臨床的筋萎縮性皮膚筋炎を合併した急速進行性間質性肺疾患を有する日系アメリカ人女性

A Japanese-American female with rapidly progressive interstitial lung disease associated with clinically amyopathic dermatomyositis.

• Toshinori Takada
• Katsuaki Asakawa
• Roberto Barrios

抄録

臨床的筋炎性皮膚筋炎（CADM）患者は、急速に進行する間質性肺疾患（ILD）を発症するリスクがある。CADM-ILDは抗MDA-5抗体と関連している。しかし、米国では日本に比べてCADM患者の抗MDA-5抗体保有率は低い。また，米国では日本に比べてCADM患者は急速に進行するILDを合併することが少ない．症例は42歳の日系アメリカ人女性で，手と顔面に関節痛を伴う発疹を3ヶ月間認めた．ルーパス検査で陰性であったため，プライマリーケア医とリウマチ専門医によりステロイド，ヒドロキシクロロキン，メトトレキサートによる治療が行われた．治療中、患者は肺炎による息切れを自覚するようになり、CTスキャンで明らかになった。最終的にILDを伴うCADMによる急性呼吸不全と診断された。二重肺移植を行い，複数の免疫抑制剤による治療と血漿交換を繰り返したが，移植後15日で死亡した．彼女の臨床経過は日本人のCADM-ILD患者と同様である。海外では、プライマリーケア医、リウマチ専門医、皮膚科医、肺専門医などは、日本に比べてこの疾患になじみが薄いかもしれない。CADM-ILDは進行が早く、命に関わることもあるため、日系人患者を診る際には、この疾患を知っておくことで、早期に治療を行うことが必要である。

Patients with clinically amyopathic dermatomyositis (CADM) have a risk of developing rapidly progressive interstitial lung disease (ILD). CADM-ILD is associated with the anti-MDA-5 antibody. In the USA, however, patients with CADM have these antibodies less frequently than those in Japan. In addition, those with this disorder are less often complicated with rapidly progressive ILD than those in Japan. We present a case of a 42-year-old Japanese-American female with a 3-month history of a rash on her hands and face with joint pain. Based on the negative results from lupus tests, her primary care provider and a rheumatologist treated her with steroids, hydroxychloroquine, and methotrexate. During treatment, the patient started noticing shortness of breath because of pneumonia, which was revealed by a CT scan. The woman was finally diagnosed with acute respiratory failure due to CADM with ILD. She underwent a double lung transplant as well as treatment with multiple immunosuppressive agents and repeated plasma exchange but died 15 days after transplantation. Her clinical course is similar to that of Japanese patients with CADM-ILD. Outside Japan, primary care providers, rheumatologists, and dermatologists, as well as pulmonary physicians, may be less familiar with this disorder than those in Japan. Since CADM-ILD progresses very quickly and could be fatal, these doctors should be aware of this disease to treat such patients as soon as possible, particularly when seeing a patient of Japanese descent.