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

From the Guidelines

Hashimoto's thyroiditis is an autoimmune disorder where the immune system attacks the thyroid gland, leading to chronic inflammation and eventual hypothyroidism, primarily affecting women between 40-60 years old with a genetic component, as noted in studies such as 1 and 1.

Key Points

• The condition is characterized by symptoms including fatigue, weight gain, cold intolerance, dry skin, constipation, depression, and sometimes a visible goiter (enlarged thyroid) as discussed in 1.
• Diagnosis typically involves blood tests measuring thyroid hormones (TSH, T4, T3) and thyroid antibodies (anti-TPO and anti-thyroglobulin) as outlined in 1.
• Treatment centers on synthetic thyroid hormone replacement, usually levothyroxine, with typical starting doses of 1.6 mcg/kg body weight daily, taken on an empty stomach 30-60 minutes before breakfast, as recommended in 1.
• Regular monitoring with blood tests every 6-12 months is necessary to adjust dosage as needed, and patients should maintain consistent timing with medication, avoiding certain substances and understanding that treatment is typically lifelong, as suggested by 1 and 1.
• While some patients explore dietary changes, these approaches should complement rather than replace conventional treatment, as indicated in 1.

Risk Factors and Screening

• Risk factors for an elevated TSH level include female sex, advancing age, white race, type 1 diabetes, Down syndrome, family history of thyroid disease, goiter, previous hyperthyroidism, and external-beam radiation in the head and neck area, as identified in 1 and 1.
• The serum TSH test is the primary screening test for thyroid dysfunction, with multiple tests done over a 3- to 6-month interval to confirm or rule out abnormal findings, as discussed in 1 and 1.
• The optimal screening interval for thyroid dysfunction is unknown, but follow-up testing of serum T4 levels in persons with persistently abnormal TSH levels can differentiate between subclinical and overt thyroid dysfunction, as noted in 1 and 1.

From the FDA Drug Label

As pituitary thyroid-stimulating hormone (TSH) suppressants, in the treatment or prevention of various types of euthyroid goiters, including thyroid nodules, subacute or chronic lymphocytic thyroiditis (Hashimoto's) and multinodular goiter Hashimoto's thyroiditis is chronic lymphocytic thyroiditis.

• It is a type of hypothyroidism of any etiology.
• Hashimoto's is mentioned as a condition for which thyroid hormone drugs, such as liothyronine, can be used as replacement or supplemental therapy 2.

From the Research

Definition and Causes of Hashimoto's Thyroiditis

• Hashimoto's thyroiditis (HT) is a common autoimmune disorder that affects women 7-10 times more often than men, caused by genetic susceptibility, environmental factors, and microbiome composition, leading to an imbalance in self-tolerance mechanisms 3.
• The disease is characterized by thyroid infiltration by lymphocytes, potentiated by antibody-mediated autoimmune response through the antibodies against thyroid peroxidase (TPOAbs) 3.
• HT is associated with a 2 to 4-fold increase in the risk of recurrent miscarriages and preterm birth in pregnant women 3.

Clinical Presentation and Management

• The clinical presentation of HT includes thyrotoxicosis, euthyroidism, and hypothyroidism, depending on the extent of thyroid damage and hormone production 3.
• The management of HT depends on its clinical manifestations, including lifelong levothyroxine substitution in most cases 4.
• The dose of levothyroxine (LT4) used for treatment is based on the degree of preserved thyroid functionality and lean body mass, and usually ranges from 1.4 to 1.8 mcg/kg/day 3.
• There is insufficient evidence to recommend for or against therapy with triiodothyronine (T3), apart from in pregnancy when only levothyroxine is indicated 3.

Associated Risks and Complications

• HT is associated with a 1.6 times higher risk of papillary thyroid cancer and 60 times higher risk of thyroid lymphoma than in the general population 3.
• Patients with HT may also experience various symptoms, including neuropsychological/psychiatric deficits, decreased left ventricular performance, disorders of the gut, fibromyalgia, and reproductive health issues, even when thyroid parameters are within the normal range 5.
• Co-morbidities, such as other organ-specific autoimmune diseases, psychiatric diseases, and lack of vitamin and trace elements, may contribute to poor response to therapy despite normal TSH levels 6.

Diagnostic and Therapeutic Considerations

• Diagnosis of HT requires a detailed medical history, sonography, and blood analysis of thyroid function and thyroid antibodies 6.
• Surgical treatment may be indicated in patients with HT who have thyromegaly with compression symptoms, nodular form of HT with dominant thyroid nodules, suspicion for neoplasm, or an unsightly neck appearance due to a large goiter 7.
• Argon plasma resection (APR) is a new, safe, and promising technique of thyroid resection, particularly appropriate for patients with HT 7.