A case of encephalitis in a juvenile rheumatoid arthritis patient treated with etanercept

Tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$) is a major proinflammatory cytokine involved in the pathophysiology of juvenile rheumatoid arthritis. Etanercept is an effective inhibitor of $TNF-{\alpha}$ and has shown a beneficial effect in patients with JRA. However, the most important cause of concern related to etanercept administration is infection. We report a case of encephalitis in a JRA patient receiving long-term treatment with etanercept. The patient was a 4-year-old boy with refractory JRA, and he received etanercept subcutaneously at a dose of $0.4\;mg\;kg^{-1}\;day^{-1}$ twice a week for 14 months, along with non-steroidal anti-inflammatory drugs, methotrexate, oral steroids, and sulfasalazine. The patient presented with sudden fever, headache, vomiting, a generalized tonic seizure, and changes in mental status. We suspected a central nervous system infection, and simultaneously administered antibiotics, an antiviral agent, and steroids. After 2 days of hospitalization, his mental function returned to normal, and he showed no further seizure-like movements. Brain magnetic resonance imaging scan of the patient showed a multifocal cortical lesion on both sides of the temporoparietooccipital lobe, which indicated encephalitis. Although we were unable to identify the causative organism of encephalitis, we think that the encephalitis may be attributed to infection, and the use of etanercept may have increased the risk of severe infection. Therefore, etanercept was discontinued and the patient recovered shortly after. To the best of our knowledge, this is the first case of encephalitis in a juvenile rheumatoid arthritis patient treated with etanercept.

소아기 류마티스모양 관절염 환자에서 etanercept 사용 후 발생한 뇌염 1예

$TNF-{\alpha}$ 는 소아기 류마티스모양 관절염의 병태생리학에 관여하는 주요 cytokine 이다. Etanercept 는 $TNF-{\alpha}$ 억제제 중 하나로 소아기 류마티스모양 관절염에 효과적인 약물로 각광받고 있다. Etanercept의 주요 부작용은 면역력 저하에 의한 감염으로, 대게 중등도의 상기도 감염이 대부분으로 알려져 있으나, 최근 중증의 감염도 보고되고 있다. 저자들은 소아기 류마티스모양 관절염 환자가 etanercept를 14개월간 투약 후 발생한 뇌염 1예를 경험하였기에 보고하는 바이다.