Background: Extraintestinal manifestations are common among patients with inflammatory bowel disease (IBD), whereas pulmonary involvement is considered rare. However, chronic lung diseases begin with subclinical changes of the small airways and often originate in childhood. Pulmonary involvement, particularly of the small airways, can be assessed using novel inert gas washout tests.
Methods: In this prospective, single-center study, 30 children and adolescents (mean age, 14 years; SD, ±2.6; 13 boys) with IBD (mean disease duration, 3.2 years; SD, ±2.8), and 32 healthy age-matched controls, performed nitrogen multiple-breath washout, double-tracer gas single-breath washout, and diffusion capacity for carbon monoxide. Patients with IBD additionally performed spirometry, plethysmography, and measurement of exhaled nitric oxide.
Results: Patients with IBD demonstrated no abnormalities in classical lung function tests. There was no difference between active disease and remission. The lung clearance index, a very sensitive indicator for small airway function, did not differ between patients with IBD and healthy controls (mean difference [95% confidence interval] -0.01 [-0.28 to 0.25]). Specific markers for peripheral lung ventilation (Sacin and Scond) were also within the normal range (0.002 [-0.003 to 0.008] and -0.002 [-0.020 to 0.015], respectively). No association was found between measures of lung function and IBD subtype, clinical disease activity scores, laboratory values, treatment modalities, or disease duration.
Conclusions: In our cohort of pediatric and adolescent patients with IBD without respiratory symptoms, there was no evidence of significant lung disease on extensive screening testing. General screening of asymptomatic patients therefore appears unnecessary and is not recommended in this population.