Characteristics and Complications of Crohn's Disease

Bruce E. Sands, MD: Crohn’s disease is characterized by a severe and often unremitting inflammation that can occur anywhere in the GI tract, but it has a predilection for the distal small bowel and the proximal large bowel. But as every medical student learns, it can affect any part of the digestive system. It often involves the full thickness of the bowel, and that can lead to complications of disease over time.

Unfortunately, Crohn’s disease can damage the bowel beyond the mucosa as it is a full-thickness inflammation. Therefore, over time, that inflammation can evolve to stricture formation, which will lead to bowel obstruction. It can also penetrate through the serosa and invade adjacent organs to create fistulization, either to the skin between loops of bowel, to the bladder, to the vagina, or really to any other adjacent organ.

William J. Sandborn, MD: I’m often asked, “Why does Crohn’s disease relapse and then sometimes go into remission? And how does it progress over time?” What we see is that when patients are first diagnosed, about 90% of patients have ulcers in the lumen without the complications of stricture, fistula, and abscess. They will have symptoms with that. And then, over time, if the mucosa is not healed with various therapies, you’ll see ulcers progress into complications. So, fibrosis can occur with stricture and bowel obstruction, as well as penetration of the ulcers, leading to fistulas and abscesses.

An interesting item to consider is how you think of the severity of Crohn’s disease. On the one hand, you can have relatively mild symptoms with just mild abdominal pain or diarrhea. On the other hand, you can have very severe symptoms, not just severe and debilitating pain and diarrhea but also complications like anemia, malabsorption from surgical resection, and short bowel syndrome—just the inability to eat and malnutrition, symptoms on that basis. So, there’s quite a wide spectrum of disease.

Stephen B. Hanauer, MD: Crohn’s disease is a chronic inflammatory disease, and the inflammation in and of itself impacts patients’ quality of life by causing fatigue, let alone the numerous digestive symptoms that the patients may have, including diarrhea, abdominal pain, weight loss, fevers, and inflammation around the anal canal that can impact on sexual functioning and relationships. Really, Crohn’s disease has a global impact on quality of life.

When we are talking about the populations at risk for Crohn’s disease, we used to think that Crohn’s disease was primarily a Jewish disease. However, over the past decades, we’ve seen Crohn’s disease expand worldwide, and it no longer just affects Caucasian or Ashkenazi Jewish populations. We’re seeing an expansion of Crohn’s disease in Europe. And despite some evidence of genetic underpinnings in the West, those same genes are not the same in the East, as in Asia, where we’re seeing the populations expand. Of interest, it’s the same kind of populations in the United States. Crohn’s disease doesn’t occur in the villages. It occurs in the cities. So, as populations develop western lifestyles—and that includes many aspects of hygiene, diet, use of antibiotics, and cigarette smoking—we’re seeing it across all populations.

Transcript edited for clarity.