What is the recommended treatment for Hashimoto's thyroiditis?

Treatment of Hashimoto's Thyroiditis

The recommended treatment for Hashimoto's thyroiditis is thyroid hormone replacement therapy with levothyroxine for patients with overt hypothyroidism or persistent TSH levels above 10 mIU/L, even in asymptomatic individuals. 1

Diagnostic Approach

• Diagnosis is based on elevated TSH levels, with or without low free T4, along with the presence of thyroid peroxidase antibodies 1, 2
• Both TSH and FT4 should be measured in symptomatic patients to differentiate between primary and central hypothyroidism 1
• Hashimoto's thyroiditis typically presents with a painless goiter and symptoms of hypothyroidism 2

Treatment Algorithm

For Overt Hypothyroidism (Elevated TSH with Low FT4)

• Initiate thyroid hormone replacement therapy with levothyroxine 1, 3
• Dosing considerations:
  • For patients under 70 years without cardiac disease or multiple comorbidities: calculate dose based on ideal body weight at approximately 1.6 mcg/kg/day 1
  • For patients over 70 years or with cardiac disease/multiple comorbidities: start with lower dose of 25-50 mcg and titrate up gradually 1
• Monitor TSH every 6-8 weeks while titrating hormone replacement to maintain TSH within reference range 1
• Once adequately treated, repeat testing every 6-12 months or with symptom changes 1

For Subclinical Hypothyroidism

• For TSH >10 mIU/L (persistent, measured 4 weeks apart): initiate levothyroxine even if asymptomatic 1
• For TSH between 4.5-10 mIU/L:
  • If symptomatic: initiate levothyroxine 1
  • If asymptomatic: monitor TSH every 4-6 weeks as part of routine care 1

Special Considerations

• If both adrenal insufficiency and hypothyroidism are present, hydrocortisone should be given before thyroid hormone to avoid precipitating an adrenal crisis 4
• Development of low TSH on therapy suggests overtreatment or recovery of thyroid function; dose should be reduced or discontinued with close follow-up 1
• Liothyronine (T3) can be used in patients allergic to desiccated thyroid or thyroid extract derived from pork or beef 3

Treatment Outcomes

• Levothyroxine therapy can decrease thyroid volume in patients with Hashimoto's thyroiditis 5
• Treatment with levothyroxine leads to a decrease in thyroid peroxidase antibody levels in most patients, though antibodies become negative in only a minority of patients (16%) even after long-term treatment 6
• Prophylactic levothyroxine in euthyroid patients with Hashimoto's thyroiditis may reduce antibody levels and prevent thyroid volume increase, but this remains controversial 7

Monitoring

• After initiating therapy, monitor TSH every 6-8 weeks while titrating to goal 1
• Once stable, monitor TSH every 6-12 months or with symptom changes 1
• FT4 can help interpret abnormal TSH levels during therapy, as TSH may take longer to normalize 1

Pitfalls to Avoid

• Do not initiate thyroid hormone replacement in transient hypothyroidism during recovery phase of subacute thyroiditis 3
• Avoid overtreatment leading to iatrogenic hyperthyroidism, which can increase cardiovascular risk, especially in elderly patients 1
• Do not miss central hypothyroidism (low TSH with low FT4), which requires different evaluation and management 1