What is the treatment for Hashimoto's thyroiditis?

Treatment of Hashimoto's Thyroiditis

The definitive treatment for Hashimoto's thyroiditis is levothyroxine therapy for patients with overt hypothyroidism (TSH >10 mIU/L or elevated TSH with low free T4), while those with normal thyroid function (euthyroid) should be monitored without immediate medication. 1

Diagnosis and Monitoring

• Diagnosis is confirmed through:

  • TSH and free T4 measurements
  • Positive thyroid peroxidase (TPO) antibodies indicating autoimmune etiology
  • Multiple tests over 3-6 months to confirm abnormal findings 1

• Monitoring recommendations:

  • For patients with positive antibodies but normal thyroid function: TSH and free T4 every 1-2 years
  • For patients on levothyroxine: TSH levels 6-8 weeks after dose changes, then every 6-12 months once stable 1

Treatment Algorithm

1. Overt Hypothyroidism

• Initiate levothyroxine therapy when:
  • TSH >10 mIU/L, or
  • Elevated TSH with low free T4 1

2. Subclinical Hypothyroidism

• Consider levothyroxine for:
  • Women who are pregnant or planning pregnancy
  • Patients with clear symptoms attributable to hypothyroidism 1

3. Euthyroid Hashimoto's

• Monitor TSH and free T4 every 1-2 years
• No medication needed unless thyroid function deteriorates 1, 2

Dosing Guidelines

Population	Starting Dose	Target TSH Range
Adults <70 years without cardiac disease	1.6 mcg/kg/day	0.5-2.0 mIU/L
Elderly or patients with cardiac conditions	25-50 mcg/day	1.0-4.0 mIU/L
Pregnant women	Adjust to restore TSH to reference range	Trimester-specific reference range

1, 3

Special Considerations

Pregnancy

• For pre-existing hypothyroidism: measure TSH and free T4 as soon as pregnancy is confirmed and each trimester
• Increase dose by 12.5-25 mcg/day as needed to maintain trimester-specific TSH range
• Return to pre-pregnancy dose immediately after delivery 3

Children

• Start at one-fourth the recommended full replacement dosage
• Increase weekly by one-fourth until full replacement dose is reached
• Monitor TSH and free T4 at 2 and 4 weeks after initiation, 2 weeks after any dose change, then every 3-12 months 3, 4

Monitoring for Complications

• Screen for other autoimmune conditions:

  • Particularly celiac disease
  • Consider when diabetes is present (can cause unexplained hypoglycemia) 1

• Watch for overtreatment signs:

  • Low TSH levels associated with increased cardiovascular risk
  • Atrial fibrillation (3-fold increased risk in adults ≥60 years with TSH ≤0.1 mIU/L)
  • Osteoporosis, especially in elderly patients 1

Clinical Course and Prognosis

Hashimoto's thyroiditis typically follows a progressive course, with most patients eventually developing hypothyroidism requiring lifelong levothyroxine therapy 2, 5. While levothyroxine effectively manages the hypothyroidism, it does not alter the underlying autoimmune process, as evidenced by persistent antibody levels 6.

Common Pitfalls to Avoid

1. Failing to differentiate Hashimoto's from other forms of thyroiditis

   • Unlike subacute or postpartum thyroiditis, Hashimoto's rarely has a hyperthyroid phase and typically leads to permanent hypothyroidism 2, 5

2. Overtreatment with excessive levothyroxine

   • Can increase risk of atrial fibrillation and osteoporosis
   • Target appropriate TSH range based on age and cardiac status 1

3. Attributing non-specific symptoms to Hashimoto's

   • Patients often have symptoms not fully explained by thyroid dysfunction
   • Consider screening for associated autoimmune conditions 7

4. Inadequate follow-up

   • Even euthyroid patients with positive antibodies require regular monitoring
   • Poor compliance with medication is common and requires assessment 1, 3