RT Journal Article SR Electronic T1 Polymyositis after propylthiouracil treatment for hyperthyroidism. JF Annals of the Rheumatic Diseases JO Ann Rheum Dis FD BMJ Publishing Group Ltd and European League Against Rheumatism SP 340 OP 343 DO 10.1136/ard.47.4.340 VO 47 IS 4 A1 Shergy, W J A1 Caldwell, D S YR 1988 UL http://ard.bmj.com/content/47/4/340.abstract AB An additional disorder in the spectrum of thyroid related muscle disease is presented. Hypothyroid and hyperthyroid disease are both associated with a variety of muscle abnormalities, from myalgias to myopathy. Polymyositis, however, has never been reported immediately after treatment for active hyperthyroidism. A patient is presented with typical hyperthyroidism, who developed a severe proximal muscle weakness and a raised creatine phosphokinase after treatment for hyperthyroidism with propylthiouracil (100 mg orally, three times a day). Electromyography, muscle biopsy, and the course of the patient's illness were consistent with polymyositis. Whether this represents a cause-effect association or a chance occurrence is unknown. Physician awareness of the occurrence of a variety of muscle disorders including polymyositis in thyroid disease is emphasised. A brief discussion of thyroid myopathy, thionamide drug reactions, and polymyositis is included.