Crohn's disease

Crohn's Dieaseis 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 typically first appears in a sufferer by age 30 or so, though it is not unknown for symptoms to first appear quite late in life. It quite commonly appears in childhood. Some estimates suggest that up to 1,000,000 Americans have the disease, suggesting that the prevalence of it is around 1 in 300.Some ethnic groups have significantly higher rates of prevalence than others.

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".

The resulting symptoms include severe diarrhea and disrupted digestion, making it difficult for sufferers in the acute phase of the disease to eat and/or digest food. The inflammation can be extremely painful and debilitating.

Due to the lack of determination of a specific cause or causes, treatment for Crohn's is largely symptomatic. Patients are treated with anti-inflammatory drugs that act in the lower intestine, and, if symptoms cannot be controlled with other drugs, with steroids (though because of the side effects they are only prescribed for long-term use if nothing else works). Some patients can be treated with the existing drugs quite effectively and can go into long-term remission, sufficient to allow the sufferer to lead a normal life. Patients are at somewhat larger risk of colon cancers, and consequently undergo regular colonoscopies both to check for precancerous growths and to monitor the success of treatment. It does not seem to have as great a risk of malignancy compared to 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.