Treatment of Thyroid Storm
Thyroid storm requires immediate multi-drug therapy without waiting for laboratory confirmation, as mortality rises significantly with treatment delays and can reach 75% if treatment is postponed. 1, 2, 3
Immediate Treatment Algorithm
Step 1: Block Thyroid Hormone Synthesis (Start First)
- Administer propylthiouracil (PTU) 500-1000 mg loading dose, then 250 mg every 4 hours as the preferred first-line agent because it uniquely inhibits both thyroid hormone synthesis AND peripheral conversion of T4 to T3 4, 2, 5
- Alternatively, use methimazole 20 mg every 4-6 hours if PTU is unavailable, though it lacks the peripheral conversion blocking effect 1, 4, 6
- Critical timing: Never administer iodine before thionamides are on board, as this can worsen thyrotoxicosis 4, 2
Step 2: Block Thyroid Hormone Release (1-2 Hours After Thionamides)
- Administer saturated solution of potassium iodide (SSKI) 5 drops every 6 hours, OR sodium iodide 500-1000 mg IV every 8 hours 1, 4, 2
- Alternative options include Lugol's solution or lithium if iodine is contraindicated 1
Step 3: Control Adrenergic Symptoms
- Propranolol 60-80 mg orally every 4-6 hours is the preferred beta-blocker because it also blocks peripheral T4 to T3 conversion in addition to controlling cardiovascular symptoms 4, 2, 7
- For hemodynamically unstable patients requiring vasopressor support: Use esmolol with loading dose of 500 mcg/kg IV over 1 minute, then maintenance infusion starting at 50 mcg/kg/min, titrating up to maximum 300 mcg/kg/min 1, 4
- If beta-blockers are contraindicated (severe heart failure, bronchospasm): Use diltiazem 15-20 mg (0.25 mg/kg) IV over 2 minutes, then 5-15 mg/h maintenance infusion 1, 4
Step 4: Reduce Peripheral T4 to T3 Conversion
- Administer dexamethasone 2 mg IV every 6 hours (also treats possible relative adrenal insufficiency) 1, 4
Essential Supportive Care
- Aggressive IV fluid resuscitation with large-bore access 2
- Oxygen therapy as needed 1, 4, 2
- Antipyretics for fever control (avoid aspirin as it increases free thyroid hormone levels) 1, 4, 2
- Identify and treat precipitating factors: infection, surgery, trauma, labor/delivery, medication non-adherence 1, 2, 8
Hospitalization Requirements
- All patients require hospitalization; severe cases mandate ICU admission 4, 2
- Obtain immediate endocrinology consultation 2
- Continuous cardiac monitoring with serial vital signs every 5-15 minutes during initial stabilization 4
Critical Monitoring
- Monitor for agranulocytosis with thionamide use (presents with sore throat and fever; obtain CBC and discontinue drug immediately if suspected) 1, 2
- Watch for cardiac complications including heart failure, arrhythmias, and atrial fibrillation 1, 4, 2
- Monitor for hypotension, bradycardia, and bronchospasm with beta-blocker use 4, 7
- Serial thyroid function tests every 2-3 weeks after stabilization, watching for transition to hypothyroidism (common after treatment) 4, 2
Special Populations: Pregnancy
- Treatment protocol is identical to non-pregnant patients 1, 2
- Monitor fetal status with ultrasound, nonstress testing, or biophysical profile based on gestational age 1, 2
- Avoid delivery during thyroid storm unless absolutely necessary due to high maternal and fetal mortality risk 1, 2
- Thyroid storm affects <1% of pregnant women with hyperthyroidism but carries extremely high risk 2
Alternative Routes When Oral Access Unavailable
- Intravenous methimazole (available in Europe and Japan, not in the United States) 9
- Rectal administration via enema or suppository of propylthiouracil or methimazole can be compounded when patient is NPO 9
Refractory Cases
- Consider therapeutic plasma exchange for patients who fail to respond to conventional therapy within 12-24 hours 10, 8, 3
- Early thyroidectomy should be considered if medical treatment fails to produce clinical improvement, as mortality may reach 75% without intervention 3