Recurrent Hemithyroiditis：A Case Report

「Abstract.」We report on a girl with recurrent painful thyroiditis which involved the entire right thyroid lobe, but did not spread to the left thyroid lobe. She occasionally developed pain and swelling of the right side of the neck following symptoms of common cold over several years. During these attacks, the right thyroid lobe was enlarged, tender, and very soft, while the left thyroid lobe was not remarkable. Ultrasonic examination revealed that the entire right thyroid lobe was hypoechoic, but the entire left lobe was normal echoic. Serum C-reactive protein, white blood cell count, and erythrocyte sedimentation rate were increased during the attacks. The thyroiditis responded quickly to treatment with prednisolone and/or anti-inflammatory drugs, but the thyroiditis may have subsided spontaneously since the signs and symptoms of thyroiditis had subsided with only antibiotic therapy. After resolution of the thyroiditis, the echogenicity of the right lobe returned to near normal and the inflammatory findings became negative. During the investigation, thyroid function was normal except for when the thyroiditis was first diagnosed at another hospital with a serum TSH level of 0.1 mU/l. Serum thyroglobulin level was increased but returned to normal or decreased during and after attacks of thyroiditis. The mechanism(s) of the recurrent hemithyroiditis remains unknown, but the underlying disease appeared to be chronic thyroiditis since tests for anti-microsomal or anti-thyroid peroxidase antibodies were consistently positive during the course of her illness. The changes in the titers of these antibodies were not clear during and after the attacks of thyroiditis. In addition, the clinical course suggests that the present hemithyroditis can be induced by recurrent upper respiratory infection.