What is the treatment for Hashimoto's (Hashimoto's thyroiditis) thyroiditis?

Treatment of Hashimoto's Thyroiditis

Levothyroxine is the standard treatment for Hashimoto's thyroiditis when TSH is elevated above 10 mIU/L or when patients have any degree of TSH elevation with symptoms of hypothyroidism. 1

When to Initiate Treatment

TSH-Based Treatment Algorithm

• Start levothyroxine immediately for TSH >10 mIU/L, regardless of symptoms or free T4 levels, as this carries approximately 5% annual risk of progression to overt hypothyroidism 1

• For TSH 4.5-10 mIU/L with normal free T4 (subclinical hypothyroidism), treatment decisions depend on specific factors:

  • Treat if symptomatic (fatigue, weight gain, cold intolerance, constipation) 1
  • Treat if positive anti-TPO antibodies are present, as progression risk increases to 4.3% per year versus 2.6% in antibody-negative patients 1, 2
  • Treat if pregnant or planning pregnancy, as subclinical hypothyroidism is associated with preeclampsia, low birth weight, and neurodevelopmental effects 3, 1
  • Otherwise, monitor TSH every 6-12 months without treatment 1

• For normal TSH with positive thyroid antibodies alone, no treatment is indicated—only monitoring every 6-12 months 2

Confirmation Before Treatment

• Always confirm elevated TSH with repeat testing after 3-6 weeks, as 30-60% of elevated values normalize spontaneously 1
• Measure both TSH and free T4 to distinguish subclinical (normal T4) from overt (low T4) hypothyroidism 1
• Check anti-TPO antibodies to confirm autoimmune etiology and assess progression risk 1, 2

Levothyroxine Dosing Strategy

Initial Dosing

• For patients <70 years without cardiac disease: Start with full replacement dose of approximately 1.6 mcg/kg/day 1

• For patients >70 years or with cardiac disease/multiple comorbidities: Start with lower dose of 25-50 mcg/day and titrate gradually to avoid cardiac complications 1

• For pregnant women: Levothyroxine requirements typically increase 25-50% above pre-pregnancy doses, requiring proactive dose adjustments 1

Dose Adjustments

• Increase dose by 12.5-25 mcg increments based on patient age and cardiac status 1
• Use smaller increments (12.5 mcg) for elderly patients or those with cardiac disease 1
• Larger adjustments may lead to overtreatment and should be avoided 1

Monitoring Protocol

During Dose Titration

• Recheck TSH and free T4 every 6-8 weeks after any dose adjustment, as this represents the time needed to reach steady state 1
• Target TSH within reference range (0.5-4.5 mIU/L) with normal free T4 levels 1

After Stabilization

• Monitor TSH every 6-12 months once adequately treated on stable dose 1
• Recheck sooner if symptoms change or clinical status changes 1

Additional Treatment Considerations

Goiter Reduction

• Levothyroxine treatment can decrease thyroid volume in patients with goitrous Hashimoto's thyroiditis by approximately 32% over 24 months 4, 5
• The effect on goiter size is related to normalization of thyroid function but unrelated to changes in antibody levels 4
• In children with euthyroid Hashimoto's, levothyroxine can reduce thyroid volume, though the effect is limited to a definite time period 6

Alternative Formulations

• Levothyroxine sodium oral solution (containing only levothyroxine, water, and glycerol) may be beneficial for patients with malabsorption issues, gastroparesis, or small intestinal bacterial overgrowth (SIBO) 7
• Liothyronine can be used in patients allergic to desiccated thyroid or thyroid extract derived from pork or beef 8

Critical Safety Considerations

Before Starting Treatment

• Rule out concurrent adrenal insufficiency before initiating levothyroxine, as starting thyroid hormone before corticosteroids can precipitate life-threatening adrenal crisis 1
• In suspected central hypothyroidism or hypophysitis, always start physiologic dose steroids 1 week prior to thyroid hormone replacement 1

Risks of Overtreatment

• Approximately 25% of patients are inadvertently maintained on excessive doses that fully suppress TSH, increasing risks for: 1

  • Atrial fibrillation and cardiac arrhythmias (especially in elderly)
  • Osteoporosis and fractures (especially in postmenopausal women)
  • Abnormal cardiac output and ventricular hypertrophy
  • Increased cardiovascular mortality

• If TSH becomes suppressed (<0.1 mIU/L) on therapy, reduce levothyroxine dose by 25-50 mcg immediately 1

Common Pitfalls to Avoid

• Never treat based on a single elevated TSH value without confirmation, as transient elevations are common 1, 2
• Never start treatment based solely on positive antibodies with normal thyroid function, as this leads to unnecessary lifelong treatment 2
• Avoid adjusting doses too frequently before reaching steady state—wait 6-8 weeks between adjustments 1
• Never assume hypothyroidism is permanent without reassessment—consider transient thyroiditis, especially in recovery phase 1
• Don't overlook non-thyroidal causes of TSH elevation, such as recent iodine exposure, acute illness, or recovery from severe illness 1