This Is How Doctors Diagnose Crohn’s Disease

The sooner you have a diagnosis, the sooner you can start treatment.

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An estimated 780,000 people in the United States live with Crohn’s Disease—an autoimmune disease that affects the digestive tract—according to the Crohn’s and Colitis Foundation. This gastrointestinal disease can have a major effect on quality of life, not to mention it comes with a risk of complications if it goes untreated. 

Before starting treatment, of course, you need a diagnosis. Getting a diagnosis can help you and your doctor determine whether you have Crohn’s, what type of Crohn’s you have, and what the best treatment plan for you might be.

How Crohn’s Disease Affects the Body

Like other autoimmune diseases, Crohn’s disease means the immune system is attacking your own body—in this case, the digestive tract.  

For people without Crohn’s disease, the digestive tract “works in a state of tolerance, so lots of things pass through [the] bowel, and it doesn't react to those triggers that are coming through,” says Benjamin Cohen, MD, gastroenterologist at The Mount Sinai Hospital. 

“In a patient with Crohn's disease, the immune system will recognize those triggers as foreign, when maybe they shouldn't, and that can lead to an immune response, attacking the gut itself,” says Dr. Cohen. Even once the trigger passes out of the system, the immune response continues, leading to symptoms of Crohn’s disease, such as abdominal pain and diarrhea.

Steps to Diagnose Crohn’s Disease

To diagnose Crohn’s disease, doctors will typically begin by asking you about your medical history and family history. Then, your doctor will likely perform a physical exam—checking for abdominal bloating, listening to your stomach with a stethoscope, and tapping on your abdomen to check for pain or enlarged organs.

Next, your doctor may perform lab tests. “Crohn's disease is diagnosed through colonoscopy, generally,” says Dr. Cohen. “You can identify the inflammatory changes in the bowel and find typical features on biopsies that are consistent with Crohn's disease.”

A colonoscopy only examines the large intestine, which is commonly affected by Crohn’s disease. However, inflammation in the large intestine could also indicate ulcerative colitis. In many cases, you may also need an upper endoscopy, which helps examine the upper intestinal tract, or a CT scan, which can help your doctor see the structure of your digestive tract. 

In some cases, your doctor may also want to take blood tests or stool tests, which can help confirm the presence of inflammation, or to rule out other potential diseases. 

“Once we know what type of Crohn's that patient has, then we discuss what are the possible treatment options, and that's where it's important for a patient to be part of that discussion,” says David P. Hudesman, MD, associate professor in the Department of Medicine and medical director of the IBD Center at NYU Langone Health.

“With proper treatment for Crohn's, appropriate follow-up, the vast majority of people do very well with a great quality of life,” says Dr. Hudesman, “and there's no reason why that can't happen for any of our patients, as long as they're following up regularly and discussing their care with their physicians.”