Low incidence of painless thyroiditis in the Philadelphia area.

Publications from the midwestern region of the United States have demonstrated an incidence of 14-23% of painless thyroiditis in hyperthyroid individuals. This possibly could represent a local phenomenon, and perhaps is not typical for other areas of the country. The 24 hour radioactive iodine uptakes in 152 consecutive hyperthyroid individuals in the Philadelphia area were evaluated. No patient in the series, with clinical and biochemical evidence of hyperthyroidism, had painless thyroiditis. It is concluded that the incidence of painless thyroiditis is markedly lower in the Philadelphia area than in the Midwest regions of the United States.