Shrinking lung syndrome associated with systemic lupus erythematosus

Introduction: Shrinking lung syndrome (SLS) is a rare and less-known manifestation of systemic lupus erythematosus (SLE). The aim of this study is to describe the demographic, clinical, functional, imaging characteristics, and treatment received in a cohort of patients diagnosed with SLS. Methods: Clinical records were reviewed retrospectively in a cohort of patient with SLE and SLS followed- up prospectively between 2007 to 2023 in the Rheumatology and Neumonology Units. Results: Eleven SLS patients (10.3%) of 107 SLE patients were diagnosed. They were 81.8% female and 18.2% male. Median age was 30 years old (RIQ = 25-75% [25.5-41.5]). Clinical symptoms were dyspnea (72%), pleuritic pain (36%), but 27.3% of patients were asymptomatic at diagnosis. Respiratory functional evaluation was, median FEV1 1 / FVC : 86% (RIQ = 82-90), median FVC: 61% (RIQ = 38.5-71), median DLCO: 65% (RIQ = 48-69) and median DLCO/VA: 95% (RIQ = 89-106). High-resolution computed tomography of thorax (HRCT) showed atelectasis (54.5%), diafragmatic elevation (27.3%), normal (27.3%) and pleural effusion (9%). Patients were treated with systemic corticosteroids (100%); in 72.7% of them, associated to other immunosupressives: methotrexate (36%), mycophenolate (27.3%), hydroxychloroquine (27.3%) and azatioprine (18.2%). Conclusion: SLS prevalence was 10.3%, higher than reported in other studies of SLE. Dyspnea was the most clinical symptom. Suspicion of moderate restriction were determined with mild deterioration of DLCO. Atelectasis was the most frequent HCRT sign. Immunosupressive treatment was prescribed in all patients with systemic corticosteroids associated to other drugs.