Inflammatory Bowel Disease

Small Bowel Conditions
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Inflammatory bowel disease is an umbrella term used to define two conditions affecting the gastrointestinal tract, Crohn’s disease and ulcerative colitis. Both of these conditions are life long, with patients requiring specialist input.

The different mucosal changes seen in inflammatory bowel disease (Crohn’s disease and Ulcerative colitis) in comparison to a healthy bowel
Inflammatory bowel disease is an umbrella term used to define two conditions affecting the gastrointestinal tract, Crohn’s disease and ulcerative colitis

Crohn’s Disease

Crohn’s disease is an autoimmune condition that can affect any part of the gastrointestinal tract starting from the mouth and ending at the anus. It occurs as ‘skip lesions’ which is different to ulcerative colitis which is a continuous part of the affected bowel. Although the underlying cause behind Crohn’s disease is unknown genetics, environment and bacterial colonisation play a role. Crohn’s disease can develop following a bout of food poisoning (gastroenteritis). Studies have also shown that smoking can trigger/worsen the condition, therefore smoking cessation is advised.

The three most common sites of intestinal involvement in Crohn’s disease are the Ileocolic, Ileum and Colic
Different disease patterns seen in Crohn's disease of which the ileocolic (where the small bowel connects to the large bowel) is the most prevalent

Ulcerative colitis

Ulcerative colitis is a condition that predominately affects the large bowel, usually in a continuous fashion. This condition involves inflammation and ulceration of the lining of the large bowel, usually starting from the rectum and spreading up along the large bowel in a continuous fashion. It can occasionally enter the last part of the small bowel (backwash ileitis). The current understanding of this condition is that it is an autoimmune condition, meaning that the body’s own immune system is targeting its own healthy tissue, with a mix of genetic and environmental factors having an influence of this condition.

The common sites of large bowel involvement in Ulcerative Colitis and its presenting features
Common symptoms and types of Ulcerative Colitis

 

 

Symptoms of inflammatory bowel disease

Symptoms of inflammatory bowel disease
Common symptoms of inflammatory bowel disease include change in bowel habits and abdominal pain

Crohn’s disease typically occurs in childhood and early adulthood, and patients often experience crampy abdominal pain, blood in the stool (PR bleeding) and prolonged periods of diarrhoea (more than 7 days), weight loss and if there is an infection then fever can be present. Patients can also develop fistulas which are an abnormal connection between two surfaces. Crohn’s disease can also have manifesting signs outside of the gastrointestinal tract and include mouth ulcers, uveitis (eye pain with blurred vision), increased incidence of gallstones as the small bowel can be affected interfering with the reabsorption of bile acids, skin manifestations (pyoderma gangrenosum) and can affect the spine either in its entirety or at specific joints (sacroiliac joints).

Symptoms of Crohn’s disease
Crohns disease primarily affects the intestines however it has extra intestinal manifestations.

Ulcerative colitis can develop at any age; it is most frequently diagnosed between 15-30 years of age. Patients may experience abdominal pain, relapsing bouts of diarrhoea that can contain blood or mucus and increased frequency of bowel motion. Before diagnosis patient may also experience excessive fatigue due to the loss of iron from PR bleeding, loss of appetite and weight loss.

Patients with IBD will suffer bouts of acute inflammation termed flare ups, where symptoms become more frequent which can be interspersed by weeks to months. The severity of flare ups is graded on the frequency of bowel motions, presence of fever and amount of blood.

Diagnosis of inflammatory bowel disease

Diagnosis of IBD is based on a detailed history, clinical examination and investigation. Investigations can include abdominal x-ray in the acute setting as ulcerative colitis can result in a complication called megacolon, in which the bowel becomes dilated and is at risk of perforating, other investigations include CR/MRI of the abdomen. However the gold standard investigation for IBD is colonoscopy which allows for visualisation of the bowl and samples of bowl tissue to be taken to confirm histological diagnosis between the two conditions.

Contrast radiography of the large bowel showing common changes seen in Diverticulosis
Diverticulosis as it appears on an X-ray of the colon

IBD has been shown to increase an individual’s risk of developing colon cancer and as such patients are kept under surveillance to ensure that any cancer is picked up early to allow a higher chance of successful treatment, with colonoscopy.

Management of inflammatory bowel disease

Life style modifications include adequate hydration, diets high in fibre and fruit as well as smoking cessation in Crohn’s disease. Medical management of this condition involves the use of a combination of immunosuppressant’s, aminosalicylates and corticosteroids which have been revolutionary in terms of preventing the need for surgery. If there is a concomitant infection then antibiotics are used. However medical management is not curative as currently no cure is available.

However in severe ulcerative colitis emergency surgery may be needed. If surgery is indicated then typically the whole large bowel can be resected (Panproctocolectomy) and while healing occurs the small bowel is contented to a stoma bag (ileostomy) and then reconnected to the anus down the line as a second procedure.

Since ulcerative colitis affects a continues part of the bowel and predominately within the large bowel a Panproctocolectomy is curative, however in Crohn’s disease which can affect any segment of the GI tract surgery is not curative and only indicated in emergency such as bowel perforation, bowel obstruction, with the aim of surgery to remove the least amount of bowel possible.