Inflammatory Bowel Disease Part 1

Posted by Aaron

Wednesday, March 3, 2010

As I started writing this, I began to wonder why it is I seem to spend so much time talking about poop. I pondered the poop for a while and have determined that I am not, in fact, obsessed with the tailpipe. Vomiting and diarrhea are far and away one of the most common complaints we see. I can't decide if scratching/itching/ears are more common or it it's vomiting/diarrhea. So although I may seem to blog often on puke and poo, there's a reason. It's what I see all day :)

I wanted to discuss IBD because it is probably one of the most abused diagnoses I see. I'm guilty of it as well. Basically, if we can't identify specifically what's going on and it's a chronic problem, we like to label it IBD. It's easy. It's only three letters.

The total post became too long, so I've decided to break it up into three parts. Today's post is talking about what causes IBD. Tomorrow will be how to diagnose. Friday's post will be treatment options.

So what is REAL Inflammatory Bowel Disease? In its purest sense, it is EXACTLY that. But it's not that simple. (Nothing ever is, right?) Keep in mind that your gut has more surface area (by FAR) than does your skin. By default, this means that there is quite a bit of your immune system involved in policing the surface area of the gut. So let's go back to the basics. What causes inflammation?
  • Parasites. giardia, coccidia, cryptosporidium, hookworks, and whipworms start the list. These parasites each attack separate portions of the gut and their specific symptoms depend of severity. The moral of the story is that they body react to a parasite and there is inflammation generated at the site of parasitic infection. Imagine the mosquito bite or the cut/scratch you see on your skin. Imagine that same thing happening (albeit microscopically) in the gut. Same idea.
  • Dietary problems. True food allergy is a major cause of IBD and it is, IMHO, one of the more common problems. Food allergies can be insidious and kind of "creep up" on you. Owners say, "he's always eaten this food so it can't be food allergy." Nope, wrong. Food allergies almost always develop over time after chronic exposure to the same protein. Meat proteins are more likely to be the culprit. Folks like to blame grains. From what we understand now, grains are less frequently a problem than are the major meat proteins. In other words, beef, chicken, eggs, soy are more likely a problem than corn, wheat, barley, or rice. The other really important point about diet is that abrupt CHANGES in diet can also trigger inflammation. If your body is not adjusted to digesting a particular food, it can cause incomplete digestion and this can trigger issues like bacterial overgrowths or excessive stimulation of gut contractions.
  • Stress. This is more a problem in people than in pets, but I think more cats are affected by stress than we truly appreciate. Chronic stress causes chronic increases in stress hormones like cortisol. There are also increases in the body's autonomic nervous system and you get increases in epinephrine and norepinephrine (adrenalin). These nervous signals cause changes in gut motility. Parts of the gut may contract more than they should, others may not contract at all. The result is poor digestion, unpredictable absorption of nutrients, and inappropriate populations of bacterial growth.
  • Bacterial overgrowth. This is very hard to prove. You are covered from head to toe in bacteria and your intestines are no exception. The balance of bacteria in the gut plays a big role in how "happy" your gut is and how well you digest your food. There are "good bacteria" that play a positive role in your immune response, and there are "bad bacteria" that tend to generate lots of upset.
Now you see why a simple diagnosis of IBD isn't so simple? Do you also see why it is often easier to just label the problem IBD and not try to figure out EXACTLY what is causing the problem?

The even more confusing part (and you may have been thinking of this as you read through the list above) is that problems listed above are rarely mutually exclusive. Food indigestibility can be caused by the presence of a parasite and the bacterial overgrowth that occurs with the indigestion is what causes much of the symptom. It's rarely as simple as problem 1 causes symptom A and so we treat for problem 1 and it all goes away. It's the onion analogy. We have to start peeling back the layers to get to the bottom of it.

Tomorrow - Diagnosis.