Mehair Alaa S, Harjacek Miroslav
Pediatric Medicine, Tawam Hospital, Abu Dhabi, ARE.
Cureus. 2024 Dec 5;16(12):e75137. doi: 10.7759/cureus.75137. eCollection 2024 Dec.
There are several types of inflammatory myopathies, including juvenile dermatomyositis (JDM), which is characterized by muscle inflammation that can eventually lead to weakness. A devastating complication of JDM is macrophage activation syndrome (MAS), although reports of MAS in JDM patients are limited. Additionally, cases of JDM associated with positive anti-MDA5 are rare and represent a fatal subtype of inflammatory myopathies, with a significant risk of lung impairment. This case report discusses a six-year-old girl presenting with proximal muscle weakness and cutaneous changes, including heliotrope rash and Gottron's papules, who was diagnosed with JDM. Muscle involvement was confirmed through MRI of the thigh muscles. Laboratory findings revealed elevated aldolase, hepatitis, high lactate dehydrogenase, and hyperferritinemia, leading to a diagnosis of JDM complicated by MAS. Pulse steroid therapy combined with cyclosporine was initiated, and she showed significant improvement initially. However, she later tested positive for anti-MDA5 antibodies, a marker associated with a poor prognosis. Highlighting MAS as a potential complication in JDM cases with positive anti-MDA5 antibodies can help physicians recognize this outcome and consider it in the differential diagnosis.
炎症性肌病有多种类型，包括幼年皮肌炎（JDM），其特征为肌肉炎症，最终可导致肌无力。巨噬细胞活化综合征（MAS）是JDM的一种严重并发症，不过关于JDM患者中MAS的报道有限。此外，与抗MDA5抗体阳性相关的JDM病例罕见，代表炎症性肌病的一种致命亚型，有显著的肺损伤风险。本病例报告讨论了一名6岁女童，出现近端肌无力和皮肤改变，包括向阳疹和Gottron丘疹，被诊断为JDM。通过大腿肌肉的MRI证实了肌肉受累。实验室检查结果显示醛缩酶升高、肝炎、乳酸脱氢酶升高和高铁蛋白血症，诊断为JDM并发MAS。开始采用脉冲类固醇疗法联合环孢素治疗，她最初显示出显著改善。然而，她后来抗MDA5抗体检测呈阳性，这是一种与预后不良相关的标志物。强调MAS作为抗MDA5抗体阳性的JDM病例的潜在并发症，有助于医生认识到这一结果并在鉴别诊断中加以考虑。
