Asymptomatic atrophic thyroiditis.

Asymptomatic atrophic thyroiditis (AAT), one of the three variants of autoimmune thyroiditis, is characterized by the presence of serum antithyroid antibodies in good correlation with thyroid lymphoplasmocytic infiltrations. AAT affects 5-15% of the general population and is especially prevalent in elderly women. Patients with AAT have no goitre and are clinically euthyroid. While circulating thyroid hormones are always in the normal range, peak TSH and TRH and basal TSH values are increased in two thirds of the cases. There is a familial aggregation of AAT and a frequent association with other autoimmune diseases. Development of overt hypothyroidism in AAT patients is not rare. Preventive thyroid replacement therapy is indicated in patients with elevated basal TSH levels.