Antithyroid arthritis syndrome: A case report and review of the literature.

A 29-year-old woman was diagnosed with Graves' disease because of her symptoms of thyrotoxicosis. After a 15-day treatment with methimazole, she began to suffer from a repeated fever, rash, and polyarticular migratory arthralgias. The clinical examination on admission showed that her white blood cell count, neutrophil count, and erythrocyte sedimentation rate (ESR) were within normal limits, while the concentration of C-creative protein (CRP) was 26.14 mg/L (ref. 0 - 10) and anti-nuclear immune body (ANA) and anti-neutrophil cytoplasmic antibody (ANCA) were both negative. Upon stopping the drug treatment, the patient's symptoms promptly disappeared. Antithyroid arthritis syndrome is poorly characterized, and the findings from our literature review indicate that this syndrome exhibits serological features that are distinct from those of antithyroid agent-induced vasculitis syndrome. Furthermore, physician's awareness of this syndrome is essential for its diagnosis in clinical practice.