INFLAMMATORY BOWEL DISEASE

Inflammatory bowel disease (IBD) can be divided into two chronic inflammatory disorders of the gastro-intestinal tract, Crohn’s disease and ulcerative colitis. Crohn’s disease can affect any part of the gastro-intestinal tract, whereas ulcerative

Colitis affects only the large intestine. IBD follows a relapsing and remitting course that is unpredictable and causes disruption to a patient’s lifestyle and places a burden on the workplace and healthcare setting. The management of IBD patients raise a challenge to the multidisciplinary team both clinically and economically.

AETIOLOGY

 The precise causes of IBD is unclear, although its development and progression are multifactorial.

ENVIRONMENTAL

• DIET

Evidence that dietary intake is included in IBD is inconclusive. Some dietary factors have been associated with IBD, including fat intake, fast-food ingestion, milk and fiber consumption and total protein and energy intake.

• Smoking

There is a higher rate of smoking amongst patients with Crohn’s disease than in the general population, with up to 40% of patients with the disease being smokers. Smoking worsens the clinical course of the disease and increases the risk of relapse and the need for surgery. 

• Infection

Exposure to Mycobacterium paratuberculosis has been considered a causative agent of Crohn’s disease, although current evidence indicates it is not a causative factor.

• Enteric microflora

Enteric microflora plays an important role in the pathogenesis of IBD because the gut acts as a sensitizing organ that contributes to the systemic immune response.

• Drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) such as diclofenac have been reported to exacerbate IBD. Antibiotics may also precipitate a relapse in disease due to a change in the enteric microflora.

• Appendicectomy

Appendicectomy has an inverted association with Crohn’s disease and ulcerative colitis. For ulcerative colitis, it is protective against disease development, whereas appendicectomy for appendicitis appears to increase risks of Crohn’s disease.

• Stress

Some patients find that stress triggers a relapse in their IBD.

Genetic

A general predisposition to IBD is well established. Jews are more prone to IBD than non-Jews, with Ashkenazi Jews having a higher risk than Sephardic Jews. In North America, IBD is more common in whites than blacks.

Pathophysiology

In individuals with IBD, trigger factors typically cause a severe, prolonged and inappropriate inflammatory response in the gastro intestinal tract, and the inflammatory reaction leads to an alteration in the normal architecture of the digestive tract.

Clinical Features

Crohn’s disease

Crohn’s disease can affect any part of the gut from the mouth to the anus. Crohn’s disease can involve one area of the gut or multiple areas, with unaffected areas in between being known as ‘skip lesions’. The clinical features of Crohn’s disease depend in part on the site of the bowel affected, the extent, severity and the pathological process in each patient.

Crohn’s disease tends to be more disabling than ulcerative colitis, with 25% of patients unable to work 1 year after diagnosis. The predominant symptoms in Crohn’s disease are diarrhea (which may contain some blood and mucus), abdominal pain and weight loss.

Weight loss occurs in most patients, irrespective of disease location. Ten to twenty percent of patients will have weight loss greater than 20%. The main cause is decreased oral intake, although malnutrition is also common. As a result, patients sometimes have a low body mass index (BMI). Growth retardation is common in young Crohn’s patients.

Ulcerative colitis

Typical symptoms of ulcerative colitis include bloody diarrhea (the most predominant symptom) with mucus, urgency and frequency. Abdominal pain usually is of cramps associated with (and relieved by) the urge to defecate. Weight loss occurs in severe cases. Frank blood loss is more common in ulcerative colitis than Crohn’s disease. Approximately 50% of patients with ulcerative colitis have some form of relapse each year and severe attacks can be life-threatening.

Investigations

A full patient history should include recent travel, medication (such as recent use of antibiotics or NSAIDs), sexual and vaccination history as appropriate and identifying potential risk factors such as smoking, family history and recent infection, such as gastroenteritis.

Endoscopy

The key diagnostic investigation in IBD is lower gastro-intestinal tract endoscopy (sigmoidoscopy and colonoscopy).

Radiology

Radiological imaging is used in the initial evaluation or diagnosis, preoperative review, to highlight the presence of complications during exacerbations and to evaluate extra-intestinal manifestations.

Laboratory findings

Although not diagnostic, active disease is suggested in patients with raised inflammatory markers that include erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP).

Stool tests

Stool tests do not diagnose IBD but contribute to excluding alternative diagnoses, such as infection and identifying a potential precipitant for a flare in symptoms.

Clinical assessment tools

Treatment

At present there is no cure for IBD because the exact cause of the condition is unknown. Widely ranging drugs and nutritional supplements are available to maintain the patient in long periods of remission in both Crohn’s disease and ulcerative colitis. However, surgical intervention often becomes necessary if a complication occurs or if the patient fails to respond to medical therapy.

Nutritional therapy

Nutritional therapy can be considered as primary treatment. Although a potential problem for all patients with IBD, patients with Crohn’s disease are at particular risk of becoming malnourished and developing a variety of nutritional deficiencies.

 nutritions include fruits, vegetables, whole grains, lean protein, and low-fat and nonfat dairy products but in case of malnutrition total parenteral nutrition(TPN) may be prescribed.

Drug therapy

Drug treatments are often required for many years, and patient preference, acceptability and potential side effects affect both choice and potential medication adherence.

 The mainstays of drugs used in the treatment of IBD are corticosteroids(prednisole), aminosalicylates(sulfasalazine), immunomodulators(azathioprine) and biologics(infliximab).