Crohn’s Disease: The Basics
Crohn’s Disease is a form of Inflammatory Bowel Disease, or IBD. The other form of IBD is called Ulcerative Colitis, which you can read about here. Read more about IBD in general here, and remember that IBD is very different from IBS, which stands for Irritable Bowel Syndrome, which you can read about here.
Crohn’s Disease can involve any part of the digestive tract, from mouth to anus. Now that doesn’t mean it DOES involve the whole tract- just that it CAN. The most common part of the digestive tract to be affected by Crohn’s is called the terminal ileum, and it’s the very end of the small bowel, right where it connects to the appendix and large intestine (also called the colon). Some people only have Crohn’s involving the colon, some people have it involving only the small bowel, some people have it involving segments of both. It’s rare, but some people have Crohn’s disease affecting their upper GI tract, like their stomach or esophagus.
Symptoms of Crohn’s can vary, depending on what part of the digestive tract is involved.
Typically, Crohn’s of the ileum or small bowel presents with belly pain and watery diarrhea. If the Crohn’s involves the colon, there can be blood in the stools, or even constipation.
One last point about Crohn’s is that it’s a “full thickness” disease, meaning it involves all layers of the wall of the digestive tract.
If you think of the digestive tract as garden hose running from mouth to anus, it means that the inflammation isn’t limited to the inner lining of the hose – the whole rubber can be affected, and this can sometimes lead to complete breakdown of the wall of the hose. Now the wall of the digestive tract serves a really important function in the body – it keeps poop and bacteria contained. So when there’s loss of integrity of that wall, bacteria can seep out and lead to infections. It can also the make the wall very sticky, and it can stick to other nearby structures within the belly, like the uterus, bladder, or other loops of bowel. These connections are called fistulae and can lead to unique problems of their own. Sometimes these fistulae can pop out to the skin. The skin around the anus, vagina and perineum are particularly susceptible.
When some of these “full thickness” complications heal, they can lead to scarring. Instead of the garden hose, think of the digestive tract as a floppy, deflated balloon. It’s build like this so that it can accommodate “traffic” – digested food and water flowing through it. Once there’s scarring, the wall of the balloon becomes stiff, so when you try to blow it up, that section doesn’t. This is called a stricture, and can lead to food, stool or even air getting stuck, causing what called an obstruction.
Lastly, symptoms of IBD aren’t limited to the digestive tract. IBD can cause fevers, low blood counts and poor nutrition, which can lead to weight loss and feelings of low energy and fatigue. Sometimes people with IBD can develop rashes, skin lesions, and problems with their eyes and joints.
If you are having symptoms or are concerned about IBD, you should consult with you doctor to see if any further testing is warranted.