What is Hashimoto's (Hashimoto's thyroiditis)?

From the Guidelines

Hashimoto's thyroiditis should be treated with daily synthetic thyroid hormone replacement, most commonly levothyroxine, to improve morbidity, mortality, and quality of life outcomes. The treatment approach for Hashimoto's thyroiditis typically involves oral T4 monotherapy (levothyroxine sodium) 1. The medication should be taken on an empty stomach, 30-60 minutes before breakfast or 3-4 hours after the last meal of the day, avoiding calcium, iron supplements, and certain foods that can interfere with absorption.

Key Considerations

• Regular blood tests (every 6-8 weeks initially, then every 6-12 months once stabilized) are necessary to monitor thyroid stimulating hormone (TSH) levels and adjust medication dosage accordingly 1.
• Patients should maintain a balanced diet, consider limiting goitrogenic foods (like raw cruciferous vegetables) if they cause discomfort, and address selenium and vitamin D deficiencies if present.
• Hashimoto's often progresses slowly, with the immune system gradually destroying thyroid tissue, which explains why many patients require increasing medication doses over time as their natural thyroid function diminishes.

Screening and Diagnosis

• The serum TSH test is the primary screening test for thyroid dysfunction, and multiple tests should be done over a 3- to 6-month interval to confirm or rule out abnormal findings 1.
• Follow-up testing of serum T4 levels in persons with persistently abnormal TSH levels can differentiate between subclinical (normal T4 levels) and “overt” (abnormal T4 levels) thyroid dysfunction.

Treatment Outcomes

• Although detection and treatment of abnormal TSH levels (with or without abnormal T4 levels) in asymptomatic persons is common practice, evidence that this clinical approach improves important health outcomes is lacking 1.
• Long-term randomized, blinded, controlled trials of screening for thyroid dysfunction would provide the most direct evidence on any potential benefits of this widespread practice.

From the Research

Hashimoto's Disease Overview

• Hashimoto's disease is a common autoimmune disorder that affects women 7-10 times more often than men, leading to an imbalance in self-tolerance mechanisms and destruction of thyrocytes 2.
• The presence of thyroid peroxidase antibodies (TPOAbs) is associated with a 2 to 4-fold increase in the risk of recurrent miscarriages and preterm birth in pregnant women 2.
• The clinical presentation of Hashimoto's disease includes thyrotoxicosis, euthyroidism, and hypothyroidism, with management varying depending on the stage of the disease 2.

Diagnosis and Treatment

• The diagnosis of subclinical hypothyroidism should be confirmed by repeat thyroid function tests ideally obtained at least 2 months later, as 62% of elevated TSH levels may revert to normal spontaneously 3.
• Treatment is not necessary unless the TSH exceeds 7.0-10 mIU/L, and treatment does not improve symptoms or cognitive function if the TSH is less than 10 mIU/L 3.
• Levothyroxine (LT4) is used as a standard-of-care treatment in patients with hypothyroidism, with the dose based on the degree of preserved thyroid functionality and lean body mass, usually ranging from 1.4 to 1.8 mcg/kg/day 2.
• In some cases, switching to levothyroxine sodium oral solution may be beneficial, especially in patients with malabsorption issues or gastrointestinal disorders 4.

Treatment Considerations

• TSH goals are age-dependent, with a 97.5 percentile (upper limit of normal) of 3.6 mIU/L for patients under age 40, and 7.5 mIU/L for patients over age 80 3.
• Combined treatment with levothyroxine and liothyronine may be preferred in some hypothyroid patients who are dissatisfied with treatment, especially those with a polymorphism in type 2 deiodinase 3.
• Overzealous treatment of symptomatic patients with subclinical hypothyroidism may contribute to dissatisfaction among hypothyroidism patients, and treatment may be harmful in elderly patients with subclinical hypothyroidism 3.