Myositis-Associated Interstitial Lung Disease Presenting as Acute Respiratory Distress Syndrome: A Retrospective Observational Study

Background/Objectives: Myositis-associated interstitial lung disease (ILD) can occasionally present as acute respiratory distress syndrome (ARDS); however, clinical data on this presentation remain limited. This study aimed to describe the clinical characteristics and outcomes of patients with myositis-associated ILD presenting as ARDS. Methods: We conducted a single-center retrospective observational study of patients with myositis-associated ILD who were admitted to the intensive care unit (ICU) for acute hypoxemic respiratory failure. Results: Ten patients positive for myositis-specific antibodies met the new global ARDS definition. The median age was 62 years, and eight patients were male. Antibody profiles included anti-MDA-5 (n = 5), anti-synthetase antibodies (Jo-1 [n = 1], PL-7 [n = 2], EJ [n = 4]), and NXP-2 (n = 1). Fever and cutaneous manifestations were the most common extrapulmonary features. Chest computed tomography demonstrated diffuse alveolar damage patterns in six patients and organizing pneumonia patterns in four. At ICU admission, four patients required mechanical ventilation and six received high-flow nasal cannula, of whom four subsequently progressed to mechanical ventilation. Extracorporeal membrane oxygenation was implemented in three patients. All patients received high-dose corticosteroids, six underwent steroid pulse therapy, and four additionally received immunosuppressive agents. Six patients died during hospitalization. Conclusions: Myositis-associated ILD may present as ARDS and should be considered in patients with ARDS of unclear etiology. Careful physical examination and autoantibody testing may assist in recognizing this condition in the critical care setting.