胸骨正中切開拡大胸腺摘除術を控え，クリーゼ予防としてジルコプランを導入した球麻痺を伴う全身型重症筋無力症の一例

Myasthenia Gravis Treated with Zilucoplan Prior to Extended Transsternal Thymectomy for the Prevention of Myasthenic Crisis: A Case Report

誤嚥性肺炎を契機に胸腺腫合併重症筋無力症と診断された50歳女性。少量の副腎皮質ステロイド薬と経静脈的免疫グロブリン療法が行われたが嚥下障害が残存した。胸骨正中切開拡大胸腺摘除術を行ううえでクリーゼ予防のため免疫治療の強化が必要で，効果発現の早さや併用薬の観点からジルコプランを選択しすみやかに嚥下障害は改善し，術後の良好な転帰を得た。本例はジルコプランを周術期のクリーゼ予防に使用した重要な報告である。

Abstract

A 50year-old female was diagnosed with myasthenia gravis (MG) following aspiration pneumonia. Despite treatment with prednisolone (5mg/day) and intravenous immunoglobulin (IVIg), the bulbar palsy persisted. Additionally, chest CT revealed findings suggestive of invasive thymoma or thymic carcinoma, leading to a planned thymectomy with median sternotomy. This case presents a high-risk of myasthenic crisis due to thymoma-associated MG, persistent bulbar palsy, and the need for highly invasive surgery. Therefore, enhanced immunotherapy was required to prevent this crisis, and zilucoplan was chosen because of its rapid onset of action and compatibility with IVIg. Following the initiation of zilucoplan, there was prompt improvement in the symptoms of MG. Effective preoperative control of MG led to a good clinical course, with no significant postoperative myasthenic crisis or exacerbation of symptoms. This is the first report on the use of zilucoplan for the prevention of perioperative myasthenic crisis.

(Received April 14, 2025; Accepted June 3, 2025, Published August 1, 2025)