Systemic Lupus Erythematosus Complicated by Shrinking Lung Syndrome Treated With Belimumab: A Case Report

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SESSION TITLE: Inflammatory Diseases Affecting the Lung SESSION TYPE: Student/Resident Case Report Slide PRESENTED ON: Monday, October 24, 2016 at 11:00 AM - 12:00 PM INTRODUCTION: Cardiopulmonary symptoms occur in up to 60% of patients with Systemic Lupus Erythematosus (SLE). Shrinking Lung Syndrome (SLS) is a rare complication of SLE where patients present with restrictive lung disease without imaging findings. We report a case of new onset SLS while receiving hydroxychloroquine, mycophenolate and prednisone treated successfully with belimumab. CASE PRESENTATION: A 44-year old woman with a history of SLE, Lupus Nephritis Class IV-V, presented to the Rheumatology Clinic with dyspnea on exertion. She had recently completed 6 cycles of cyclophosphamide induction therapy for lupus nephritis and was receiving hydroxychloroquine, mycophenolate, and prednisone. Physical examination was unremarkable. SLE Disease Activity Index score was unchanged from the previous visit. Imaging of the chest was perfomed to rule out life threatening conditions. Computerized Tomography Angiography failed to reveal parenchymal pulmonary disease or pulmonary artery filling defects. However, pulmonary function testing (PFT) showed a restrictive pattern with impaired diffusion capacity. To evaluate for diaphragmatic paralysis, seated and supine PFTs were performed which did not show Forced Vital Capacity (FVC) changes in supine position. ECG, echocardiogram and nuclear imaging failed to reveal cardiac causes of dyspnea. Afterwards, the differential diagnosis was narrowed to: SLS, myasthenia gravis, and steroid-induced myopathy. CPK level was slightly increased and anti-acetylcholine receptor antibody was negative. Since the patient had no weakness, myopathy was thought to be unlikely. Belimumab was chosen as a steroid sparing agent. The patient reported resolution of dyspnea after initiating therapy. Her exercise tolerance returned to baseline and repeat PFT showed a persistent restrictive pattern with increased TLC. DISCUSSION: Several hypotheses have tried to explain the findings of SLS but the primary mechanism remains unclear. Our patient developed SLS while undergoing therapy with hydroxychloroquine, mycophenolate and prednisone. Belimumab was used as a steroid sparing therapy. Belimumab, a B Cell Activating Factor, is a new drug in the armamentarium against SLE. The optimal treatment for SLS is not yet determined. Treatment options range from prednisone as first line agent to rituximab as used in some case reports. After treatment with belimumab our patient achieved symptom resolution, increased exercise tolerance, improved VC and TLC. While the mechanism of SLS is poorly understood, B cells likely play a significant role as suggested by positive outcomes with rituximab and belimumab. CONCLUSIONS: Belimumab represents a new weapon against SLE and showed improvement of symptoms and lung volumes after treatment in a patient with SLS. Reference #1: Langenskiöld, E., et al. (2012). Shrinking lung syndrome successfully treated with rituximab and cyclophosphamide. Respiration; International Review of Thoracic Diseases, 84(2), 144-9. http://doi.org/10.1159/000334947 DISCLOSURE: The following authors have nothing to disclose: Felix Reyes, Deana Lazaro No Product/Research Disclosure Information