What is Inflammatory Bowel Disease (IBD)?
You can have me read this article to you instead of reading it yourself…
Or you can read it the old-fashioned way below…
I’d imagine most everyone reading this page at this exact moment in time has already read plenty of other descriptions of IBD, UC, CD, IC, etc, etc. These readings likely included what they are, how they work, what the symptoms are, and so on and so forth.
But I think that you’ll find that this one is a little bit different. Consider this page the “Chelsey Take” on it all. Or, in other words: Brought to you from the mind of someone who has a chronic GI condition, but also has to spend her days talking to doctors.
Here goes.
Understanding an Inflamed GI Tract
A standard human gut on any given day is not inflamed. It will naturally undergo periods of inflammation that resolve themselves, and these can be caused by infections and particularly offensive food items.
So what is inflammation, you may ask?
Inflammation is the body’s overall attempt to eliminate any foreign invaders. Foreign invaders can include infections, such as viruses and bacteria, or they can include damaged tissues from our own bodies (think a really big cut or pre-cancer cells). In order to prevent these foreign invaders from wreaking havoc on the body, the body itself launches a protective attack that results in what we know as inflammation.
On a very basic level, inflammation is the recruitment of an army of cells to a certain location in order to fight those foreign invaders. In the vast majority of cases, this is a good thing – it keeps our infections from going unchecked and it allows our wounds to heal. But, sometimes the response can harm our healthy tissue. And sometimes it lasts for way too long.
The easiest reference point for inflammation is the redness, heat, swelling, pain, and discomfort that we might feel around a fresh cut that is infected. The heat that comes with a fever is also an inflammatory response (our bodies are trying to overheat the invader). Although you can’t see your GI tract in the same way, this is an apt way to consider what is happening in an inflamed gut. In fact, IBD is sometimes referred to as a digestive tract on fire.
Inflammation and Time
Inflammation can be both acute and chronic (and these two forms can overlap). Acute inflammation is what we are most used to in our everyday lives. We get a cut, our body attacks it, it heals up, and we go back to normal. Or, maybe we got an infection, our body attacked it, and a week or so later we started to return to our normal state.
Sometimes, however, the ‘foreign invader’ doesn’t respond quickly to the inflammation attack from our bodies. In these cases, an acute inflammation can become chronic. Another possible outcome from acute inflammation is scarring, or something called fibrosis. This means that the healthy tissue in the body became damaged from the inflammation, and now looks, and possibly also functions, differently. For instance, if the intestine becomes bulky and scarred, it may become clumsier at important tasks, like absorbing nutrients.
Chronic inflammation is something that lasts weeks to months to years. It involves a really strange combination of activities all happening at the same time – inflammation, tissue injury, and healing. We’ll come back to this point in a moment.
Inflammation Against the Non-Foreign Invader
If you’re here, you’ve already heard the term ‘autoimmune’. An autoimmune reaction is a situation in which the body launches an inflammatory attack against its own tissues. IBD is an autoimmune condition, which means the body is attacking its own gut.
This means that the body may think that it is attacking a foreign invader, when in reality it is attacking itself. There are many possible causes for this, and we discuss those here. The important takeaway is that over 90% of IBD cases are chronic, and this is simply because the target of the attack is not going anywhere – it is your intestine, a permanent resident.
We could launch into an overview of the cells that are involved in causing this inflammation and the details of what each one does, but I don’t think that adds any real value here. What is of value is understanding that the part of the body that is subjected to an autoimmune reaction is in a perpetual state of inflammation, tissue injury, and healing (fibrosis, scarring). Sometimes it will go into remission on its own. The treatments for IBD focus on forcing remission to happen when it doesn’t occur spontaneously.
Defining IBD
So that leads us specifically to defining IBD. IBD is an autoimmune condition that is characterized by chronic inflammation of specific parts of the GI tract. How and where this inflammation presents will lead to a classification of each person’s IBD.
Ulcerative Colitis
This particular form of IBD occurs only in the colon. One thing that is distinctive about this form of IBD is that it works its way consistently up into the colon from the rectum. There are no scattered patches of inflamed tissue. Instead there is one single stretch of inflamed tissue (think of somebody lighting a trail of gasoline on fire).
Some people will have larger sections of their colons impacted than others, but it is still considered ulcerative colitis in all of these cases.
Pancolitis is the most severe form of ulcerative colitis – it involves inflammation of the ENTIRE colon.
Crohn’s Disease
This particular form of IBD occurs anywhere in the GI tract. The most common location, by far, is the very end of the small intestine prior to meeting up with the colon (called the terminal ileum). Some people will experience this condition anywhere from the mouth to the anus, but again, the small intestine is the most common place.
Crohn’s is also distinctive from colitis because it can occur in patches. While colitis will run along a constant stretch of intestine like a fiery trail, Crohn’s can show up in different patches throughout (like little patches of weeds growing in someone’s otherwise perfectly manicured lawn). So there might be a completely healthy segment of small intestine that is surrounded by two very inflamed segments of small intestine – these are called “skip lesions”.
Indeterminate Colitis
While you would think that it should be pretty clear, then, whether the inflammation is ulcerative colitis or Crohn’s disease, there are cases where it is not clear at all. And those cases receive the frustratingly vague title of indeterminate colitis, which represent 5-15% of all initial IBD diagnoses.
Most of the time, this is a temporary label for cases experiencing incredibly severe inflammation. This severity prevents a physician from being able to tell where the inflammation started. In a way, it is like a building that has caught fire to the point where you cannot locate the source. A clear diagnosis can often be gained at a later time. This is also a more common diagnosis for children in which the nature of the condition is unclear. Again, this can later convert to a clear diagnosis.
Now What?
Altogether, it is estimated that there are just over 1 million cases of IBD in the United States (and obviously far more across the world). So let’s talk about the other important factors.
Interested in more information on IBD?
Next: What Causes IBD?
Or refer back to the IBD Info Hub.
Trivia and Terminology:
Autoimmune is a situation in which the body sees its own cells as foreign invaders and attacks them
Fibrosis is a situation in which tissue thickens and scars while healing
Pancolitis is a form of ulcerative colitis in which the entire colon is inflamed
Skip lesions are segments of healthy intestine in between inflamed intestine (occurs in Crohn’s disease)
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