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A1576 - When a Consolidated Lung Does Not Lead to a Consolidated Diagnosis: Antisynthetase Syndrome Presenting with Organizing Pneumonia
Author Block: A. Z. Alkhathlan1, A. Syed1, C. Donatelli2, C. V. Teba2; 1Internal Medicine, University Hospitals Cleveland Medical Center, Cleveland, OH, United States, 2Pulmonary and Critical Care Medicine, University Hospitals Cleveland Medical Center, Cleveland, OH, United States.
Introduction Organizing pneumonia (OP) is a form of non-infectious pneumonia with characteristic clinical, radiological, and histopathological findings. The diagnosis is often considered after multiple antibiotics have failed to treat a presumed infectious pneumonia. Antisynthetase syndrome (AS) is one of the rarest causes of OP and is associated with myositis, antisynthetase antibodies, and systemic manifestations. Case Presentation A 73-year-old female non-smoker, with controlled hypothyroidism and previously feeling well, was evaluated in an outpatient clinic for progressive dyspnea and cough despite antibiotic for community-associated pneumonia. Initial exam noted pulse oximetry 94% on ambient air, bibasilar crackles, and skin ulcerations mainly on 2nd and 3rd digits. Further questioning revealed several months of dry eyes, mouth, and scaly skin primarily on her hands. Chest x-ray demonstrated bilateral basilar opacities. Chest computed tomography showed dense bilateral lower lobe and lingula consolidations, enlarged mediastinal and hilar lymph nodes (Figure). Pulmonary function tests showed restriction, a reduced diffusing capacity, and oximetry testing showed desaturation with exertion to 79%, requiring 2 L/min. Diagnostic workup included bronchoscopy, bronchoalveolar lavage (BAL), cytobrushings, and transbronchial biopsies from the left lower lobe. BAL revealed 588 nucleated cells with 37% neutrophils, 18% lymphocytes, 40% monocytes and 5% eosinophils. Cultures and cytology samples were negative for infection and malignant cells, lung biopsy showed acute and chronic inflammation consistent with organizing pneumonia. Serum lab tests including ANA, C-ANCA, P-ANCA, and anti-histone antibody were negative. Erythrocyte sedimentation rate was normal, and C-reactive protein of 1.2 mg/dL was equivocal. Creatine kinase was 1323 U/L and aldolase 27 U/L—both significantly elevated. Rheumatology evaluation confirmed mechanic’s hands, no muscle weakness, and myositis panel was positive for anti-threonyl-tRNA synthetase (anti-PL-7) antibody, diagnostic of antisynthetase syndrome presenting with organizing pneumonia. High-dose corticosteroids were initiated and slowly tapered, with significant clinical and radiographic improvement at eight-months follow-up and she was eventually started on steroid-sparing agent azathioprine. Discussion This case is a rare presentation of anti-PL-7 AS presenting with biopsy-proven OP. Prior cases describe anti-PL-7 AS manifesting as nonspecific interstitial pneumonia. Idiopathic inflammatory myopathies are rare disorders characterized by muscle inflammation and involvement of other organ systems. A combination of polymyositis or dermatomyositis, antisynthetase antibody, with lung involvement, and other systemic symptoms is the antisynthetase syndrome. This case highlights the need for a high index of suspicion for OP in patients who fail antibiotic therapy for presumed pneumonia and have systemic signs concerning for mixed connective tissue disorders.