Treatment of Levothyroxine Poisoning in Children
The treatment of levothyroxine poisoning in children should focus on gastrointestinal decontamination with activated charcoal as the primary intervention, with symptomatic management of tachycardia using beta-blockers when clinically indicated.
Initial Management
Gastrointestinal Decontamination
- Activated charcoal: Administer 1 g/kg as soon as possible after ingestion 1
- Most effective if given within 1-2 hours of ingestion
- Single dose is typically sufficient; serial dosing is not necessary 2
Clinical Assessment
- Vital signs monitoring with particular attention to:
- Heart rate (tachycardia is the most common symptom)
- Blood pressure
- Temperature (fever may develop)
- Obtain baseline thyroid function tests:
- Free T4
- Free T3
- TSH
Symptomatic Management
For Tachycardia/Hypertension
- Propranolol is the beta-blocker of choice for symptomatic tachycardia 3, 4
- Pediatric dosing: 0.01-0.1 mg/kg/dose every 6-8 hours
- Titrate to control heart rate
- Continue until thyroid hormone levels normalize
For Fever
- Acetaminophen for temperature >38.5°C 1
- Standard pediatric dosing based on weight
For Severe Symptoms (rare)
- In cases with seizures, severe tachycardia, or altered mental status:
- Consider ICU admission for close monitoring
- Supportive care as indicated
Monitoring Requirements
Hospital Observation
- Children with any of the following should be monitored in hospital for at least 48-72 hours 4:
- Levothyroxine dose >0.1 mg/kg
- Symptomatic presentation
- Free T4 >100 pmol/L
- Short interval between ingestion and presentation
Outpatient Follow-up
- For less severe cases, outpatient monitoring for 14 days 4
- Check thyroid function tests at:
- 1-2 weeks post-ingestion
- 4-6 weeks post-ingestion
Expected Clinical Course
Most cases of levothyroxine poisoning in children follow a benign course 2, 5:
- Symptoms typically develop 24 hours after ingestion 3, 1
- Common symptoms include tachycardia, fever, irritability, and hyperactivity 5
- Resolution of elevated free T4 occurs by approximately 12 days post-ingestion 1
- Normalization of TSH may take up to 7 weeks 1
Important Considerations
- Do not use routine prophylactic treatment with propylthiouracil, corticosteroids, or cholestyramine in asymptomatic patients 2
- Do not perform dialysis or hemoperfusion as these are not effective for levothyroxine removal 2
- Contact Poison Control Center (1-800-222-1222) for current management recommendations 6
Potential Complications to Monitor
- Seizures (rare but reported in children) 6
- Cardiac arrhythmias
- Transient symptoms that may persist for weeks:
- Desquamation of palms and soles
- Hair loss
- Irritability 1
Despite reports of severe complications in some cases, the vast majority of pediatric levothyroxine ingestions result in mild symptoms that resolve with supportive care and do not require aggressive interventions beyond activated charcoal and symptomatic management.