Crohn’s Disease

Crohn’s disease is a lifelong inflammatory bowel disease. Inflammation and ulceration develop in the digestive tract, most often in the lower small bowel and upper colon. Day to day that can mean cramping pain, persistent diarrhoea, tiredness and weight loss.

What Crohn’s disease is, and what it is not

Crohn’s is one of two main forms of inflammatory bowel disease. Crohn’s and Colitis Canada describes it as able to strike anywhere from mouth to anus, in patches, with healthy bowel between. Ulcerative colitis differs: one continuous stretch in the colon and rectum, involving only the inner lining.

It is also not caused by anything you ate or did. The cause is not known, and Crohn’s and Colitis Canada points to genetics, environment and the gut microbiome. Food affects how you feel day to day, but it did not start the disease.

Signs and symptoms

• Cramping abdominal pain, often low on the right side
• Diarrhoea lasting weeks, sometimes with sudden urgency
• Blood in the stool
• Weight loss, low appetite and persistent tiredness
• Fever during a flare, and mouth ulcers
• Aching joints, sore eyes or skin sores, since inflammation can appear outside the bowel

Crohn’s runs in flares and quieter stretches, and no two people are the same.

What raises the risk

Some risk factors cannot be changed:

• A family history of Crohn’s disease or ulcerative colitis
• Age, since most people are diagnosed before 30
• Living in Canada, which the 2023 national report ranks among the highest burdens in the world

Others can often be worked on, usually with support from a health care team:

• Changes in the gut microbiome, named alongside genetics and environment
• Environmental exposures, listed while the exact cause remains unknown
• Regular contact with a gastroenterology team, since untreated inflammation leads to narrowed bowel, fistulas and abscesses

How Crohn’s disease is diagnosed in Canada

There is no single test. A family doctor usually starts with your history, an examination, and blood and stool tests. The Canadian Digestive Health Foundation describes the faecal calprotectin stool test as a way to see whether there is inflammation in the bowel, which helps separate inflammatory bowel disease from irritable bowel syndrome. A gastroenterologist then confirms it with endoscopy and biopsies, usually a colonoscopy reaching the end of the small bowel, plus imaging for the parts an endoscope cannot reach.

Treatment and day-to-day management

There is no cure, so care aims to settle inflammation and prevent complications. A gastroenterology team may discuss:

• Aminosalicylates, also written as 5-ASA, and corticosteroids to settle a flare
• Immunomodulator medicines taken longer term to keep inflammation down
• Biologic medicines and biosimilars, given by injection or infusion, grouped by Crohn’s and Colitis Canada as biotherapies
• Newer oral small molecule medicines, including JAK inhibitors and S1P receptor modulators
• Exclusive enteral nutrition, a liquid diet used mainly in children, and antibiotics in some cases
• Surgery when medicines are not enough or a complication develops, sometimes including an ostomy

No two cases are alike. These are decisions for you and your own gastroenterology team.

When to talk to a doctor

• Severe abdominal pain with vomiting, a swollen abdomen and no bowel movements can mean a blockage. Go to an emergency department, and call 911 if the pain is severe or you cannot keep fluids down.
• Heavy bleeding from the rectum, or feeling faint or short of breath with bleeding, needs emergency assessment.
• Fever with worsening abdominal pain, or a tender lump near the anus, needs same day assessment.
• Diarrhoea lasting more than a few weeks, blood in the stool, or unexplained weight loss should be assessed.

Why clinical research matters for Crohn’s disease

There is no cure, and many people either never respond well to a given medicine or lose their response over time. The 2023 national report shows inflammatory bowel disease in children rising year after year while adult onset stays flat, and no one can yet explain that, or why Canadian rates are among the highest in the world. Studies are testing new biologic and small molecule targets, diet and microbiome approaches, intestinal ultrasound for monitoring, and ways to predict who will need surgery.

Taking part is voluntary. You give informed consent first, you can stop at any time without affecting your regular care, and no one can say in advance whether a study will help you personally.

Learn more from Canadian sources

• Crohn’s and Colitis Canada: about Crohn’s and colitis
• Impact of IBD in Canada report
• Canadian Digestive Health Foundation: Crohn’s disease
• Gastrointestinal Society