Crohn’s disease

Crohn’s disease is a chronic inflammatory disease of the gastrointestinal (GI) tract. It is usually found in the small intestine and colon, but can occur anywhere in the GI tract from the mouth to the anus. The inflammation of Crohn’s disease involves the full thickness of the bowel wall. This is different than Ulcerative Colitis, which is confined to the just the inner lining of the colon. The source of the inflammation is unknown. 

Patients with Crohn’s disease tend to have one of 3 types of disease.

1. Inflammatory: This is active inflammation of the bowel wall that causes pain, bleeding and diarrhea.
2. Stricturing: This is scarring that occurs after repeated bouts of inflammation, which leads to strictures or narrowing that causes obstruction.
3. Penetrating or fistulizing: Because the inflammation in Crohn’s disease is full thickness, it can extend through the wall of the bowel. As a result, patients can develop abscesses or fistula, which communicate with another structure such as bowel, bladder or even the skin.

We do not know what causes Crohn’s disease. It appears to be a combination of environment, gastrointestinal and immune factors. It is currently believed that patients with Crohn’s disease have been exposed to environmental factors such as bacteria, allergens, foods or other toxins, and they have an underlying genetic predisposition to have a dysfuntional immune response. A patient’s immune cells begin to attack their own intestinal cells. The inflammatory response causes abdominal pain, diarrhea, blood in the stool, infections, fistulas and strictures. Several genes associated with increased risk of Crohn’s disease have been identified. Viruses such as Epstein-Barr and CMV, and bacteria such as Bacteroides, Clostridium and Klebsiella have been associated with Crohn’s disease.

We do not know exactly what causes Crohn’s disease and we do not know how to identify individuals that may be susceptible to developing it. It appears to be an interaction between environmental factors and a person’s immunologic response to those factors. It is not a disease that someone just picks up or can “catch” from someone else.

The most common symptoms associated with Crohn’s disease are abdominal pain and diarrhea. The pain can be constant or episodic (such as after meals or during the evening). The pain can be diffuse throughout the abdomen or localized to the area of inflammation. The diarrhea is also a result of the inflammation. Because the inflammation damages the lining of the bowel, there may also be blood in the stool. 

Pain, stool frequency and bleeding increase with worsening disease severity. Patients with long-standing Crohn’s disease are often able to distinguish symptoms associated with Crohn’s from other more common abdominal complaints. Other symptoms include appetite loss, bleeding from the rectum, weight loss, fever, joint pain, fatigue and sores around the anal area. Children with Crohn’s disease sometimes have delayed growth. 

This disease often has periods of worsening and of dormancy. As a result, symptoms can wax and wane. Even when the symptoms are dormant, the disease does not go away. Flare-ups can be short or long, mild or severe. Close communication with your physician can help you find the best treatment to manage the activity of your Crohn’s disease.

Crohn’s disease can occur anywhere along the GI tract, but there are also other sites that can be affected. The terminal ileum (the very end of the small intestine at the point where it joins the colon) is the most common site of involvement, occurring in around 50% of patients. The colon can be the only site of disease for about 20% of patients. Another 20% of patients can have both small intestinal and colonic disease. Around 10% of patients will have isolated anal disease, but it typically occurs along with disease at another site. 

Not all of Crohn’s disease affects the GI tract. It can involve the skin with such processes as erythema nodosum, pyoderma gangrenosum or mouth ulcers. It can also cause arthritis and inflammation of the eyes.

The diagnostic tools of choice are CT scans, MRIs and colonoscopies. These are used when a patient presents with persistent symptoms of Crohn’s disease, such as abdominal pain, diarrhea with or without bleeding, and unexplained weight loss. The imaging studies look for areas of the small bowel or colon that are inflamed or thickened. They can also diagnose associated abscesses or fistulas. A colonoscopy can directly inspect the lining of the colon and terminal ileum to identify areas of inflammation, ulceration or structuring. 

Crohn’s disease can be difficult to diagnose because the symptoms are similar to many other diseases and conditions. Other conditions that may have similar symptoms include ulcerative colitis, appendicitis, irritable bowel syndrome, diverticulitis, peptic ulcer disease, inflammation of the pancreas or gallbladder, cysts or tumors of the ovaries or fallopian tubes, pelvic inflammatory disease, intestinal cancer, and infections.

Crohn’s disease does appear to have a genetic basis. Several studies have indicated that a major risk factor for developing the disease is the presence of a family member with Crohn’s disease. As many as 40% of patients with Crohn’s disease will have an affected first degree relative (parent, sibling or child). However, the predisposition appears to be genetic susceptibility to have an abnormal or dysfunctional immune response to an environmental factor such as bacteria, virus or allergy. Without the presence of the environmental factor, patients are unlikely to develop Crohn’s disease.

In the United States, about 1 million people have either Crohn’s disease or ulcerative colitis.

Crohn’s disease progresses over time and there is no cure. The earlier Crohn’s is diagnosed, the better your chances of controlling the symptoms.

The mainstay of Crohn’s disease management is medication. 

Medical therapy has two goals: to control active disease and to keep disease from becoming active. For patients with active disease, the severity dictates the aggressiveness or intensity of the medical regimen. For mild disease, patients are often treated with 5-ASA based agents such as sulfasalazine. Patients will also be asked to modify their diets and lifestyle to increase physical activity and decrease smoking. 

For acute flares or severe disease, steroids are used to decrease the inflammation because they have quick action. As symptoms come under better control, other medications such as immunomodulators or biologic agents are used to further improve the inflammation. 

Surgery is reserved for when complication of the disease occurs. Indications for surgery include failure of medication to control the disease, obstruction from strictures, fistula that are symptomatic, perforation or persistent bleeding.

Crohn’s disease is not contagious. It is not the result of an infection and cannot be passed from one person to another.

Historically, the mortality associated with Crohn’s disease was a result of chronicity and associated complications of the disease. Malnutrition, bleeding and infection were the most common causes. Today, with improvements in diagnosis, nutrition, Crohn’s medication, antibiotics and surgery, it is very rare for someone to die from Crohn’s disease.

Washington University Colorectal can provide options and treatments for Crohn’s disease. Meet our specialists below. 

Kerri Ohman, MD

Paul Wise, MD

Steven Hunt, MD

Matthew Silviera, MD

Matthew Mutch, MD