What is the treatment for Hashimoto's disease?

Treatment of Hashimoto's Disease

The primary treatment for Hashimoto's disease is thyroid hormone replacement therapy with levothyroxine, which should be dosed at approximately 1.6 mcg/kg/day based on ideal body weight. 1, 2, 3

Diagnosis and Pathophysiology

• Hashimoto's disease (chronic autoimmune thyroiditis) is the most common cause of hypothyroidism in iodine-sufficient regions, affecting women 7-10 times more often than men 3
• The disease is characterized by thyroid infiltration by lymphocytes and antibody-mediated autoimmune response through antibodies against thyroid peroxidase (TPOAbs), leading to destruction of thyrocytes 3
• Diagnosis is primarily based on laboratory findings, including elevated TSH and the presence of thyroid autoantibodies; imaging studies are not indicated for the workup of hypothyroidism 4

Clinical Presentation

• Hashimoto's disease can present in three clinical phases:
  • Thyrotoxicosis (Hashitoxicosis) - when stored thyroid hormones are released from destroyed follicles
  • Euthyroidism - when preserved thyroid tissue compensates for destroyed thyrocytes
  • Hypothyroidism - when thyroid hormone production becomes insufficient 3
• Common symptoms of hypothyroidism include fatigue, muscle cramps, constipation, cold intolerance, hair loss, voice changes, weight gain, intellectual slowness, and insomnia 4, 5
• Extra-thyroidal manifestations may affect multiple organ systems including neurological, cardiovascular, dermatological, gastrointestinal, and musculoskeletal systems 6

Treatment Approach

Levothyroxine Replacement

• The standard treatment is levothyroxine (LT4) replacement therapy 1, 2, 3
• Dosing recommendations:
  • Initial dose: 1.6 mcg/kg/day based on ideal body weight for young, healthy patients without cardiac disease 1, 3
  • For older patients or those with cardiac disease, start with lower doses and titrate gradually 2
• Medication administration:
  • Take on an empty stomach, 30-60 minutes before breakfast 2
  • Separate from iron and calcium supplements by at least 4 hours, as these can interfere with levothyroxine absorption 1

Monitoring and Dose Adjustment

• Monitor serum TSH levels 6-8 weeks after any dose change 2
• In patients on stable replacement therapy, evaluate clinical and biochemical response every 6-12 months 2
• Target is normalization of serum TSH levels 2
• Persistent clinical and laboratory evidence of hypothyroidism despite adequate replacement dose may indicate inadequate absorption, poor compliance, or drug interactions 2

Special Considerations

Pregnancy

• For pregnant patients with pre-existing hypothyroidism, measure serum TSH and free-T4 as soon as pregnancy is confirmed and at minimum during each trimester 2
• Maintain serum TSH in the trimester-specific reference range 2
• Pregnancy may require increased levothyroxine dosage; dose adjustments of 12.5 to 25 mcg per day may be needed 2
• Only levothyroxine (not T3) is indicated during pregnancy, as T3 does not sufficiently cross the fetal blood-brain barrier 3

Persistent Symptoms Despite Treatment

• Some patients may have persistent symptoms despite adequate hormone replacement and normal thyroid function tests 7
• A randomized trial showed that total thyroidectomy improved health-related quality of life and fatigue in patients with persistent symptoms despite normal thyroid function on medical therapy 7
• This surgical approach may be considered in selected patients with persistent symptoms, though this is not standard first-line therapy 7

Alternative Therapies

• Selenium supplementation has been studied for Hashimoto's thyroiditis with some evidence suggesting it may reduce antibody levels 5
• However, current evidence is insufficient to recommend routine selenium supplementation in the management of Hashimoto's thyroiditis 5

Potential Complications of Treatment

• Overtreatment with levothyroxine can lead to iatrogenic hyperthyroidism with symptoms such as insomnia 1
• Levothyroxine has a narrow therapeutic index; both overtreatment and undertreatment may have negative effects on multiple body systems 2

Monitoring for Disease Progression

• Regular monitoring of thyroid function is essential as the disease may progress over time 4
• Hashimoto's disease is associated with a 1.6 times higher risk of papillary thyroid cancer and 60 times higher risk of thyroid lymphoma compared to the general population 3