Crohn's Disease: Differentiation and Diagnosis

Marla Dubinsky, MD: Crohn’s disease can present in many ways. I’ll start with the more classic way that Crohn’s disease would present. Patients would describe intermittent abdominal pain; they would have intermittent loose stool. Some patients, if it involves the colon, will actually have blood in their stool and frequent bowel movements and urgent bowel movements, but that’s a very colonic or colitis-like presentation. If you consider small bowel disease, which is quite common in Crohn’s disease, then there could be weight loss, anemia, fatigue, decreased energy, decreased appetite, abdominal pain, and change in their bowel consistency, potentially. But it’s important to note that the symptoms a patient presents with are dependent on the location of their disease.

Someone who presents with rectal bleeding, frequency, and urgency, the more colitis type, could have Crohn’s disease just of the colon. There is a subgroup of patients with Crohn’s disease who don’t have involvement of their small intestine. A lot of patients would say, “Well, I have both,” and I never quite understood what that meant. I think when you use the term “Crohn’s colitis,” people are so used to thinking colitis means ulcerative colitis. But colitis is just a disease location. It just means that the colon is inflamed.

That’s the more classic presentation. I would like to note that in pediatrics, unfortunately, Crohn’s tends to pop up right in the most important time in this transition of pubertal development and adolescence. Growth failure is one of the most important presentations of a pediatric patient, because that means their growth is stunted, and that means the inflammation has been around probably longer than they think. It was there even before the abdominal pain started, for example. So, we look at the growth chart and can see a flattening of the growth chart—no significant weight gain over the last year—and therefore, we know that there has been an impact on the absorptive capacity of a pediatric patient with their nutrition. And so, we’re really pressed for time to get that disease under control so that we can get them back on their growth curve, to go into puberty during the correct stages. For example, boys grow for a little bit longer than girls, so we have to know exactly where they are in that window. That’s a unique way that patients can present. Patients with Crohn’s disease, I should also add, can have perianal disease, which means fistulas, skin tags, fissures, or other things that are classic to perianal disease. Colitis patients don’t have perianal disease.

Stephen B. Hanauer, MD: Because Crohn’s disease is a systemic disease with a gut focus, we first and foremost look for systemic impacts of the disease. This can involve anemia, electrolyte abnormalities, malnutrition, or deficiencies in vitamin D and vitamin B12. There are blood tests that we do in many of these individuals. From a diagnosing-the-disease aspect, this is accomplished by a combination of endoscopy, either colonoscopy or upper endoscopy, with imaging of the middle part of the intestine that can’t be seen in routine endoscopies.

William J. Sandborn, MD: I’m often asked, “What is the differential diagnosis of Crohn’s disease in patients with GI tract findings and symptoms?” I always make the point that both Crohn’s disease and the related condition, ulcerative colitis, are syndromes. There’s not a molecular biology diagnosis or a specific test for either disease. So, in Crohn’s disease, you have to think it through. Is this ulcerative colitis, if the inflammation is confined to the colon? Is it infectious colitis? Might it be a drug-induced colitis from nonsteroidal anti-inflammatory drugs? The symptoms of Crohn’s disease, abdominal pain and diarrhea, can completely overlap with the symptoms of irritable bowel syndrome. And so, you have to work through that differential diagnosis.

Transcript edited for clarity.