Hashimoto Thyroiditis

Excerpt

Hashimoto thyroiditis is an autoimmune disease characterized by destruction of thyroid follicular cells via cell- and antibody-mediated mechanisms. This disease is also known as chronic autoimmune thyroiditis and chronic lymphocytic thyroiditis. Hashimoto thyroiditis is the most common cause of hypothyroidism in developed countries. The pathophysiology of this disease involves the formation of antithyroid antibodies and T cell activation that target thyroid tissue, leading to progressive fibrosis. Together with Graves disease, this condition comes in the category of autoimmune thyroid disorders. This condition was initially described by the Japanese physician Haruto Hashimoto in 1912 as "struma lymphomatosa" after he observed enlarged thyroids with lymphocytic infiltration.

Women are more commonly affected. The female-to-male ratio is at least 7:1 to 10:1. The incidence of Hashimoto thyroiditis increases with age, with most cases occurring between ages 45 and 55. The incidence tends to be higher in countries with lower iodine deficiency prevalence. Hashimoto thyroiditis can occur alone or as part of autoimmune polyglandular syndrome. Some individuals with Graves disease might transform into Hashimoto thyroiditis and vice versa. This could indicate a common pathogenesis for these disorders, but different clinical presentations.