Children's Mercy Hospital, Kansas City, MO, USA.
School of Medicine, University of Missouri-Kansas City, Kansas City, MO, USA.
Pediatr Rheumatol Online J. 2024 Sep 17;22(1):86. doi: 10.1186/s12969-024-01021-y.
Juvenile Dermatomyositis (JDM) is a rare disorder with subtypes associated with different myositis-specific antibodies (MSAs) including anti-MDA5. Hepatic involvement in JDM is rare and has not previously been documented in anti-MDA5 JDM. There is a lack of formal research on treatment protocols for anti-MDA5 JDM, though tofacitinib is a highly regarded emerging therapy.
A previously healthy 14-month-old Hispanic female presented to a pediatric rheumatology clinic with eight months of worsening rash, weakness, periorbital edema, intermittent fevers, and weight loss. Her physical exam was notable for fever, thinning of hair, heliotrope rash, periorbital edema, violaceous macules on her bilateral elbows, forearms, arms, and knees, arthritis, Gottron's sign, and hepatomegaly. The patient was admitted, and symptoms progressed to include hypoxemia. Subsequent workup was notable for ground glass opacities of bilateral lung fields on chest CT, myositis visualized on MRI and confirmed with muscle biopsy, and liver biopsy showing nonspecific signs of liver injury. After a thorough infectious disease workup to rule out concomitant infection, the patient was started on high-dose steroids and induction with cyclophosphamide. She responded well with disease remission maintained with tofacitinib in the outpatient setting.
Our patient is notable due to her young age at presentation, histopathologically confirmed liver injury, and response to treatment. The case adds to the growing body of literature supporting tofacitinib for anti-MDA5 JDM in the pediatric population. Future research can better standardize effective treatment protocols and define the mechanism of liver involvement. For patients with nonspecific liver injury, muscular, and cutaneous disease, anti-MDA5 JDM should be considered in the differential diagnosis with treatment options including tofacitinib for confirmed cases.
幼年皮肌炎（JDM）是一种罕见疾病，其亚型与不同的肌炎特异性抗体（MSA）相关，包括抗 MDA5。JDM 中的肝脏受累很少见，以前也没有在抗 MDA5 JDM 中记录过。虽然托法替尼是一种备受推崇的新兴疗法，但针对抗 MDA5 JDM 的治疗方案缺乏正式研究。
一名 14 个月大的西班牙裔健康女婴因皮疹、乏力、眶周水肿、间歇性发热和体重减轻恶化 8 个月，到儿科风湿病诊所就诊。她的体格检查发现有发热、毛发稀疏、向阳疹、眶周水肿、双侧肘部、前臂、手臂和膝盖上的紫红色斑疹、关节炎、Gottron 征和肝肿大。患者被收入院，症状进展为低氧血症。随后的检查显示胸部 CT 上双侧肺野磨玻璃影、MRI 显示肌炎并经肌肉活检证实、肝脏活检显示非特异性肝损伤。在彻底进行传染病检查以排除合并感染后，患者开始接受大剂量类固醇和环磷酰胺诱导治疗。她对治疗反应良好，疾病缓解后在门诊接受托法替尼维持治疗。
我们的患者因以下原因而引人注目：发病年龄小、组织病理学证实的肝脏损伤和对治疗的反应。该病例增加了越来越多的文献支持托法替尼在儿科人群中用于抗 MDA5 JDM。未来的研究可以更好地规范有效的治疗方案，并确定肝脏受累的机制。对于有非特异性肝脏损伤、肌肉和皮肤疾病的患者，在鉴别诊断中应考虑抗 MDA5 JDM，治疗选择包括对确诊病例使用托法替尼。
