Crohn’s disease is a chronic, lifelong inflammatory bowel disease (IBD) that can affect any part of the gastrointestinal tract. The disease mainly affects the lower part of the small intestine and/or the colon. In many patients, inflammation also occurs around the anus. In a few patients, the stomach and the upper part of the small intestine are also affected.
Inflammation in the lining and in the wall of the intestines causes swelling and ulcers, leading to abdominal pain, diarrhea and rectal bleeding. As the inflammation progresses, abscesses (collections of pus) may form adjacent to the bowel, resulting in abdominal pain, fever and night sweats. Over time, the inflammation may also be replaced by scarring of the intestinal wall, diminishing the inner diameter of the intestine and causing obstruction (blockage).
Patients with Crohn’s disease of the colon are at higher risk of developing colon cancer and are therefore screened more often than the average person.
WHAT CAUSES CROHN’S DISEASE?
Great progress has been made in understanding the root causes of Crohn’s disease. The current scientific thinking is that the disease occurs in people who are genetically susceptible to the disease and are exposed to harmful environmental factors (certain foods, cigarette smoking, and non-steroidal anti-inflammatory drugs (NSAIDs)). The combination of genes and environmental factors triggers abnormal inflammation in the intestine. White blood cells, which normally function to protect against infection, accumulate in large number in the intestine and release toxic products that damage the intestine.
RISK FACTORS FOR CROHN’S DISEASE
Crohn’s disease is partly genetic. Approximately 20% of patients with Crohn’s disease have a close relative with Crohn’s disease or ulcerative colitis. If an individual has a parent or sibling with Crohn’s disease, his/her chance of developing Crohn’s disease increases 6-fold. If an individual has both a parent and a sibling with Crohn’s disease, his/her chance of developing Crohn’s disease increases 34-fold. Other definite risk factors include Ashkenazi Jewish ancestry, cigarette smoking and NSAID use.
SYMPTOMS OF CROHN’S DISEASE
Abdominal pain is the most common symptom of Crohn’s disease. As inflammation builds up, the intestine muscle develops spasms. The inflammation also affects pain nerve endings in the gut. In some patients, longstanding inflammation leads to scarring and obstruction of the intestinal. Other symptoms include the following:
- Rectal bleeding;
- Weight loss;
- Nausea and vomiting (for example with bowel obstruction);
- Abscesses around the anus;
- Inflammation affecting other organs, including the eyes, joints, liver and skin.
DIAGNOSING CROHN’S DISEASE
The gastroenterologist performs a thorough history and physical examination before conducting blood and stool tests, colonoscopy and imaging studies. Important tests include the following:
- Blood tests: to rule out anemia and assess nutrition and severity of inflammation
- Stool tests: to rule out infection
- Colonoscopy with biopsies: to determine the presence of the disease and rule out other conditions
- CT or MRI scans of the abdomen and pelvis: to image the small intestine and colon, and rule out abscess, obstruction and conditions other than Crohn’s disease
TREATMENT OF CROHN’S DISEASE
Currently no medical cure exists for Crohn’s disease. The disease is well controlled by medications in most patients. These medications are given long-term (so called maintenance therapy); if stopped, the inflammation and symptoms will recur. Available treatment options include:
- Anti-TNF drugs, i.e. drugs that block tumor necrosis factor (TNF);
- Natalizumab, which prevents white blood cells from traveling to the intestine;
- Surgery: if an individual’s symptoms are not reduced through medications, then surgery is performed. Operations include:
- Strictureplasty: widening a blocked or narrowed area in the intestine, without having to remove it.
- Resection: removing the diseased part of the small or large intestine.
- Colectomy: removing the large intestine.
Symptoms frequently recur a few years after surgery. To minimize the chance of disease recurrence, the gastroenterologist frequently prescribes medication(s) right after surgery.