultation 6
• Monitor for cardiac complications including heart failure and arrhythmias 6, 7
• Monitor for agranulocytosis with thionamide use (presents with sore throat and fever) 1, 7
• Monitor coagulation parameters if coagulopathy is suspected 7

Alternative Therapies (When Standard Treatment Fails)

• Cholestyramine can be considered to enhance thyroid hormone elimination 6, 8
• Lithium carbonate or potassium perchlorate in certain refractory cases 8

Special Populations

Pregnancy

• Treatment protocol is identical to non-pregnant patients 6, 7
• Monitor fetal status closely 6, 7
• Avoid delivery during thyroid storm unless absolutely necessary 6
• Thyroid storm affects less than 1% of pregnant women with hyperthyroidism but carries high maternal and fetal risk 1

Follow-Up

• Monitor thyroid function every 2-3 weeks after initial stabilization 6, 7
• Watch for transition to hypothyroidism, which commonly occurs after thyroid storm treatment 6, 7
• Plan definitive treatment (radioactive ablation or surgery) once the acute crisis resolves 8, 4

Important Diagnostic Considerations

• Clinical diagnosis is paramount - do not wait for laboratory confirmation to initiate treatment 2, 3
• No single laboratory value establishes the diagnosis 2
• Burch-Wartofsky point scale and Japan Thyroid Association criteria can assist in diagnosis 2
• Consider mimics including sympathomimetic overdose, alcohol withdrawal, sepsis, serotonin syndrome, and heat stroke 2