[Aspects of pulmonary involvement in inflammatory bowel disease]

The incidence of pulmonary manifestations of inflammatory bowel disease (IBD) appears to be much higher than previously assumed. In prospective studies, subclinical pulmonary interstitial infiltrates or pathological lung function were found in 40%-60% of IBD patients, both in children and adults. Pulmonary disorders can affect any part of the respiratory system, the most frequent pattern being inflammation of the large airways often associated with bronchiectasis. The differential diagnosis should include drug-related pulmonary disease and infectious causes when receiving immunosuppressive therapy. The diagnostic approach consists of a thorough history and clinical status as well as lung function tests including body plethysmography and high-resolution computed tomography of the thorax. Bronchoscopy with broncheoalveolar lavage and sample collection for histology as well as exclusion of pulmonary embolism may be indicated. Pulmonary disease in association with IBD can develop at any time during the course of IBD: in rare cases, symptoms can evolve even before gastrointestinal symptoms appear. On the other hand, there are frequent reports on the occurrence of pulmonary inflammation after proctocolectomy in patients with ulcerative colitis. The pathophysiologic background is largely unknown, but there seems to be an interaction between gastrointestinal and pulmonary inflammation. The mainstay of therapy are inhaled or systemic corticosteroids. Most patterns of pulmonary involvement in IBD respond well to corticosteroid therapy. Rarely, serious and persisting complications occur, such as strictures or stenosis of the large airways.