What is Crohn's Disease?

About half of the cases of Inflammatory Bowel Disease in Canada are Crohn’s disease, and the number of people being diagnosed with it each year does not appear to be changing. Crohn’s disease is inflammation in the bowel caused by the immune system, an autoimmune disease. It can affect all of the layers of the intestinal lining, potentially leading to deep ulcers.

Crohn’s disease can be categorized in two ways: the first is based on where the disease activity is (location) and the second is what the disease does (phenotype).

Location

Crohn’s disease can affect any part of the gastrointestinal tract from the mouth to the anus.

Terminal ileum and colon
Perianal involvement
Mouth/upper GI tract

Phenotype

Crohn’s disease behaves differently in different people, but there a few common patterns of disease activity each with their own set of complications to be aware of.

Inflammatory CD
Stricturing CD
Fistulizing/Penetrating CD

Causes

Researchers have been studying the causes of Crohn’s disease for many years in hopes of finding a cure. Scientists have confirmed genetic and microbiome differences, as well as the role of smoking. Antibiotics and lifestyle factors may also contribute but are difficult to study. Currently, it is thought that there are multiple interacting factors that likely contribute to the onset of the disease.

Genetics

In Crohn’s Disease, the immune system attacks the GI tract, so everything that impacts the immune system could contribute to the cause of this disease ...

Keep reading

Smoking

Smoking alters the immune system and is a known cause of Crohn’s disease. Smoking also worsens the severity of Crohn’s disease in people who already suffer from it ...

Keep reading

Microbiome

An abundance of bacteria live in the last part of the GI tract and help provide us with nutrients, digest certain foods, and modulate our immune systems ...

Keep reading

Signs & Symptoms

Crohn’s disease is a chronic, inflammatory disease that can affect multiple parts of the digestive tract. Depending on the area that is inflamed, the symptoms vary, but common symptoms include:

  • Abdominal pain
  • Diarrhea
  • Weight loss
  • Fever
  • Fatigue
  • Bloody stool
  • Perianal pain, swelling or drainage
  • Oral ulcers
  • Extra-intestinal (outside of the abdomen) symptoms: joint pains, rashes, eye inflammation, blood clots

In some, the disease is ‘relapsing-remitting’ (coming and going), and in others, it is persistent without effective treatment.

Extra-intestinal Manifestations

Sometimes Crohn’s disease manifests itself outside the intestines with the following conditions:

Primary sclerosing cholangitis (PSC)
Erythema nodosum
Pyoderma gangrenosum
Eye inflammation (uveitis, iritis, episcleritis)
Thrombosis
Arthropathy and arthritis

Diagnosis

There are a number of steps in the diagnosis of Crohn’s disease.

  1. History

    Your gastroenterologist will ask you key questions about your symptoms in a confidential manner.

  2. Physical Examination

    Your gastroenterologist will conduct a physical examination which looks at the whole body as well as the abdomen.

  3. Laboratory Testing

    Blood tests and stool tests are an important step in diagnosing Crohn’s disease and to make sure no complications have developed.

    Learn more

  4. Imaging and biopsies

    To diagnose Crohn’s disease, a camera test (colonoscopy i.e. endoscopy) needs to be performed to assess disease activity and to obtain biopsies (small pieces of tissue) which can confirm the diagnosis. Occasionally other imaging tests need to be done; these may include ultrasound, CT scans, or MRI.

    Learn more

Medical Treatment

Unfortunately, Crohn’s disease does not yet have a cure. The goal of treatment is ‘complete remission’, meaning a return to normal bowel function and a resolution of inflammation on blood work and camera testing. Ideally, remission is maintained in the long term by avoiding any flares or relapses. Ultimately, the goal is to allow people to live full lives and to stop Crohn’s disease from holding anyone back.

Everyone will have a different experience with Crohn’s disease and will require an individualized approach to treatment. Below is a very brief overview of some of the common types of medications used to control Crohn’s disease.

Medical treatments for Crohn’s disease

5-Aminosalicylic Acid (5-ASA)

Anti-inflammatory medications that work on the lining of the colon.

Immunomodulators (methotrexate, azathioprine)

These alter immune function to prevent flares.

Corticosteroids (prednisone, budesonide)

These suppress the immune system and are most commonly used during flare ups.

Biologics

These are bioengineered proteins that block specific signals that drive intestinal inflammation. They require special testing before use and strict adherence to injections or infusions. The term ‘biologic’ is a generic term -- each biologic is different. Usually administered once every 4-8 weeks.

Some treatments for IBD modulate the immune system to help reduce inflammation in the GI tract. A side effect of modulating the immune system is that it can increase susceptibility to infections. It is recommended to have up-to-date vaccinations before starting certain IBD treatments. The following vaccinations are recommended for everyone with IBD, and your doctor may suggest additional ones that not everyone in the general public will receive.

One time only:
HPV, Shingles, Hepatitis A and B vaccines

Annual:
Influenza injection (no nasal spray)

Every five years:
Pneumonia vaccine, limited to a few doses

Every ten years:
Tetanus vaccine

Surgical Treatment

Occasionally, complications of Crohn’s disease can occur that require surgical treatment. Over time, chronic inflammation of the digestive tract can lead to scarring. This can then lead to narrowing called a stricture that can cause an obstruction. Another potential complication of chronic inflammation is the formation of a fistula (connections between the bowel and surrounding structures). Both of these complications can sometimes require surgery. Finally, people with IBD are at higher risk for colon cancer (which can require a surgery) because of chronic inflammation causing damage. We try to prevent people from ever needing surgery but those who require surgery usually do very well after an operation.

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