What is the treatment for toxic goiter in pediatric patients?

Treatment of Toxic Goiter in Pediatric Patients

Antithyroid drugs (ATDs) are the first-line treatment for toxic goiter in pediatric patients, with methimazole being the preferred medication for a duration of 12-18 months. 1, 2, 3

First-Line Treatment: Antithyroid Drugs

• Methimazole (MMI) is the preferred antithyroid medication for pediatric patients with toxic goiter, as it has a better safety profile than propylthiouracil 2, 3
• Propylthiouracil (PTU) should be avoided in children due to the risk of severe liver injury, including liver failure requiring transplantation 4, 2
• The typical treatment duration with antithyroid drugs is 12-18 months 3, 5
• Remission rates with antithyroid drug therapy range from 30-61% after a first course of treatment 6, 3, 5
• Longer duration of ATD treatment (beyond 2 years) may improve remission rates, with recent studies showing 40-50% remission after prolonged treatment 3

Monitoring During ATD Treatment

• Regular monitoring of thyroid function tests (TSH, free T4) is essential to maintain a euthyroid state 4
• Liver function tests should be monitored, particularly with PTU (if used in exceptional circumstances) 4
• Patients should be instructed to report symptoms of potential adverse effects immediately, including fever, sore throat (possible agranulocytosis), rash, or symptoms of hepatic dysfunction 4

Second-Line Treatment Options

Radioactive Iodine (RAI)

• Radioactive iodine is effective but should be avoided in young children (especially under 5 years) due to low-level whole-body radiation exposure 2, 7
• When RAI is administered, dosages should exceed 150 μCi/g of thyroid tissue, with higher doses needed for larger glands 2
• RAI is generally considered for children with poor compliance to ATDs, those not achieving remission after 1-2 years of ATDs, or those experiencing major adverse effects 7

Surgery (Thyroidectomy)

• Total or near-total thyroidectomy is the recommended surgical procedure for toxic goiter in children 8, 7
• Surgery should be considered in specific situations:
  • Children younger than 5 years who don't respond to or experience major adverse effects from ATDs 7
  • Patients with very large goiters 7
  • Cases of poor medication adherence 8
  • When ATDs and RAI are not appropriate options 1
• Complications from thyroidectomy are considerably higher in children than adults, necessitating an experienced thyroid surgeon 2

Risk Factors for Relapse After ATD Treatment

• Severe biochemical hyperthyroidism at diagnosis 5
• Younger age at diagnosis 5
• Non-Caucasian ethnicity 5
• Shorter duration of initial ATD treatment 5

Important Considerations

• Uncontrolled thyrotoxicosis in early childhood can cause irreversible damage to the central nervous system and affect multiple organ systems 7
• Post-thyroidectomy or post-RAI patients will require lifelong levothyroxine therapy 3
• The care of children with toxic goiter is complex and requires physicians with expertise in pediatric thyroid disorders 2

Treatment Algorithm

1. Start with methimazole as first-line therapy for 12-18 months
2. Monitor thyroid function regularly to maintain euthyroid state
3. If remission occurs: continue monitoring for potential relapse
4. If no remission after 12-18 months, poor compliance, or major side effects:
   • For children >5 years: consider radioactive iodine
   • For children <5 years or with large goiters: consider thyroidectomy by an experienced pediatric surgeon