B43-20 A Refractory Case of Anti-MDA5 Dermatomyositis Rapidly Progressive Interstitial Lung Disease Successfully Treated With Immunosuppression, Veno-venous Extracorporeal Membranous Oxygenation (vvECMO), and Bilateral Lung Transplant

Abstract Introduction Anti-melanoma differentiation-associated protein 5 antibody-positive dermatomyositis (MDA5-DM) is a distinct subtype of dermatomyositis characterized by rashes (Grotton’s papules, heliotrope rash), amyopathic/hypomyopathic muscle involvement, and rapidly progressive interstitial lung disease (RP-ILD) that can result in fulminant ILD within 1 month of symptom onset1,2. The presence of radiographic nonspecific interstitial pneumonia- organizing pneumonia (NSIP-OP) pattern may be predictive of RP-ILD with poor prognosis3. Controversy exists whether immunosuppression should be done step-wise vs upfront combination therapy but the Japanese literature suggests improved outcomes with upfront combination therapy4–6. Here we present a case of anti-MDA5 RP-ILD refractory to upfront combination immunosuppression successfully treated with veno-venous extracorporal membrane oxygenation (vvECMO) followed by bilateral lung transplantation. Case Presentation A 34-year-old male with a family history of idiopathic pulmonary fibrosis presented with one week of fevers, months of progressive dyspnea on exertion, and arthralgias with consolidations on CT chest and minimal oxygen requirement. He completed an outpatient course of azithromycin without improvement. He was noted to have a new heliotrope rash and underwent skin biopsy for dermatomyositis confirmation; a serum myositis panel was also sent. On hospital day 3, he developed profound hypoxia requiring high flow nasal cannula with worsening consolidations on CT in an NSIP-OP pattern (Figure 1). Antibiotics were broadened and patient underwent intubation with bronchoscopy to rule out infection prior to immunosuppression. After infectious studies returned negative, he was started on pulse dose methylprednisolone, cyclophosphamide, IVIG, and rituximab. His ventilator was managed using lung protective ventilation strategies. His anti-MDA5 receptor antibody returned positive on hospital day 10. Despite these measures, his respiratory failure worsened with new pneumomediastinum. On hospital day 15, he was cannulated for vvECMO and underwent bilateral lung transplantation on hospital day 47. He was decannulated but developed a left pulmonary vein thrombosis with necrosed lung requiring left allograft pneumonectomy. Ultimately, he survived and was discharged home on hospital day 125. Discussion Anti-MDA5 RP-ILD refractory to immunosuppression carries high mortality with limited treatment options. Risk factors include age, male sex, lymphopenia, elevated inflammatory markers, hyperferritanemia, and radiographic NSIP-OP pattern on CT3,7. The presence of pneumomediastinum is indicative of severe disease7. Upfront combination immunosuppressive therapy may result in improved outcomes, but further clinical investigation is required. Conclusion Anti-MDA5 RP-ILD is a life-threatening condition that is potentially curable with aggressive immunosuppression and bilateral lung transplant in refractory cases. Early identification is vital for referral to an ECMO and transplant center for definitive management. This abstract is funded by: N/A