Hashimotos

Hashimoto's thyroiditis, commonly called Hashimoto disease, is a chronic autoimmune disorder in which the immune system attacks the thyroid gland, often leading to gradual loss of thyroid function and hypothyroidism. It is named after Hakaru Hashimoto, who first described the condition in 1912. The disease is the most common cause of hypothyroidism in areas with adequate iodine and is more frequent in women, typically presenting in middle age though it can occur at any age.

Pathophysiology involves immune-mediated destruction of thyroid tissue with infiltration by lymphocytes and the formation of germinal centers. The body also produces autoantibodies, most commonly against thyroid peroxidase (TPO) and thyroglobulin. Some individuals may experience a temporary hyperthyroid phase, but progression to reduced thyroid hormone production is common.

Clinical features can be insidious. Patients may report fatigue, weight gain, cold intolerance, constipation, dry skin, hair loss, and menstrual changes. A goiter may be present or small. Diagnosis is supported by elevated thyroid-stimulating hormone (TSH) with low free thyroxine (T4) and positive thyroid antibodies, particularly anti-TPO. Ultrasound can show a heterogeneous, often hypoechoic thyroid.

Treatment consists of lifelong thyroid hormone replacement, usually with levothyroxine, titrated to achieve a normal TSH level. Regular monitoring is recommended, especially during pregnancy and in older individuals. Hashimoto's may be associated with other autoimmune diseases such as type 1 diabetes or celiac disease. With appropriate treatment, most people achieve good symptom control and normal metabolic function.