Inflammatory bowel disease (IBD) refers to two chronic inflammatory conditions of the GI tract, Crohn’s disease (CD) and Ulcerative colitis (UC). The prevalence of Ulcerative colitis is about 230 per 100,000 population and the prevalence of Crohn’s disease is about 200 per 100,000 population. The age of onset of both Crohn’s disease and Ulcerative colitis is typically between 15 and 40. It is believed that inflammatory bowel disease occurs when the immune system of a genetically susceptible person becomes intolerant of and reacts abnormally to the normal bacteria that populate the gut. Ten to 25% of people affected with IBD have a first degree relative who is also affected. Aside from genetics, risk factors for developing IBD include smoking (in case of Crohn’s disease but not Ulcerative colitis), and other environmental triggers, such as a history of infectious gastroenteritis and psychological stress, although the last two have not been uniformly confirmed.
Typical clinical presentations
Crohn’s disease may involve any part of the GI tract and usually presents with persistent abdominal pain and diarrhea, sometimes associated with weight loss and fevers. Rectal bleeding may also occur.
Sites of Crohn’s disease involvement
Green – Colon
Red – Ileum and colon
Symptoms will depend on the site of disease involvement. Small bowel disease may cause nausea, vomiting, abdominal pain and weight loss. Large bowel disease more commonly causes diarrhea and bleeding, although abdominal pain, weight loss and fevers may also occur. Crohn’s disease is characterized by “skip lesions”, where areas of disease are interspersed between areas of healthy bowel.
Ulcerative colitis only affects the large intestine. The inflammation in Ulcerative colitis starts in the rectum and moves up. Inflammation in Ulcerative colitis is continuous. The disease may affect only the rectum (ulcerative proctitis), the rectum and the sigmoid colon (proctosigmoiditis), the left side of the colon (left-sided colitis) or the colon as a whole (pancolitis). Ulcerative colitis usually presents with diarrhea, rectal bleeding, an urgency to defecate, and a sense of incomplete evacuation. Weight loss and fevers are rare unless the disease is severe.
Similar symptoms may be associated with other conditions, such as infections of the GI tract, poor blood supply to the GI tract, dietary intolerances (as occurs with gluten or lactose intolerance), irritable bowel syndrome (IBS), hemorrhoids and anal fissures. Inflammatory bowel disease is diagnosed based on the typical endoscopic and microscopic findings.
IBD is a chronic condition with a variable course. In some people the disease runs a mild course with very infrequent symptoms. In other people periods of disease control may be interrupted by disease flares. The frequency and severity of disease flares dictate the choice of therapy. The choice of therapy takes into account the patient’s age, co-morbidities, life style choices, reproductive goals and ultimately requires an ongoing discussion between the patient and the doctor.