What is the treatment for Hashimoto's disease?

Treatment of Hashimoto's Disease

The primary treatment for Hashimoto's disease is levothyroxine (LT4) replacement therapy, which should be initiated when TSH exceeds 10 mIU/L or when patients are symptomatic with TSH levels between 4.5-10 mIU/L.

Diagnosis and Clinical Presentation

Hashimoto's thyroiditis (HT) is a common autoimmune disorder characterized by thyroid infiltration by lymphocytes and antibody-mediated autoimmune response through antibodies against thyroid peroxidase (TPOAbs). The clinical presentation varies:

1. Thyrotoxicosis (Hashitoxicosis): When stored thyroid hormones are released from destroyed thyroid follicles
2. Euthyroidism: When preserved thyroid tissue compensates for destroyed thyrocytes
3. Hypothyroidism: When thyroid hormone production becomes insufficient 1

Diagnosis is confirmed through:

• Elevated TSH with normal or low free T4
• Presence of thyroid peroxidase antibodies (TPOAbs)
• Typical hypoechogenicity on thyroid ultrasound

Treatment Algorithm

1. Hypothyroid Patients

• Initial Dosing: Levothyroxine at 1.4-1.8 mcg/kg/day based on degree of preserved thyroid function and lean body mass 1
• Dose Adjustment: Titrate dose based on TSH levels, checked 6-8 weeks after any dose change 2
• Monitoring: Once stable, check TSH and free T4 every 6-12 months 3

2. Subclinical Hypothyroidism (TSH elevated, normal free T4)

• TSH > 10 mIU/L: Start levothyroxine therapy 3
• TSH 4.5-10 mIU/L with symptoms: Trial of levothyroxine, continuing only if clear symptomatic benefit occurs 3
• TSH 4.5-10 mIU/L without symptoms: Consider monitoring without treatment, especially in younger patients

3. Euthyroid Patients with Positive Antibodies

• With goiter: Consider levothyroxine therapy which may reduce goiter size and slow disease progression 4
• Without goiter: Monitor TSH every 6-12 months as these patients have increased risk of developing hypothyroidism 5

Special Populations

Pregnant Women

• Pre-existing hypothyroidism: Increase levothyroxine dose by 12.5-25 mcg/day as soon as pregnancy is confirmed 2
• Monitor: Check TSH and free T4 every trimester at minimum 2
• Target: Maintain TSH in trimester-specific reference range 2
• Postpartum: Reduce dose to pre-pregnancy levels immediately after delivery 2

Pediatric Patients

• Initial monitoring: Check TSH and free T4 at 2 and 4 weeks after treatment initiation 2
• Ongoing monitoring: Every 3-12 months after dose stabilization until growth is completed 2
• Clinical assessment: Regular evaluation of development, mental and physical growth, and bone maturation 2

Treatment Efficacy and Expectations

• Levothyroxine therapy reduces TPO antibody levels in 92% of patients, with an average decrease of 45% after 1 year and 70% after 5 years 6
• Only about 16% of patients will have complete normalization of antibody levels even after long-term treatment 6
• Thyroid function monitoring is essential as 43% of initially euthyroid patients may develop hypothyroidism within 18 months 5

Potential Complications and Monitoring

• Overtreatment: About 25% of patients on levothyroxine are unintentionally maintained on doses that fully suppress TSH 3
• Cardiovascular risks: TSH suppression increases risk of atrial fibrillation and cardiovascular mortality, particularly in patients >60 years 3
• Bone health: TSH suppression can lead to bone mineral density loss in postmenopausal women 3
• Thyroid cancer risk: Hashimoto's thyroiditis is associated with 1.6 times higher risk of papillary thyroid cancer 1

Surgical Considerations

Surgery (subtotal thyroidectomy) may be considered for patients with:

• Persistent large goiter causing compression symptoms despite long-term levothyroxine treatment
• Cosmetic concerns due to goiter size
• Nodular lesions requiring evaluation for malignancy 7

Key Practice Points

• Regular monitoring of thyroid function is essential even in euthyroid patients with Hashimoto's thyroiditis
• Levothyroxine is the standard treatment; there is insufficient evidence to recommend combination therapy with T3 except in specific cases 1
• In pregnancy, only levothyroxine is indicated as T3 does not sufficiently cross the fetal blood-brain barrier 1
• Prophylactic treatment with levothyroxine in euthyroid Hashimoto's patients may reduce both serological and cellular markers of autoimmune thyroiditis 4