Respiratory Involvement in Children with Inflammatory Bowel Disease

Inflammatory bowel diseases (IBDs), including Crohn's disease and ulcerative colitis, are systemic diseases with a variety of extra-intestinal manifestations. Respiratory involvement, whether clinically symptomatic or latent, may be more common than previously thought. As opposed to adults, most of the cases in children involve Crohn's disease. The pathogeneses of the pulmonary manifestations are obscure. The inflammatory process is not restricted to the bowel as has been suggested by findings of high levels of fractional exhaled nitric oxide (FeNO) in the airways. Increased FeNO has been reported even during clinical remission, while increasing further during exacerbations. Pulmonary manifestations develop usually after the onset of the bowel disease; however, they may emerge after colectomy and cessation of therapy. Pulmonary lesions in children usually involve the lung parenchyma with granulomatous infiltrates. Other less common injuries involve the airways and the pleura. The most prevalent pathologies in adults are bronchiectasis, cryptogenic organizing pneumonia, and small airway disease. Pulmonary involvement in IBD is often latent or sub-clinical and may be detected solely by laboratory or imaging techniques. Abnormalities in pulmonary function tests (PFTs) are not consistent except for low-diffusion capacity for carbon monoxide, which was found in both children and adults. High-resolution computed tomography (CT) is a sensitive tool for detecting lung involvement and may reveal abnormalities even when PFTs are normal and the patient is asymptomatic. Medications used for IBD, especially nonsteroidal anti-inflammatory drugs, are also a risk factor for lung injury. Treatment of pulmonary involvement often includes systemic corticosteroids with subsequent prolonged treatment of inhaled steroids in appropriate selected cases. Other immune-modulators have been tried. Pediatricians, especially those treating children with IBD, pediatric gastroenterologists, and pediatric pulmonologists should have a high index of suspicion and be aware of tools to be used in the assessment and treatment of pulmonary complications in IBD.