Confessions of a Wayward Diagnostician:

Reflections on the Irritable Bowel Syndrome

By Andy Bailey, M.D.

It is always good to think out loud with patients as we try to figure out the cause of their symptoms. If nothing else, it reassures the patient that we are indeed thinking about them and not daydreaming about our next golf game. It also lets them know that, despite our claims to the contrary, medicine is still as much an art as it is a science. We deal with diagnostic uncertainty more often than we care to admit.

The single biggest misconception we deal with, I think, is that the Irritable Bowel Syndrome (IBS) is a vast diagnostic wasteland. "Got belly pain or irregularity? All your tests are negative? Well, I don't know what you have, so it must be IBS."

IBS has diagnostic criteria, and the diagnosis can be made proactively in the majority of cases. Is there belly pain relieved with bowel movements? Is it associated with a change in the appearance or frequency of the stool? Does the patient pass mucus with the stool? Does the patient have a feeling of "incomplete evacuation?" Are these symptoms chronic and possibly intermittent, going back a year or two or even more? Say yes to enough of these questions and it is looking more and more likely that the patient has IBS.

People frequently say, "That's fine, doctor, but I have a neighbor who had the same symptoms and he ended up having Crohns disease/colon cancer/gall bladder disease/etc." The patient's concern is fair enough. The typical symptoms of IBS, including abdominal pain, abnormal bowel function, bouts of diarrhea and/or constipation are not unique to IBS. It is important to reassure the patient that we are not overlooking a more serous diagnosis.

If your symptoms start relatively later in life (over 40 or 50), that will catch our attention. If there is blood in the stool, a history of fever or weight loss, or if the abdominal discomfort awakens the patient out of a sound sleep in the middle of the night, we're going to be thinking of diagnoses other than IBS. Do you have a family history of colon cancer, polyps, ulcerative colitis or Crohns disease? Have you traveled outside the country lately? Do you drink water that hasn't been purified? Say yes to any of the above and we're going to be considering alternate diagnoses.

Are your symptoms provoked with consumption of generous quantities of dairy products? Are there a lot of the sweeteners, sorbitol, xylose or fructose in your diet? Do you get a little carried away in your consumption of white flour products? Perhaps your diarrhea and cramping are due to intolerances to these substances and your symptoms may go away with simple dietary avoidance or reduction.

Fancy testing isn't often necessary, but some testing can be very helpful. A blood count can let us know if you have anemia or evidence of inflammation; these are not seen in straightforward IBS. Testing the stool for hidden blood should be performed. Any blood in the stool raises concern for colitis, polyps and even cancer. If you're over 50 we're going to recommend colonoscopy. It is a good idea to screen for colon cancer at that age even if you are not having any symptoms. Even if you're quite a bit younger than that your doctor may consider colonoscopy.

When have we erred in the diagnosis of IBS? Celiac disease (a type of wheat allergy) can mimic the symptoms of IBS to the point that I now screen for it with blood tests as part of the routine evaluation. Young women who have a great deal of pain might just have endometriosis, so I try to keep the lines of communication with their gynecologist open. Patients with diverticulosis can be tough to sort out, too. Does the pain represent diverticulitis (actual infection and inflammation of the diverticuli) or just a spasm? Sometimes imaging studies such as CT scans don't help us as much as we'd like.

I would love to state truthfully, especially in a public forum, that I have never misdiagnosed mild Crohns disease as IBS. But I have, and I think just about any diagnostician who deals with the evaluation of abdominal pain or diarrhea has as well. It can be very difficult to tell the difference between mild Crohns disease and IBS. If your symptoms worsen or just don't respond to any of the therapy for IBS or if you develop new symptoms, go back to the doctor. He or she can always rethink your situation.

Andrew Bailey, M.D., is a graduate of Davidson College and Vanderbilt University School of Medicine. He did his postgraduate training at Brooke Army Medical Center in San Antonio , Texas and is board-certified in both Internal Medicine and Gastroenterology. He has practiced in Louisville since 1990.