Hashimoto’s Thyroiditis

Epidemiology

This autoimmune disease of the thyroid gland is the most common form of chronic thyroiditis. The disease is also known as “chronic lymphocytic thyroiditis” and “lymphadenoid goiter.” The incidence in females is four to five times more common than in males. The disease is most common in the fifth and sixth decades of life and increases in incidence with increasing age. There is a strong association between Hashimoto’s disease and primary thyroid lymphoma. The majority of patients with thyroid lymphoma have coexistent Hashimoto’s thyroiditis, and a small proportion of patients with Hashimoto’s thyroiditis develop primary thyroid lymphoma. Other disorders that may be associated with Hashimoto’s disease include Sjögren’s syndrome, chronic active hepatitis, systemic lupus erythematosus, rheumatoid arthritis, adrenal insufficiency (Schmidt’s syndrome), diabetes mellitus, opathic thrombocytopenia, pernicious anemia, and Graves’ disease.

Clinical Findings

There are two clinical forms of the disease. In one type (“atrophic form”), the gland is normal or reduced in size and the patients are hypothyroid. This may be the same syndrome as idiopathic myxedema.

The second form is characterized by variable degrees of thyroid enlargement and patients complain of signs and symptoms associated with a goiter. The gland is symmetrically enlarged and firm on palpation. Patients are typically hypothyroid and may have a family history of Graves’ or Hashimoto’s disease.