How common are Crohn’s disease and ulcerative colitis?

The highest worldwide incidence and prevalence of Crohn’s disease reported to date is in Canada. There are geographical and racial variations in the occurrence of both diseases for reasons that are not clear. About one in 350 Canadians suffer with inflammatory bowel disease, with females forming a slightly higher portion of Crohn’s patients than males.


Are these diseases infectious?

Although the cause of IBD is unknown, and physicians sometimes prescribe antibiotics as treatment, researchers have never been able to identify definitively any infecting bacterium, virus, fungus, or parasite. However, physicians believe that Crohn’s disease and ulcerative colitis cannot be ‘caught’ or ‘given’.


Are these diseases inherited?

Based on current information, IBD is not hereditary in the classical definition of a hereditary disease; therefore, there is no predictability that a child of an affected parent will develop the disease. However, there is an increased risk for those who have a family member with IBD, as 20% of persons with Crohn’s have a parent, sibling, or child with the disease. If your sibling has Crohn’s, then you have a 30% higher likelihood of developing Crohn’s compared to the general population. There is also a higher risk of developing ulcerative colitis for those with a relative who already has this disease.

Prior to 2007, there were only three known genetic risk factors for Crohn’s disease, but an extensive breakthrough study by an international consortium of Crohn’s disease researchers in 2008 offered more insight into the genetic indications for Crohn’s disease. By comparing the genomes of patients with Crohn’s disease to those of healthy individuals, researchers confirmed 11 genetic markers identified in 2007 and identified 21 new ones. Recent research has also identified some genes that appear to provide protection against developing IBD, but scientists are still investigating the implications of these findings. These new discoveries continue to build a picture of factors leading to the inappropriate immune-system activation that characterizes inflammatory bowel disease.


Do these diseases occur often in children and how does the course differ from that in adults?

IBD is very commonly first diagnosed in individuals between the ages of 15 and 25, but about 10% are diagnosed at a younger age and some might not be diagnosed until much later in life. Unfortunately, the outlook is worse for patients diagnosed at a younger age because delayed growth may occur if the onset of disease is before puberty, as nutrient absorption can be severely impaired. Additionally, the complication rate in children is higher and having the disease for a longer period means that more surgeries are likely.


Is anything known about possible causes?

The cause or causes are undetermined at present. There is considerable evidence to suggest that in some persons with these diseases, allergic-like reactions (antigen-antibody) occur in the tissues of the intestinal tract. This means that the body’s defence mechanisms are operating against some materials in the digestive tract that they recognize as foreign matter. Exactly what initiates this reaction in the body (e.g. viruses, bacteria, food substances or other kinds of toxic agents) remains a mystery. What starts out as a defence mechanism may then become the disease.

A source of debate for many years has been whether Crohn’s disease and ulcerative colitis have the same cause. Some contend that the cause is the same and that different types of inflammation are due to the different locations of the disease process. Others contend that they are two unrelated disease processes and share only the fact that they involve intestinal tissue. More research is required to clarify this important question.


Are these autoimmune diseases?

The term autoimmune disease refers to any one of many conditions where the body’s defence mechanisms appear to be attacking its own tissues. Some features of both Crohn’s and colitis that resemble an autoimmune reaction, including:

  • the young age of patients affected
  • pathological changes in the intestinal tissues,
  • the associated complications that sometimes involve the skin, joints or eyes,
  • abnormalities that may occur in various blood tests, and
  • the favourable response to certain “anti-allergic” drugs such as cortisone.

We must emphasize, however, that these so-called autoimmune features are really quite non-specific. The same features may occur in a wide variety of inflammatory diseases, infections, and other conditions. To refer to Crohn’s disease and ulcerative colitis as autoimmune should in no way imply that the underlying causes of these diseases are known or understood.


Can psychotherapy cure or at least help control these diseases?

Since no one knows the causes of these diseases, no one can say for sure what role psychological factors play. While physicians today believe that emotional problems or stress do not cause Crohn’s disease or ulcerative colitis, most would also agree that these factors may influence the course of the disease – just as they influence the course of many other chronic diseases.

The clinical course of these diseases can be so varied and unpredictable that it is not possible to make any categorical statement about whether psychotherapy does or does not help. Some patients seem to benefit from psychiatric treatment while others do not. Perhaps a general rule to adopt is that if patients have emotional problems, which seem to be affecting their health or otherwise disturbing their lives, then psychiatric treatment may help. If successful, the course of the Crohn’s disease or ulcerative colitis may often simultaneously improve. However, in no case should any patient receiving psychotherapy cease or be deprived of medical care!


What effect do Crohn’s disease and ulcerative colitis have on pregnancy and conception?

The fertility rates for women who have Crohn’s disease or ulcerative colitis vary. If Crohn’s disease is active, then fertility drops slightly. For IBD patients, the rate of spontaneous abortion rises to 13%, which is approximately double that of the average population, while the chances of having a normal child are no different. In some patients, the illness worsens during pregnancy, while in others it might remain unchanged or even improve. Some medications are counter-indicated and it is critical that patients consult their physicians when considering pregnancy.


What are fistulae?

These are abnormal passageways between the inflamed intestinal tissue and some adjoining tissue or another segment of intestine. These sinus wound tracts are characteristic of Crohn’s disease, particularly when connecting two segments of intestine or burrowing from the ileum to areas within the abdominal cavity. Complicated fistulae occur around the anus and rectum in Crohn’s disease. Fistulae are not characteristic of ulcerative colitis, although they occasionally occur in the rectal region or between the rectum and vagina.


Do people with Crohn’s disease and ulcerative colitis develop cancer?

Cancer of the small intestine, where Crohn’s disease usually occurs, is an exceedingly rare disease. However, after many years of involvement with Crohn’s disease, the incidence of cancer in the small intestine may be slightly higher than in the average population.

More is known about the potential risk of cancer of the large intestine, or colon, as a complication of ulcerative colitis or Crohn’s disease. The incidence is significantly greater than in the average population but usually occurs when the entire colon has been involved for at least 10 years, after which incidence continues to rise slowly. Patients in this situation should have more vigilant screening for colon cancer than recommended for the general population.


What are the long-term effects of steroids?

Side effects of steroids include reversible cosmetic ones such as fluid retention, facial fullness, easy bruising, and acne. More serious but significantly less common ones are peptic ulcers, high blood pressure, psychiatric disturbance, osteoporosis, cataracts, and avascular necrosis of the joints. The vast majority of these complications improve or resolve with the reduction or elimination of steroid treatment. Furthermore, these side effects usually occur only with prolonged high-dosage use.


What is an ostomy?

When removing portions of the bowel due to disease activity, a surgeon might need to create a new route for elimination of body wastes. Cutting across the abdominal wall, a surgeon removes the damaged intestine, draws the disease-free portion through to the outside of the body, and then sews this to the skin. A number of products are available for fitting around this hole to collect the body’s waste material. The cut end of the small intestine (ileum) protruding out of the hole (stoma) in the abdominal wall is an ileostomy, while the large intestine (colon) surgically altered in this way is a colostomy. Ileostomies and colostomies could be either temporary or permanent, depending upon the individual case.


Why perform surgery for Crohn’s disease if it does not prevent it spreading?

Sometimes complications of Crohn’s disease, such as an obstruction, extreme narrowing of the bowel, abscess formation, or fistulae warrant surgical correction – often urgently. If new disease does occur later, it is typically easier to treat than the original involvement.


Can I prevent Crohn’s disease?

Researchers are now conducting controlled experiments with those drugs known to have any effect at all against inflammation, to measure their success in Crohn’s disease. Regrettably, so far no preventative medication is available.


Even though there is no cure, what can patients with these diseases hope for with present-day treatment?

It is important to remember that many patients, in whom the disease is under control, can be relatively symptom-free, and lead essentially normal lives. Very few succumb directly to the disease. Many patients have mild symptoms much of the time and severe symptoms for shorter periods. Patients might have surgery and then may be totally or nearly well for many decades. Thus, these diseases behave somewhat as do other chronic diseases such as arthritis or some chronic skin disorders for which we also have no definite curative treatment.

The principal drugs in use today are far better than those that were available 20 years ago. One can hope that the newer and more experimental treatments presently under careful study will lead to a better understanding of IBD.


What about intestinal transplant?

This is a relatively experimental procedure, where surgeons transplant the entire intestinal tract. Regrettably, Crohn’s disease seems to appear in the newly transplanted bowel within a few months. These results have given scientists a better understanding of the disease, which may lead to further research into the cause and mechanism of Crohn’s disease.