Pulmonary Crohn's Disease in Down Syndrome: A Link or Linkage Problem.

Crohn's disease (CD) is an autoimmune inflammatory disorder that primarily affects the gastrointestinal tract. It may have pulmonary involvement, which has been rarely reported in pediatric patients. Down syndrome (DS) has been associated with increased frequency of autoimmune diseases. However, associations between CD and DS have been rarely reported. We present the case of a 5-year-old girl with known DS and a history of chronic intermittent abdominal pain who presented with persistent pneumonia. Her workup included a chest computed tomography (CT) scan that showed multiple noncalcified pulmonary nodules. An extensive infectious workup was done that was negative. CT-guided needle biopsy of the lung nodules showed necrotizing granulomas. This raised concern for primary CD with extraintestinal pulmonary manifestation. An esophagogastroduodenoscopy and colonoscopy were performed, and colon biopsies showed scattered epithelioid granulomas. Based on this information, there was consensus that her lung nodules were secondary to CD. She was started on standard therapy for CD, and her abdominal and respiratory symptoms gradually improved. However, she continues to have mild residual lung calcification and fibrosis. To our knowledge, this is the first reported case of pulmonary CD in a child with DS. The natural history of pulmonary CD in the pediatric population is not very well studied. Furthermore, since DS has been well known to be associated with increased frequency of malignancies and autoimmune conditions due to immune dysregulation, it is difficult to predict the severity and possible complications in this patient.