What is the treatment for Hashimoto’s thyroiditis?

Treatment for Hashimoto's Thyroiditis

The primary treatment for Hashimoto's thyroiditis is oral levothyroxine sodium (T4) monotherapy, which should be initiated when patients develop hypothyroidism with elevated TSH levels. 1, 2

Diagnosis and Evaluation

• Hashimoto's thyroiditis is the most common cause of hypothyroidism in the United States 1
• Diagnosis is based on:
  • Elevated TSH level
  • Normal or low free T4 levels
  • Presence of thyroid peroxidase antibodies
  • Often accompanied by a painless goiter 3
• Multiple TSH tests over a 3-6 month interval should be performed to confirm abnormal findings 2

Treatment Algorithm

When to Initiate Treatment

1. Overt Hypothyroidism: Always treat when TSH is elevated with low free T4 2
2. Subclinical Hypothyroidism:
   • Treatment is reasonable as TSH approaches 10 mIU/L 2
   • The median TSH level at initiation of therapy has decreased over time from 8.7 to 7.9 mIU/L 1

Levothyroxine Dosing

• Initial dose calculation: 1.6 mcg/kg/day based on ideal body weight for patients under 70 years without cardiac disease 2
• Special populations:
  • Elderly patients (>70 years) or those with cardiac conditions: Start with 25-50 mcg/day 2
  • Pregnant women: Increase weekly dosage by 30% (take one extra dose twice weekly) once pregnancy is confirmed 2, 4

Administration Guidelines

• Take as a single daily dose on an empty stomach 2
• Separate from medications that may interfere with absorption (calcium, iron, antacids) by at least 4 hours

Monitoring and Dose Adjustment

• Check TSH and free T4 after 6-8 weeks of treatment 2
• Adjust dose in increments of 12.5-25 mcg based on TSH results 2
• Target TSH values: 0.5-2.0 mIU/L for most patients with normal free T4 levels 2
• Once stable, monitor TSH every 6-12 months or if symptoms change 2

Special Considerations

Pregnancy

• Monitor TSH every 4 weeks until stable, then each trimester 4
• Maintain TSH in trimester-specific reference range 4
• Reduce levothyroxine dose to pre-pregnancy levels immediately after delivery 4
• Monitor TSH 4-8 weeks postpartum 4

Euthyroid Hashimoto's Thyroiditis

Research shows mixed results regarding prophylactic treatment:

• Some studies suggest levothyroxine can decrease thyroid volume in euthyroid patients 5, 6
• However, this is not standard practice and guidelines do not routinely recommend treatment for euthyroid patients 1, 2

Evaluating Treatment Response

• Most patients require lifelong therapy 7
• However, approximately 20% of patients may recover thyroid function 8
• Persistent symptoms despite normalized TSH may indicate:
  • Poor medication adherence
  • Drug interactions
  • Other causes of similar symptoms 2

Potential Pitfalls

1. Overtreatment risks: Iatrogenic hyperthyroidism, osteoporosis, fractures, cardiac issues, atrial fibrillation 2, 4
2. Undertreatment risks: Persistent hypothyroid symptoms, adverse effects on quality of life 2
3. Inappropriate combination therapy: Adding T3 (liothyronine) is not recommended as first-line treatment 2
4. Medication interactions: Absorption can be affected by many medications and supplements

By following this treatment algorithm and monitoring protocol, most patients with Hashimoto's thyroiditis can achieve normal thyroid function and symptom relief with appropriate levothyroxine therapy.