Rapidly Progressive Cellular NSIP in a Young Female Found to Have Antisynthetase Syndrome

ABSTRACT

Introduction: Antisynthetase syndrome(ASS) is a rare autoimmune disease characterized by myositis, arthritis, cutaneous findings and interstitial lung disease (ILD). In 15-30% cases of ASS, ILD can be the presenting feature making this a very challenging diagnosis to make, especially during the COVID 19 pandemic. We present a unique case of ILD as presenting feature of ASS. Case A 31 yr old female, never smoker, with asthma and obesity was referred to the pulmonary clinic for dyspnea of 2 months. Dyspnea was on exertion, associated with cough and pleuritic chest pain. Oxygen saturation on exam was 91% at rest and 86% on exertion. PCR and antibodies for COVID was negative. CXR showed bilateral infiltrates. She was treated with several courses of antibiotics and steroids. Her symptoms improved with steroids yet returned when course completed. Chest CT revealed bilateral parenchyma opacities with sparing of the lung apices. This was repeated 3 months after her course of antibiotics and steroids which revealed worsening of ground glass opacities, now diffuse with areas of organizing pneumonia. Bronchoalveolar lavage showed alveolar macrophages with a mixture of acute and chronic inflammatory cells. PFTs revealed severe restrictive lung disease. Infectious work up including bacterial, viral and fungal causes was negative. Complete blood count with differential was normal. B-type natriuretic peptide, creatine kinase, liver function test, basic metabolic panel, HIV and fungal serologies were unrevealing. A rheumatologic work up revealed elevated ESR (48), CRP (6.9), aldolase (48) with positive anti OJ antibodies. She underwent VATs with wedge lung biopsy which revealed cellular non specific interstitial pneumonia (NSIP). She was diagnosed with ASS and started on a gradual taper of high dose steroids and steroid sparing agent Mycophenolate Mofetil. With time her respiratory symptoms improved and she no longer required supplemental oxygen. She was enrolled in pulmonary rehabilitation and encouraged to loose weight as her BMI of 55 could preclude lung transplantation if needed. Discussion: ASS is a rare autoimmune connective tissue disorder characterized by myositis, polyarthritis, cutaneous findings and ILD. It occurs more commonly in women with average age of onset in 50s. ILD has been reported in 69-100% with NSIP being most common followed by cryptogenic organizing pneumonia and UIP. Treatment consists of steroids, with or without a steroid-sparing agent. Timely diagnosis of ASS is imperative for patients presenting with ILD as delay can lead to progression of ILD which serves as a predictor for morbidity and mortality. (Figure Presented).