An Unusual Case of Interstitial Lung Disease as the Primary Presentation of Mixed Connective Tissue Disease in a Child with Sickle Cell Disease

Mixed connective tissue disease (MCTD) is an autoimmune disease associated with pulmonary manifestations. We report a case of a 15-year-old asymptomatic African American boy with sickle cell disease (SCD), diagnosed with MCTD-related interstitial lung disease as the primary diagnosis after a work-up for worsening pulmonary function tests (PFTs). To our knowledge, this is the first case of MCTD with primary pulmonary manifestations in a pediatric patient with sickle cell anemia with no respiratory symptoms, diagnosed with PFTs, serology, and biopsy. This case emphasizes the need of early pulmonary specialist involvement in SCD and autoimmune disease patients, and that periodic PFTs remain a very useful tool for early diagnosis and disease progression assessment.