Puthumana Rose M, Koch Abigail L, Schettino Christopher, Vehar Susan J
Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, USA.
Division of Pulmonary, Critical Care and Sleep Medicine, University of Miami Miller School of Medicine, Miami, FL, USA.
Respir Med Case Rep. 2024 Jun 18;51:102072. doi: 10.1016/j.rmcr.2024.102072. eCollection 2024.
Anti-melanoma differentiation-associated gene 5-positive (anti-MDA5) dermatomyositis (DM) is a rare autoimmune disease associated with rapidly-progressive interstitial lung disease (RP-ILD.) The reported morbidity and 6-month mortality remains high from 33 to 66 % with RP-ILD most often developing within three months of diagnosis. Most cases require aggressive immunosuppression with combination therapy. Asymptomatic or slowly progressive cases of anti-MDA5 ILD are not well described in the literature. We report three cases of Latino patients with asymptomatic or slowly progressive anti-MDA5 ILD..
CASE 1: A 54-year-old woman from Honduras with known diagnosis of anti-MDA5 dermatomyositis presented for ILD. She denied respiratory symptoms. Computed tomography (CT) chest showed multifocal patchy areas of scattered groundglass opacities throughout all lobes of the lungs, predominately in a subpleural distribution within the lower lobes. Pulmonary function testing (PFTs) showed mild-to-moderate restriction. She was treated with mycophenolate mofetil monotherapy for her skin manifestations. At 18 months follow-up, she denied respiratory symptoms, and PFTs were normal.
CASE 2: An 80-year-old man from Cuba was seen in pulmonary clinic to establish care. He was diagnosed with pulmonary fibrosis 11 years earlier with positive anti-MDA5. He denied respiratory symptoms. PFTs showed moderate obstruction and mild to moderate restriction. CT chest showed reduced lung volumes and findings compatible with usual interstitial pneumonia. He was started on nintedanib. Fifteen months following the initial visit, his PFTs remained stable. Follow-up CT chest showed stable pulmonary fibrosis. At all subsequent visits, he reported mild to moderate, slowly progressive dyspnea on exertion and was maintained on nintedanib. Thirteen years after his initial ILD diagnosis, he was diagnosed with pancreatic adenocarcinoma.
CASE 3: A 70-year-old woman from Peru presented to pulmonary clinic with cough for two months. She also reported pain in several metacarpophalangeal joints. She denied dyspnea. Rheumatologic serologies revealed positive anti-MDA5. PFTs were normal. Her cough was treated with cough suppressants and resolved. At a subsequent visit 8 months after presentation, she denied respiratory symptoms, and her joint pain remained mild. Given her lack of respiratory symptoms and normal PFTs, she was not initiated on ILD-specific treatment.
While anti-MDA5 ILD is certainly associated with RP-ILD, clinicians should maintain awareness that there may be cases of asymptomatic or slowly progressive ILD as well.
抗黑色素瘤分化相关基因5阳性（抗MDA5）皮肌炎（DM）是一种罕见的自身免疫性疾病，与快速进展性间质性肺病（RP-ILD）相关。据报道，RP-ILD的发病率和6个月死亡率仍然很高，为33%至66%，且RP-ILD最常发生在诊断后的三个月内。大多数病例需要联合使用积极的免疫抑制疗法。无症状或缓慢进展的抗MDA5间质性肺病病例在文献中描述较少。我们报告了三例拉丁裔无症状或缓慢进展的抗MDA5间质性肺病患者。
病例1：一名来自洪都拉斯的54岁女性，已知患有抗MDA5皮肌炎，因间质性肺病前来就诊。她否认有呼吸道症状。胸部计算机断层扫描（CT）显示，肺部所有叶均有多发散在的斑片状磨玻璃影，主要分布在下叶的胸膜下区域。肺功能测试（PFTs）显示轻度至中度受限。她因皮肤表现接受霉酚酸酯单药治疗。在18个月的随访中，她否认有呼吸道症状，且肺功能测试结果正常。
病例2：一名来自古巴的80岁男性在肺部诊所就诊以建立治疗方案。他11年前被诊断为肺纤维化，抗MDA5阳性。他否认有呼吸道症状。肺功能测试显示中度阻塞和轻度至中度受限。胸部CT显示肺容积减小，结果符合普通间质性肺炎。他开始使用尼达尼布治疗。初次就诊15个月后，他的肺功能测试结果保持稳定。随访胸部CT显示肺纤维化稳定。在所有后续就诊中，他报告有轻度至中度、缓慢进展的劳力性呼吸困难，并继续使用尼达尼布治疗。在他最初被诊断为间质性肺病13年后，他被诊断出患有胰腺腺癌。
病例3：一名来自秘鲁的70岁女性因咳嗽两个月就诊于肺部诊所。她还报告了几个掌指关节疼痛。她否认有呼吸困难。风湿血清学检查显示抗MDA5阳性。肺功能测试结果正常。她的咳嗽用止咳药治疗后缓解。在就诊后8个月的一次后续就诊中，她否认有呼吸道症状，且关节疼痛仍较轻。鉴于她没有呼吸道症状且肺功能测试结果正常，未对她启动间质性肺病特异性治疗。
虽然抗MDA5间质性肺病肯定与RP-ILD相关，但临床医生应意识到也可能存在无症状或缓慢进展的间质性肺病病例。
