Many people are confused when it comes to the differences between inflammatory bowel disease (IBD), Crohn's disease (CD), and ulcerative colitis (UC). The short explanation is that IBD is the umbrella term for the condition under which both Crohn's disease and ulcerative colitis fall. But there is, of course, much more to the story.
Although both CD and UC are marked by an abnormal response by the body’s immune system and may share some symptoms, there are important differences as well. Heterogeneousness features include the location of the maladies in the gastrointestinal (GI) tract and the way each disease responds to treatment.
A Brief History of Inflammatory Bowel Disease (IBD)
Inflammatory bowel disease is usually only used to refer to CD or UC; however, a few other diseases may be referred to as IBDs as well. These include microscopic colitis, diverticulosis-associated colitis and Behçet's disease.
IBD was seldom seen before the rise of improved hygiene and urbanization at the beginning of the 20th century and today, it’s still found mainly in developed countries such as the United States. Like other autoimmune and allergic disorders, it’s believed that a lack of germ resistance development has led to diseases such as IBD.
In people with IBD, the immune system mistakes food, bacteria, or other materials in the GI tract for foreign substances and responds by sending white blood cells into the lining of the bowels. The result of the immune system's attacks is chronic inflammation. (The word inflammation itself comes from the Greek word for flame. It literally means "to be set on fire.")
Inflammatory bowel disease may strike at any age, but usually shows up first in people between the ages of 15 and 35. It appears most often in temperate climates such as in North America, the UK, Scandinavia, and other Western European countries. It’s more common: in urban areas than rural ones; among people in higher socio-economic brackets than poorer ones; and Caucasians as opposed to darker-skinned people and those of Asian descent.
A U.S. study of 9 million people found that Crohn's disease is present in an average of 201 per 100,000 Americans, while ulcerative colitis is found in 238 per 100,000. The numbers were comparable—although slightly lower—among Canadians, and lower still in Europe. Recent studies have also shown that IBD is on the rise among children less than nine years old.
Aside from environmental factors, genetic factors are believed to play a strong role in the development of IBD. Therefore, it’s considered a "complex disorder."
Unfortunately, there’s currently no cure for IBD. People with inflammatory bowel disease can expect to live with the disease for their entire lives, with alternating periods of remission and flare-ups. Modern treatments, however, allow people to live relatively normal and productive lives.
Also, IBD should not be confused with irritable bowel syndrome, or IBS, which is sometimes referred to as either "nervous colitis" or "spastic colon." IBS is a much less serious affliction than either Crohn’s disease or ulcerative colitis. It doesn’t involve inflammation or appear to have a physiological basis.
Crohn’s disease may affect any part of the GI tract from the mouth to the anus, although it’s most often found at the end of the small intestine (small bowel) and the beginning of the colon (large bowel).
Symptoms of Crohn's disease include persistent diarrhea, crampy abdominal pain, fever, occasional rectal bleeding, and fatigue. Unlike with UC, Crohn's isn't limited to the GI tract and may also affect the skin, eyes, joints, and liver. Because symptoms usually get worse after a meal, patients with Crohn's will often experience weight loss due to food avoidance.
Complications of Crohn's disease are blockages of the intestine due to scarring and swelling, and ulcers (sores) in the intestinal tract which may develop into tracts of their own, known as fistulas. For up to 30 percent of Crohn's sufferers, these fistulas will become infected.
Medication is the most common way to treat Crohn's disease. However, between two-thirds and three-quarters of patients will eventually require surgery. The five types of drugs that treat CD are: steroids, antibiotics, immune modifiers such as azathioprine and 6-MP, aminosalicylates such as 5-ASA, and biologic therapy.
Unlike Crohn's, ulcerative colitis is confined to the colon (large bowel) and only affects the top layers in an even distribution. Symptoms of UC include crampy abdominal pain, loose, bloody stool, and urgent bowel. Other side effects may include fatigue, loss of appetite, and in severe cases, anemia due to blood loss.
Children with the disease may not develop or grow properly. About half of UC patients will have mild symptoms, with some experiencing no distress at all. Remission periods tend to be longer with UC than with Crohn's disease and complications are far less frequent. With the exception of biologic therapy, treatments for the disease are the same as for Crohn's. Unlike with Crohn's, however, most patients with UC will almost never require surgery.