Three-Year Diagnostic Delay in Shrinking Lung Syndrome: Rituximab-Theophylline Combination as Rescue Therapy

Shrinking lung syndrome (SLS) is an infrequent complication of systemic lupus erythematosus (SLE). A 41-year-old woman with a 10-year history of SLE presented with dyspnea, chest pain, and dry cough. She had poor medication compliance and multiple hospitalizations over 3 years for similar symptoms, without a definitive diagnosis. Imaging revealed bilateral basal atelectasis and an elevated right hemidiaphragm, while pulmonary function tests (PFTs) showed a restrictive pattern. Other lung and cardiac conditions were excluded, leading to a diagnosis of SLS. Treatment with rituximab, prednisolone, and theophylline improved PFTs, chest pain, cough, and dyspnea at follow-up. Clinicians should consider SLS in SLE patients with dyspnea and characteristic imaging, as delayed diagnosis may increase morbidity.