From the Guidelines
Crohn's disease is associated with several interstitial lung diseases (ILDs), primarily including bronchiolitis, organizing pneumonia, granulomatous lung disease, and non-specific interstitial pneumonia, with a typical age of onset between 25 and 45 years. These pulmonary manifestations can develop at any time, but often occur after the intestinal disease has been established, as seen in a study of 11 patients with Crohn disease, where cough was among the presenting symptoms in six patients 1. The pathophysiology connecting Crohn's disease to these pulmonary manifestations involves shared immune dysregulation and inflammatory pathways, with TNF-alpha and other cytokines playing key roles in both intestinal and pulmonary inflammation. Some key points to consider include:
- The lung involvement can occasionally precede gastrointestinal symptoms, as reported in a series of patients with Crohn disease, where respiratory problems developed postcolectomy in some cases 1.
- The respiratory symptoms may be subtle and overlooked amid gastrointestinal complaints, so clinicians should maintain a high index of suspicion for pulmonary involvement in Crohn's patients presenting with unexplained respiratory symptoms.
- Treatment typically involves corticosteroids and immunomodulators already used for intestinal disease management, with medications like infliximab often addressing both gastrointestinal and pulmonary manifestations simultaneously, as suggested by the improvement in patients with ILD and necrotic nodules who received systemic corticosteroid therapy 1. The variable histologic appearances in patients with Crohn disease are similar to those encountered in patients with ulcerative colitis, including chronic bronchiolitis with nonnecrotizing granulomatous inflammation, acute bronchiolitis associated with a neutrophil-rich bronchopneumonia and vague granulomatous features, cellular interstitial pneumonia with rare giant cells, and organizing pneumonia with focal granulomatous features 1.
From the Research
Interstitial Lung Diseases Associated with Crohn's Disease
- Cryptogenic organizing pneumonia (COP) 2
- Usual interstitial pneumonitis (UIP) 3
- Bronchiolitis obliterans organizing pneumonia (BOOP) 3, 2
- Eosinophilic pneumonia 3
- Langerhan's granulomatosis 3
- Non-necrotizing granulomatous inflammation mimicking sarcoidosis 4
Typical Age of Onset
- The age of onset for these interstitial lung diseases in patients with Crohn's disease is not consistently reported in the provided studies.
- However, one case report mentions a 29-year-old man with Crohn's disease who developed cryptogenic organizing pneumonia 2.
- Another case report describes a 60-year-old female with a history of Crohn's disease who presented with interstitial lung disease mimicking sarcoidosis 4.