Crohn's Disease Treatment Medications & Prevention

Crohn's disease is a poorly understood inflammatory condition affecting any part of the bowel from the mouth to the anus. It. is characterised by a localised area of granuloma formation, variable in extent and severity and over time.

It affects, in order of frequency, the terminal ileum, the ileum and colon, the colon alone, and the rest of the small bowel. It can be a chronic disease causing malabsorption and considerable morbidity over several years, or appear in a subacute form, with little upset prior to symptoms appearing and the patient becoming acutely ill. Fissures and fislulae can form through the bowel wall onto the skin surface or into the peritoneal cavity, and fibrosis of the bowel can lead to obstruction.

The underlying pathology of Crohn's disease is poorly understood. In many respects, it mimics tuberculosis, but no infectious agent has ever been proved.

Crohn's disease presenting in general practice is often difficult to diagnose. Patients may have abdominal symptoms over a prolonged period, often months. The patients are usually young (aged 20 to 30) and may be infrequent consulters.

Significant change in bowel habit, associated with weight loss and abdominal pain, with or without rectal bleeding in someone under 30 should alert you to the possibility of the diagnosis. Vague complaints of ill-health, such as tiredness, myalgia, joint pains, nausea and anorexia may often be present.
Crohn's disease Diagnosis

The diagnosis can often be made in general practice from the history of recurrent abdominal pain and bowel disturbance, with features of malabsorption. There may be a history of rectal bleeding or perianal fissures. Children will present with similar symptoms plus failure to thrive or poor growth, but it is rare below the age of 10.

If you suspect Crohn's disease, the history, examination and investigations detailed below should lead you to exclude other causes and lead to a referral for further investigation. Erythema nodosum, a painful nodular eruption on the shins, is associated with Crohn's disease and would make the diagnosis more likely.
QUESTIONS TO ASK About Crohn's disease

    * Patients should be specifically asked about their bowel habit, particularly bowel frequency, the presence or absence of slime in the motions, and about rectal bleeding.
    * Malignancy is rare in this usual presenting age group of 20-30 years; frequent foul-smelling, slimy stools with small amounts of blood is more likely to indicate inflammatory bowel disease than cancer.
    * Constipation should be specifically asked about. Patients with Crohn's disease rarely suffer from constipation, but those with irritable bowel syndrome do.
    * A family history of bowel cancer may be significant, particularly bowel cancer in relatives under 45. Despite the 2-week wait guidelines, a high index of suspicion should be maintained, looking for those with familial tendency.
    * A history of travel abroad should be sought to exclude infectious causes.
    * Patients should be asked about any change in weight, joint pains, mouth ulcers or skin rashes — all positive features.

Crohn's disease Examination

Examination should look for signs of recent weight loss, anaemia or jaundice. Particular note should be paid to enlargement of the liver, focal tenderness, particularly in the right iliac fossa, and any masses in the abdomen. A rectal examination is mandatory to exclude a rectal malignancy, and look for evidence of rectal inflammation (tenderness, and blood on the examining glove).
INVESTIGATIONS

Tests for full blood count, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), liver function tests, urea and electrolytes, vitamin B12 and folate should be arranged to look for evidence of malabsorption (iron deficiency anaemia, macrocytosis due to B12 deficiency, low serum albumin) and signs of inflammation, particularly a raised erythrocyte sedimentation rate or C-reactive protein. Liver function tests may be deranged, and the white cell count raised. Stool samples should be sent to the laboratory for microscopy and culture to exclude an infective cause.

Further investigation should be done by a gastroenterologist and may include CT scanning and ultrasound examination of the abdomen, barium studies and direct visualisation with endoscopy. Biopsy of affected mucosa will prove the diagnosis histologically. The differential diagnosis includes intraperitoneal tuberculosis, and often ulcerative colitis, if disease is confined to the colon (see box, p87).
MANAGEMENT PLAN

The management of Crohn's disease in general practice initially consists of making the diagnosis and referring to secondary care for confirmation. Analgesia is probably the best initial intervention, with codeine phosphate or co-codamol. A small amount of loperamide might be considered if diarrhoea is copious and frequent.

Urgent referral should be made if any masses are present or malignancy is suspected. The blood test results will help confirm the diagnosis and the need for further investigation or referral.

In many cases, the first presentation will not lead to a diagnosis, because it is only after a period of time with repeated attacks that the cause can become clear. Careful record-keeping to show thoroughness in investigation and examination may save medico-legal consequences if a patient is undiagnosed for months or years.

Explanation of the disease to the patient and support are vital (see box below), along with advice about lifestyle and diet. Much of this aspect of management is now undertaken by specialist nurse practitioners in gastroenterology units.

Initial treatment of Crohn's disease aims to reduce the inflammation and makes use of oral corticosteroids, often in high doses. In acutely ill patients, intravenous steroids in hospital may be required. Antibiotics are worth considering, particularly if there is skin inflammation. Sulfasalazine (Salazopyrin) and its related drugs often produce a good response. Azathioprine or methotrexate, to suppress the immune system, are often used as a steroid-sparing agent once the patient has settled. The newer immunomodulatory drugs such as infliximab (Remicade) appeared to have a use in severe or unresponsive Crohn's disease. NICE has produced guidance on the use of this expensive treatment (see box).

Surgical management of Crohn's disease should be confined to those patients who have failed to respond to an aggressive medical treatment or who have complications requiring surgery, such as bowel perforation and obstruction, abscess formation, or for the management of fistulae. In extensive disease, a total colectomy may be needed, or there may be a requirement to remove so much diseased small bowel that long-term intravenous feeding is the result.

The latest in our series looking at everyday problems and how to tackle them in the average slot time. This month: Crohn's disease.

"Careful record keeping to show throughness in investigation and examination may save medico-legal consequences if a patient is undiagnosed for months or years"
Differential diagnoses

    * Infectious diarrhoea
    * Malignancy of the large bowel
    * Coeliac disease and other causes of malabsorption
    * Peptic ulceration
    * Irritable bowel syndrome
    * Intraperitoneal tuberculosis
    * Ulcerative colitis

NICE guidance on infliximab

Infliximab (Remicade) is recommended for the treatment of patients with severe Crohn's disease who fulfil all three of the following criteria:

    * Patients who have severe active Crohn's disease. These patients will already be in very poor general health, with weight loss and sometimes fever, severe abdominal pain and usually frequent (four or more) diarrhoeal stools daily. They may or may not be developing new fistulae or have extra-intestinal manifestations of Crohn's.
    * Patients whose condition has proved to be refractory to treatment with immunomodulating drugs (such as azathioprine or 6-mercaptopurine, methotrexate) and corticosteroids, or who have been intolerant of, or experienced toxicity from, these treatments.
    * Patients for whom surgery is inappropriate (perhaps because of diffuse disease and/or a risk of short bowel syndrome).
    * Infliximab is not recommended for patients with fistulising Crohn's disease who do not have the other criteria for severe active Crohn's disease as detailed above.
    * Infliximab should be prescribed by a gastroenterologist experienced in the management of crohn's disease.

Last updated Jan 4/07