Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the bowels, mainly affecting the colon and often involving the neighboring parts of the gut. Although the exact cause of inflammatory bowel disease is unknown, it appears to be associated with a genetic defect on the mucosal lining of the bowels and/or its response to the normal intestinal flora (bowel bacteria). There are two major types of IBD – Crohn’s disease and ulcerative colitis – with the latter being more common. The colon and rectum, like the entire gastrointestinal tract, is lined with a mucosal epithelium simply referred to as the mucosa. In inflammatory bowel disease, this mucosal lining and often the deeper layers are severely inflamed, ulcerated and structurally damaged to varying degrees.
What is ulcerative colitis?
Ulcerative colitis (UC) is a type of inflammatory bowel disease that is isolated only to the colon and rectum characterized by mucosal and submucosal inflammation often with the formation of shallow ulcers. As one of the two major types of inflammatory bowel disorders, the other being Crohn’s disease, ulcerative colitis is marked by recurrent bouts of severe diarrhea which is often bloody.
Although ulcerative colitis is closely related to Crohn’s disease, it is restricted to the colon and rectum unlike with Crohn’s disease that can occur anywhere in the gut but is usually isolated to the terminal part of the small intestine (ileum) and colon. Another key difference is that ulcerative colitis is limited to the mucosa and submucosa of the bowel wall, whereas with Crohn’s disease the infiltration can extend through the entire wall (transmural).
Histopathology and Pictures
Ulcerative colitis always involves the rectum (proctitis) and then extends proximally into the colon, initially involving the sigmoid colon (proctosigmoiditis) and possibly the entire colon (pancolitis). Even though the inflammation does not extend to the ileum (small intestine) in pancolitis, there may be some ileal mucosal inflammation (backwash ileitis).
Inflammation in all affected parts is continuous and not occurring in isolated patches like the skip lesions of Crohn’s disease. Severe and persistent inflammation leads to the formation of shallow ulcers which have a broad base and isolated parts of the mucosa (‘islands’) that starts healing form pseudopolyps. The remaining inflamed tissue appears red and bloody. Persistent ulcerative colitis may lead to atrophy of the affected tissue and in pancolitis this can lead to shortening of the bowel.
Ulcerative colitis in sigmoid colon. Picture from Wikimedia Commons.
Pseudopolyps in the colon of a patient with ulcerative colitis. Picture from Wikimedia Commons.
Distortion of the normal mucosa and ulcers. Picture from Wikimedia Commons.
Causes of Ulcerative Colitis
As discussed under the pathophysiology of inflammatory bowel disease, ulcerative colitis is most likely due to a combination of factors which in most cases arises from a genetic predisposition. Simply these hypotheses state that the normal mucosal immune response, which is the mucosa’s way of protecting itself, is dysfunctional and inflammatory mediators triggered unnecessarily without any obvious threat. This may be further complicated by disturbances in the epithelial tight junction which allows substances to enter and exit the tissue spaces in an unregulated manner. Lastly, antibodies are produced against the normal intestinal flora (naturally-occurring bowel bacteria) which mediates an immune response against these commensal microorgansims.
Other predisposing factors which may contribute to ulcerative colitis although the exact pathogenesis is unclear includes :
- NSAIDs – non-steroidal anti-inflammatory drugs.
- Low levels of vitamins A and E.
- Cigarette smoking.
- Cow’s milk.
- Infectious gastroenteritis.
- Low levels of sulfate-reducing bacteria in the bowels.
- Use of certain drugs like isotretinoin and antibiotics.
Signs and Symptoms of Ulcerative Colitis
Symptoms are most pronounced during the active phases and completely absent or just a few mild symptoms may be present during the remission phase. The characteristic feature of ulcerative colitis is the bloody diarrhea with stringy mucus. This is usually only evident during acute attacks, although patients may report some mucus in the stool on an ongoing basis between attacks. The diarrhea during the flareup is typically severe and accompanied by lower abdominal pain and cramps that are temporarily eased by passing stool.
Patients report a continuous urge to defecate, even immediately after a bowel movement, and this is present to some degree even between attacks. Fever along with signs or peritonitis and sudden violent diarrhea is indicative of toxic colitis and requires immediate medical attention. Weight loss is usually not prominent in ulcerative colitis unlike with Crohn’s disease, however, it may occur with extensive colitis. Other features may include a lack of appetite, anemia and malaise.
Some of the clinical features are not isolated to the colon (extracolonic manifestations) and may include :
- Joint pains (arthralgia)
- Eye inflammation (uveitis)
- Bile duct inflammation (cholangitis)
- Skin rash (erythema nodosum)
- Mouth ulcers (aphthous stomatitis)
Diet in Ulcerative Colitis
No specific dietary modifications are recommended in the treatment of ulcerative colitis but it may help with reducing or at least limiting acute flareups. Ulcerative colitis patients are largely individualistic with regards to diet and the disease. Some may find that certain foods and drinks are clear triggers although this is not common to all patients. Other foods may serves as triggers on some occasions but does not have any effect at other times. In this regard, it is advisable for patients to keep a daily food diary and note foods and drinks that may be trigger factors. Elimination diets may be of some use in acute flareups but often patients are aware of the main trigger foods without the need for dietary experimentation. Despite dietary modification, there is no significant evidence to suggest that this will prolong the remission phase.
It is important to bear in mind that many ulcerative colitis have concurrent lactose intolerance and dairy should therefore be avoided. Some of the foods and drinks that have been reported to be irritants by many patients include :
- Caffeinated beverages like coffee and colas
- Alcoholic drinks
- Carbonated beverages, even non-caffeinated and non-alcoholic drinks
- Milk and dairy products
- Chilli, peppers and other spicy foods
- High fiber diets
- Nuts and peanut butter
- Refined sugar although many sweeteners may also be irritants.
- Sugar free gum, ice cream and sweets
- High sulfur foods including onions and garlic.
- Processed, preserved and ‘cured’ meats
- Dried grain legumes and therefore seeds and fruits
- Raw vegetables particularly crunchy vegetables