Alsulami Kawthar, D'Aoust Julie
Rheumatology, King Abdulaziz University Faculty of Medicine, Jeddah, SAU.
Rheumatology, University of Ottawa, Ottawa, CAN.
Cureus. 2024 Oct 24;16(10):e72310. doi: 10.7759/cureus.72310. eCollection 2024 Oct.
Mixed connective tissue disease (MCTD) is an autoimmune disorder characterized by high levels of anti-U1 ribonucleoprotein (RNP) antibodies and overlapping clinical features of autoimmune diseases, such as systemic lupus erythematosus (SLE), systemic sclerosis (SSc), and polymyositis (PM). Anti-Ku antibodies have been associated with overlap syndromes, which can present with symptoms such as Raynaud's phenomenon, arthritis, and myositis. A 19-year-old male athlete presented with myositis, notable for cardiac involvement. Diagnostic testing revealed elevated anti-RNP and anti-Ku antibodies, and a muscle biopsy indicated scleromyositis/overlap myositis. The patient was treated with high-dose corticosteroids, intravenous immunoglobulin (IVIG), rituximab, and mycophenolate mofetil, which led to significant improvement in muscle strength and cardiac function. This case highlights the diagnostic complexity of MCTD when associated with positive anti-Ku antibodies, overlap syndromes, and cardiac involvement. Successful management emphasizes the importance of a tailored, multi-modal therapeutic approach.
混合性结缔组织病（MCTD）是一种自身免疫性疾病，其特征是抗U1核糖核蛋白（RNP）抗体水平升高，以及自身免疫性疾病的重叠临床特征，如系统性红斑狼疮（SLE）、系统性硬化症（SSc）和多发性肌炎（PM）。抗Ku抗体与重叠综合征有关，重叠综合征可表现为雷诺现象、关节炎和肌炎等症状。一名19岁男性运动员出现肌炎，以心脏受累为显著特征。诊断性检查显示抗RNP和抗Ku抗体升高，肌肉活检提示硬化性肌炎/重叠性肌炎。该患者接受了大剂量皮质类固醇、静脉注射免疫球蛋白（IVIG）、利妥昔单抗和霉酚酸酯治疗，这导致肌肉力量和心脏功能有显著改善。该病例突出了MCTD与抗Ku抗体阳性、重叠综合征和心脏受累相关时的诊断复杂性。成功的治疗强调了量身定制的多模式治疗方法的重要性。
