A Case of Rapidly Progressive Interstitial Lung Disease Due to Antisynthetase Syndrome

ABSTRACT

Introduction: Antisynthetase syndrome is a rare autoimmune disease. Clinical characteristics include interstitial lung disease (ILD), myositis, Raynaud's phenomenon, mechanic's hands, and arthritis. The condition is characterized by antibodies targeting an aminoacyl transfer RNA synthetase. Compared to other inflammatory myopathies, there is a higher prevalence and increased severity of ILD. Case Report A 34-year-old female with a history of polycystic ovarian syndrome presented with progressive dyspnea during her third trimester of pregnancy. Initial computed tomography angiography (CTA) chest showed widespread multifocal and multilobar ground-glass opacities and nodular areas of consolidation. COVID-19 testing was negative. She went into preterm labor and delivered her baby at 30 weeks. About 10 days after delivery, her respiratory symptoms worsened. Transbronchoscopic lung biopsy was nondiagnostic. She subsequently underwent surgical lung biopsy which revealed organizing pneumonia and interstitial fibrosis. Laboratory studies revealed a high Jo-1 antibody of 1033U (normal less than 20U), positive ANA, creatine kinase 186 U/L, as well as aldolase 22.3 U/L leading to a diagnosis of antisynthetase syndrome. The patient continued to be dyspneic and developed increased oxygen requirements. Treatment was initiated with 1 dose of 125 mg of methylprednisolone followed by 1 g of methylprednisolone for 3 days, after which she was continued on oral prednisone. She was additionally started on 250 mg of mycophenolate mofetil. Despite these therapies she continued to have increased oxygen requirements, eventually requiring noninvasive positive pressure ventilation and ultimately intubation with mechanical ventilation. Chest x-ray demonstrated worsening bilateral patchy infiltrates. Given her clinical deterioration, she underwent 5 treatments of plasma exchange after which she received 1000 mg of rituximab. The patient improved on this therapy and was able to be extubated after 3 days. Her oxygen requirements subsequently decreased and she was discharged on a prednisone taper;mycophenolate with a goal dose of 1000 mg twice daily;and plan for continued rituximab infusions. At 2 months follow-up, the patient was doing well without the need for supplemental oxygen. Discussion: This case demonstrates a rare disease in a peripartum patient. A high suspicion for antisynthetase syndrome is required to initiate autoimmune testing, particularly since there can be ILD predominant phenotypes without significant evidence of a myositis. Treatment is not standardized but typically consists of corticosteroids and other immunosuppressive agents. In severe cases of antisynthetase syndrome that are refractory to initial corticosteroid therapy, therapeutic plasma exchange can be performed.