Affecting as many as 50-100 people per 100,000, Crohn’s disease is an inflammatory bowel condition closely related to ulcerative colitis. Dr Paul Lambden explores symptoms of both illnesses as well as methods of diagnoses and modern day treatments
Crohn’s disease, also known as regional ileitis, is a type of inflammatory bowel disease. Although it can affect any part of the bowel it classically affects the ileum (small intestine). There are about 50-100 sufferers per 100,000 of the population and it is more common in Northern Europe than Southern Europe. It most commonly affects people in the third decade of their lives but there is a second smaller peak in people in their sixties. The disease is more likely to be severe if it starts at a younger age.
Abdominal pain is the characteristic and, usually, the initial symptom of Crohn’s disease, often accompanied by diarrhoea which may be bloody and typically of large volume and watery. In severe cases the patient may suffer 15-20 bowel movements a day and have to get up at night. Blood is more common if the disease also affects the colon, which occurs in about 20% of patients. Other features depend on the sites affected by the disease and its severity and may include vomiting, dyspepsia, mouth ulcers, a constant feeling of wanting the bowels open and soreness and irritation round the back passage. More general symptoms may be malaise, weight loss, anaemia, a persistent low-grade fever, headache and depression. In some people joints are affected, producing an inflammatory arthritis which may affect the hips, knees and small joints of the hands and feet. Sometimes there are inflammatory changes in the eyes and red discoid patches may also appear on the skin.
The small bowel changes (ileitis) result in inflammation with scarring and the development of fibrous bands which encircle the intestine and lead to obstruction in many cases.
The cause of the disease is unclear but it is known to be associated with genetic factors and is more common in higher socio-economic groups. Other factors are the use of non-steroidal drugs, smoking (which doubles the risk), stress and the use in women of oral contraceptives.
Kicking the smoking habit
Diagnosis is made by blood tests and stool examination. It may be more difficult to identify if the bowel symptoms are mild or absent and only general symptoms are present. A definitive diagnosis requires colonoscopy (a telescope up into the bowel) with a biopsy of the last part of the small bowel. On diagnosis, smokers are instructed to stop because relapses of the disease drop dramatically following cessation of smoking. Steroid drugs are an immediate first line and are very useful for the short-term control of symptoms because of their immunosuppressant and anti-inflammatory effects.
As with many areas of medicine newer drugs are now being used but azathioprine (or mercaptopurine) is still the mainstay of treatment and, for those patients who cannot tolerate the drug (about 20%), methotrexate is an effective alternative. For patients in poor health, with severe disease or who do not do well with standard therapy, newer immunosuppressant drugs are available; these target a protein called Tumour Necrosis Factor alpha (TNF-α) which is believed to be associated with the inflammation that occurs in Crohn’s disease. The two best known are infliximab and adalimumab. These drugs are normally used for a year and the patient is then reviewed to assess success.
In some patients, where bowel symptoms are persistently severe or where damage is considerable, surgery may be considered to remove diseased bowel. The operation is major and risks must be assessed to ensure that they do not outweigh the advantages. In some cases it is not possible to re-join the bowel after a section has been removed and a stoma has to be formed (the end of the bowel is routed through a hole in the abdominal wall and a bag is fitted externally to collect waste products). With treatment many patients do well and go into remission; treatment may only be required periodically if there are any relapses.
Crohn’s disease may be confused with ulcerative colitis (UC), which also produces inflammation but which is normally confined to the colon. Features include bloody diarrhoea, colicky abdominal pain and weight loss. Many ulcerative colitis sufferers have a range of general symptoms including those similar to Crohn’s disease. UC is about twice as common as Crohn’s disease and peak incidence is between the ages of 15 and 40. A genetic link is associated with 20% of sufferers. Treatment of UC is with the same range of drugs used for Crohn’s disease.
Modern management has improved the lives of very many of the sufferers of both diseases but current developments will continue to improve prognosis.
Differences and similarities between Crohn’s disease and Ulcerative Colitis:
|Ulcerative Colitis||Crohn’s Disease|
|Defaecation mucus-like with blood||May be like porridge|
|Fever indicates severe disease||Fever common|
|Weight loss uncommon||Weight loss common|
|Peak incidence 15-40||Usual onset is third decade|
|Lower risk with smoking||Higher risk with smoking|
|Seldom affects the ileum||Commonly affects the ileum|
|100% affect the colon||About 75% affect the colon|
|Continuous areas of inflammation||Patchy areas of inflammation|
|Continuous ulceration||Discrete S-shaped ulcers|
|Often affects lining of the bowel only||Often affects whole thickness of bowel wall|
|Antibiotics generally not useful||Antibiotics may be effective long-term|
|Often cured by surgery||May recur after removal of diseased area|