Crohn's disease

Crohns Disease

This is a chronic granulomatous disease that typically affects the terminal ileum and well demarcated areas of large bowel with relatively normal bowel disease. It can sometimes affect bowel elsewhere. It is often associated with auto-immune type features outside the bowel.

The disease has long been suspected by being due to a Mycobacteria because of the similarity of many features to human tuberculosis and vetinary Ovine Jonnes Disease, but to date no specific organism has been detected. It is probably a combination of an infection from one or several organisms together with an altered immune response.

The bowel show segmental "hose pipe" thickenning and shows full thickness chronic inflammation, giant cell granulomas, and fissures with acute inflammation. Bowel obstruction is common. This may require surgical resection and some patients eventually get a "Short bowel syndrome".

Treatment to date is fairly unsatisfactory. It does not seem to have the risk of malignancy associated with Ulcerative colitis.

The classic cases of Crohn's and Ulcerative colitis are distinct disease but in practice there are often "overlap" cases of chronic inflammatory bowel disease.