Shrinking lung syndrome (SLS) associated with systemic lupus erythematosus (SLE): A series of cases in a university hospital

Introduction: SLS is a rare manifestation (0.6-13.5%) of SLE. It is suspected in patients with dyspnea and pleuritic pain, diaphragmatic elevation in thoracic images and a restrictive ventilatory defect. Objectives: Describe the clinical, radiological and functional features of a cohort of patients diagnosed with SLS; as well as its evolution in pulmonary function tests. Methods: A retrospective and descriptive review of the clinical histories of the patients diagnosed with SLS treated in the pulmonary and rheumatology division was conducted between 2009 and 2018. Demographic, clinical, functional, radiological, and treatment data were collected. Results: Out of a total of 225 patients diagnosed with SLE, 10 (4.44%) with SLS diagnosis were included. Mean age was 41.2 + - 16 years; 6 (60%) were women. The main symptom was dyspnea in 70 (70%). Two patients (20%) presented pleuritic pain. 9 (90%) presented decreased lung volumes and 5 (50%) laminar atelectasis. The mean FVC was 1.95l + -0.44 (50.5%); TLC 3.31l + - 0.47 (62.1%); DLCO 16.78 + -4.24 (68.2%); KCO (DL/VA) 5.62 + -1.28 (128%); maximal inspiratory pressure (MIP) 70.4 + -25.4 (72.6%); maximal expiratory pressure (MEP) 90.7 + -56.3 (84.6%). Corticosteroid treatment was used in 10 (100%) of the patients, associated with azathioprine in 3(30%). The mean FVC value after a median time of 27 months was 2.28 (58%); an improvement of 300 ml (7.7%) compared to the first FVC measurement was observed. Conclusions: The prevalence of SLS was 4.4%. The median time to diagnosis of SLS was 30 months. With the immunosuppressive treatment, a respiratory functional improvement was achieved.