Abstract Introduction Amyopathic dermatomyositis is a rare subset of dermatomyositis that presents a significant diagnostic challenge due to minimal/absent muscle involvement. In its most severe forms, it may present as rapidly progressive interstitial lung disease (RP-ILD) with positive anti-MDA5 antibody, associated with a high six-month mortality rate of 63-75%. We report the case of a 51-year-old woman who presented with dyspnea and rash initially attributed to bilateral pulmonary emboli and possible systemic lupus erythematosus (SLE). She was subsequently diagnosed with anti-MDA5 amyopathic dermatomyositis and ultimately required extracorporeal membrane oxygenation (ECMO) support for RP-ILD. Her disease progressed despite maximal supportive therapy and she died of respiratory failure. Case report A 51-year-old patient with oral contraceptive (OCP) use presented with acute hypoxemic respiratory failure and a discoid rash on the forehead and cheeks. Chest CT pulmonary angiography revealed bilateral pulmonary emboli and bilateral peripheral infiltrates. Initial serologies were positive for lupus anticoagulant antibody and negative for ANA, dsDNA, ANCA. The patient was discharged on apixaban, with a recommendation to discontinue OCPs. A week later, the patient returned with increased oxygen requirements and worsening interstitial opacities. She was transitioned to heparin/warfarin and admitted for empiric treatment of community acquired pneumonia. Their course acutely worsened, necessitating transfer to the ICU for mechanical ventilation. Given refractory hypoxemia despite ARDS treatment and inhaled epoprostenol, veno-venous ECMO was initiated. Examination revealed hyperkeratotic and erythematous scaly papules on the dorsum of her hands. Myositis panel was positive for anti-MDA5 antibody. Bronchoalveolar lavage was incidentally positive for Pneumocystis, but otherwise negative for infectious pathogens. Surgical lung biopsy revealed extensive organizing diffuse alveolar damage and patchy hyaline membranes, all attributed to amyopathic dermatomyositis. Due to progressively worsening respiratory failure despite treatment with high dose steroids and IVIG, tacrolimus and cyclophosphamide were added as salvage treatment. Despite this, vasopressor requirements and hypercarbia worsened. Given the poor prognosis and progressive respiratory deterioration, the decision was made to transition to comfort care. Discussion Anti-MDA amyopathic dermatomyositis is a rare but critical diagnosis due to its strong association with RP-ILD and high mortality. Early recognition is essential, particularly in patients with atypical features that mimic other rheumatologic disorders such as SLE or antiphospholipid antibody syndrome. This case highlights the importance of maintaining a high index of suspicion in those with negative initial autoimmune testing but characteristic cutaneous findings. Prompt initiation of immunosuppressive therapy and greater awareness of this entity are vital to improving patient outcomes. This abstract is funded by: None
Arora et al. (Fri,) studied this question.