What is the treatment for Hashimoto's disease?

Treatment of Hashimoto's Disease

Levothyroxine therapy is the cornerstone of treatment for Hashimoto's disease when hypothyroidism develops, with the primary goal of normalizing TSH levels to prevent complications and improve quality of life. 1, 2

Understanding Hashimoto's Disease

Hashimoto's thyroiditis is a chronic autoimmune disorder where lymphocytic infiltration and antibody-mediated destruction (primarily anti-thyroid peroxidase antibodies) progressively damage the thyroid gland. 3 It is the most common cause of hypothyroidism in industrialized nations, affecting women 7-10 times more frequently than men. 4, 3

The disease presents in three clinical phases that determine treatment approach:

• Hashitoxicosis: Transient hyperthyroidism from release of stored hormones during thyroid destruction 3
• Euthyroidism: Compensated phase where remaining thyroid tissue maintains normal hormone levels 3
• Hypothyroidism: Insufficient thyroid hormone production requiring replacement therapy 3

When to Initiate Treatment

Overt Hypothyroidism

Start levothyroxine immediately for any patient with elevated TSH and low free T4, regardless of symptoms. 1, 2

Subclinical Hypothyroidism (Elevated TSH, Normal Free T4)

Initiate levothyroxine therapy for TSH persistently >10 mIU/L, even if asymptomatic, as this carries approximately 5% annual risk of progression to overt hypothyroidism. 1

For TSH 4.5-10 mIU/L, treatment decisions require more nuance:

• Treat if symptomatic (fatigue, weight gain, cold intolerance, constipation) 1
• Treat if positive anti-TPO antibodies, which confer 4.3% annual progression risk versus 2.6% in antibody-negative patients 1
• Treat if pregnant or planning pregnancy, as subclinical hypothyroidism increases risk of preeclampsia, low birth weight, and potential neurodevelopmental effects 1, 2
• Monitor without treatment if asymptomatic with TSH rechecks every 6-12 months 1

Critical Pre-Treatment Assessment

Before starting levothyroxine, confirm elevated TSH with repeat testing after 3-6 weeks, as 30-60% of elevated values normalize spontaneously. 1 Never initiate thyroid hormone in patients with suspected adrenal insufficiency without first starting corticosteroids, as this can precipitate adrenal crisis. 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 based on ideal body weight. 1, 2

For patients >70 years or with cardiac disease/multiple comorbidities: Start conservatively at 25-50 mcg/day and titrate gradually to avoid cardiac decompensation. 1 Elderly patients with coronary disease are at increased risk of unmasking or worsening cardiac ischemia even with therapeutic levothyroxine doses. 1

For pregnant patients with pre-existing hypothyroidism: Increase pre-pregnancy dose by 25-50% immediately upon pregnancy confirmation, as levothyroxine requirements increase during early pregnancy. 1, 5

Dose Adjustments

Adjust levothyroxine in 12.5-25 mcg increments based on current dose and patient characteristics. 1 Larger adjustments risk overtreatment, particularly in elderly or cardiac patients. 1

Recheck TSH and free T4 every 6-8 weeks after any dose change until target TSH (0.5-4.5 mIU/L) is achieved. 1, 5 Once stable, monitor every 6-12 months or when symptoms change. 1

Administration Considerations

Separate levothyroxine from iron and calcium supplements by at least 4 hours, as these interfere with absorption. 2 Take levothyroxine on an empty stomach, preferably 30-60 minutes before breakfast. 5

Managing Persistent Symptoms Despite Euthyroidism

A substantial proportion of Hashimoto's patients experience persistent symptoms despite achieving biochemical euthyroidism on levothyroxine monotherapy. 6 This may relate to reduced FT3/FT4 ratio or persistently elevated antibody titers. 6

For selected patients with persistent symptoms on adequate LT4 monotherapy, consider trial of combined LT4/LT3 therapy, though robust selection criteria remain undefined and this approach requires careful monitoring. 6 Escalation of LT4 monotherapy beyond what normalizes TSH is discouraged due to unfavorable risk-benefit profile. 6

In refractory cases, total thyroidectomy has demonstrated sustained improvements in health-related quality of life compared to medical therapy, though this must be balanced against perioperative risks. 6

Adjunctive Nutritional Management

Address common nutritional deficiencies in Hashimoto's patients, including selenium, vitamin D, zinc, iron, and B vitamins. 7, 8 Selenium supplementation (200 mcg daily) may modestly reduce antibody titers and improve symptoms. 6, 8

Consider lactose elimination if intolerant, as lactose can interfere with levothyroxine absorption. 7 Evaluate for gluten sensitivity, as gliadin may interact with thyroid antigens; gluten-free diet may benefit some patients even without celiac disease. 7, 8

Ensure adequate but not excessive iodine intake—both deficiency and excess can exacerbate autoimmune thyroid disease. 8

Monitoring Disease Progression

Monitor TSH and anti-TPO antibodies periodically. 9 In pediatric studies, levothyroxine therapy significantly decreased anti-thyroglobulin antibody levels over time and may positively affect disease course. 9

Euthyroid patients not on therapy require TSH monitoring every 6-12 months, as approximately 43% develop subclinical or overt hypothyroidism within 18 months. 9

Critical Risks to Avoid

Overtreatment with levothyroxine occurs in 14-21% of treated patients and increases risk for atrial fibrillation, osteoporosis, fractures, abnormal cardiac output, and ventricular hypertrophy. 1 Approximately 25% of patients are unintentionally maintained on doses sufficient to fully suppress TSH. 1

TSH suppression (<0.1 mIU/L) is inappropriate for Hashimoto's patients unless they have concurrent thyroid cancer requiring suppression. 1 If TSH becomes suppressed on therapy, reduce levothyroxine dose by 12.5-25 mcg. 1

Special Populations

Pregnant women: Maintain TSH in trimester-specific reference ranges with more frequent monitoring (every 4 weeks). 5 Reduce to pre-pregnancy dose immediately postpartum. 5

Pediatric patients: Monitor TSH and free T4 at 2 and 4 weeks after initiation, 2 weeks after dose changes, then every 3-12 months until growth completed. 5 Assess development, growth, and bone maturation regularly. 5

Patients on immunotherapy: Check TSH every 4-6 weeks, as thyroid dysfunction occurs in 5-10% with anti-PD-1/PD-L1 therapy. 1

Long-Term Prognosis

Most Hashimoto's patients require lifelong levothyroxine therapy. 3, 8 The disease is associated with 1.6-fold increased risk of papillary thyroid cancer and 60-fold increased risk of thyroid lymphoma compared to general population, warranting vigilance for nodular changes. 3