Shrinking lung syndrome (SLS) is a rare manifestation of systemic lupus erythematosus (SLE), characterized by decreased lung volumes and extra-pulmonary restriction. The aim of this study was to describe the characteristics of SLS in our lupus cohort with emphasis on prevalence, presentation, treatment and outcomes.
Patients and methods
Patients attending the Toronto Lupus Clinic since 1980 ( n = 1439) and who had pulmonary function tests (PFTs) performed during follow-up were enrolled ( n = 278). PFT records were reviewed to characterize the pattern of pulmonary disease. SLS definition was based on a restrictive ventilatory defect with normal or slightly reduced corrected diffusing lung capacity for carbon monoxide (DLCO) in the presence of suggestive clinical (dyspnea, chest pain) and radiological (elevated diaphragm) manifestations. Data on clinical symptoms, functional abnormalities, imaging, treatment and outcomes were extracted in a dedicated data retrieval form.
Twenty-two patients (20 females) were identified with SLS for a prevalence of 1.53%. Their mean age was 29.5 ± 13.3 years at SLE and 35.7 ± 14.6 years at SLS diagnosis. Main clinical manifestations included dyspnea (21/22, 95.5%) and pleuritic chest pain (20/22, 90.9%). PFTs were available in 20 patients; 16 (80%) had decreased maximal inspiratory (MIP) and/or expiratory pressure (MEP). Elevated hemidiaphragm was demonstrated in 12 patients (60%). Treatment with prednisone and/or immunosuppressives led to clinical improvement in 19/20 cases (95%), while spirometrical improvement was observed in 14/16 patients and was mostly partial.
SLS prevalence in SLE was 1.53%. Treatment with glucocorticosteroids and immunosuppressives was generally effective. However, a chronic restrictive ventilatory defect usually persisted.