Crohn’s disease is a chronic, or ongoing, disorder that causes inflammation of the gastrointestinal tract. While it primarily causes ulcerations in the small and large intestines, it can affect any part of the digestive system, from the mouth to the anus.
The fact that Crohn’s disease can affect any part of the digestive tract is what differentiates it from another inflammatory bowel condition called ulcerative colitis.
Ulcerative colitis affects the colon which is the large intestine. Any portion of the large intestine can be involved. About a third of patients have just the lower third - what's known as the rectum involved. Another third of patients will have the rectum and left side of the colon. And finally, in about one third of patients, the entire colon is involved.
On Camera: It's particularly important to make the right diagnosis between Crohn’s disease and ulcerative colitis in patients that have only colonic inflammation. And the reason it's important is that once we've tried all of the medicines that we have available to us, if you're not responding, or the person isn't responding to these medicines, the next option is to have surgery.
In a normal, healthy person the immune system protects the body from harmful elements like bacteria, viruses, and fungi. When the immune system activates its immune cells and proteins to do battle, it causes inflammation at the site. In Crohn’s disease there is a loss of regulation of the immune system within the intestinal tract and it cycles between periods of great activity, ulceration, and periods of relative calm or remission.
There are different types of Crohn’s disease and the different types may present with different findings and different complications.
One type of Crohn’s disease is inflammatory in nature and it results in small erosions and breakdown of the lining of the bowel wall. Another type of Crohn’s disease is what we call fibrostenotic, which tends to be more scar tissue forming. So the inflammation is healed by the body but the resulting scar tissue can cause obstructive types of symptoms where the bowel is not moving properly. And the third type of Crohn’s disease is what we call penetrating, and that means that the inflammation goes right through the wall of the bowel and has a tendency to form connections between loops of bowel or connections between the bowel and other organs or the skin. So the different types of Crohn’s disease present in slightly different ways.
It's important to diagnose Crohn’s disease early because Crohn’s disease is a progressive disease. And in some people the Crohn’s disease can progress very rapidly to complications such as narrowing of the small intestine leading to blockages, or perforation of the small intestine requiring surgery.
It is estimated that nearly half a million Americans suffer from Crohn’s disease. The condition affects both men and women equally, and onset usually occurs between the ages of 15 and 35.
Crohn’s disease historically was first noted to be prevalent in the Ashkenazi or European Jewish population—more prevalent than other Caucasian populations in Europe. But what we've seen is that the worldwide distribution of Crohn’s disease really affects all races and ethnicities and appears to be a disease more of first-world nations probably related to hygiene more than genetics alone.