B43-28 No Time to Catch a Breath: Amyopathic Dermatomyositis Presenting as Rapidly Progressive Interstitial Lung Disease

Abstract Introduction Rapidly progressive interstitial lung disease (RP-ILD) is a subset of ILD characterized by acute or subacute deterioration in respiratory status, with progression to respiratory failure occurring within days to weeks in the absence of alternative explanations. This clinical course is distinct from the more gradual progression seen in other forms of ILD, and is associated with high morbidity and mortality with rates up to 66%. RP-ILD most commonly occurs in the context of systemic autoimmune rheumatic diseases, particularly idiopathic inflammatory myopathies (IIM) such as amyopathic dermatomyositis (CADM) and antisynthetase syndrome. Risk factors for myositis-associated RP-ILD include anti-MDA5 antibodies, anti-Ro-52 antibodies, and older age. Diagnosis is based on clinical factors with rapid progression of hypoxemia and elevated acute phase reactants with worsening radiographic ground-glass opacities (GGOs) also observed, though these can mimic the presentation of ARDS. Case Presentation A 34-year-old woman with systemic lupus erythematosus and rheumatoid arthritis presented for dyspnea after finishing a steroid taper for organizing pneumonia with MDA-5 seropositivity. Upon admission she was treated with pulse dose prednisone to achieve immunosuppression given concern for an autoimmune flare, but her condition rapidly declined, requiring intubation and then V-V ECMO for P/F ratio of 80. Her rapid progression of hypoxemia and worsening GGOs suggested RP-ILD, with CADM suspected due to her MDA-5 status. Immunosuppressive therapy was escalated with stress dose methylprednisolone, hydroxychloroquine, cyclophosphamide, tacrolimus, and IVIG all added. Unfortunately, she was unable to be weaned from life support. She was transferred to a transplant center after 41 days on ECMO but ultimately deemed not a transplant candidate. Comfort care was recommended. Discussion ILD is common in patients with IIM, with most patients experiencing a chronic disease course; however up to 9% of patients with IIM develop rapidly progressive ILD. RP-ILD with Anti-MDA5 seropositivity is consistent with CADM and has a poor prognosis. While these patients are at high risk for mortality even when immunosuppression is promptly initiated, a prospective study showed effectiveness of early combined immunosuppression (glucocorticoids, tacrolimus, cyclophosphamide) for MDA-5 IIM. As not all patients will be candidates for lung transplant, medical therapy could be the difference between life and death. Conclusion Rapidly Progressive Interstitial Lung Disease is associated with high morbidity and mortality. Early diagnosis and initiation of treatment can prove critical for preventing rapid decline. This abstract is funded by: None