Inflammatory Bowel Disease (IBD)
Crohn's disease and Ulcerative Colitis are two of the most important diseases in a group of conditions collectively known as inflammatory bowel disease. The incidence of these conditions in children appears to be increasing, particularly Crohn's disease. Both conditions are chronic and when affecting children will extent into adult life. The aetiology of these conditions is still unknown, although the current evidence would suggest that the immunological response in the gut has been altered such that it reacts to normal bacteria that are found there.
The onset of this condition is often vague, and it may take time before the diagnosis is made. The pathology is inflammation of the gut through the full thickness of the wall. Any part of the gut may be involved from the mouth to the anus. The intestine in between the inflammation may be normal, i.e. it's patchy.
The symptoms of Crohn's Disease will depend on the site of intestine involved. The most common symptoms are, abdominal pain and weight loss. There is often a lack of appetite but studies have shown that the poor growth is also a result of the response to inflammation. Diarrhoea is common, and if the colon is involved, may be associated with blood.
Involvement of the mouth can result in mouth ulcers and swelling of the lips. In the anal margin there may be fleshy tags of tissue, or occasionally fistulae. These are tracts or connections from the bowel to the surface of the skin. These can become infected in which case they may result in pain.
A simple blood test may suggest the need for further investigation. Crohn's disease is often associated with low haemoglobin, high platelet count, low albumin, high ESR, and a raised C-reactive protein concentration.
The aims of further examination are to both establish a tissue diagnosis, and work out the extent and location of the disease. This is best achieved by a colonoscopy, and in most cases gastroscopy. One of the most common sites of Crohn's disease is the terminal ileum (the junction of the small and large bowel). It is important therefore that this is reached at endoscopy.
The remainder of the small bowel can be visualised by radiology. MRI is currently superseding the use of barium with contrast. This gives much more detail of inflamed areas but does not involve radiation, an important consideration in a chronic disease with the need for repeated examinations.
The mainstay of treatment in children with Crohn's disease is the use of a liquid diet such as Modulen. This is a whole protein milk, the mechanism of action is unknown, but it has been shown to reduce inflammation and improve growth. The diet is given for 6 weeks with no other food. This is then reintroduced slowly in a stepwise manner for a further 6 weeks. Some children who do not respond need steroids.
Once a remission of symptoms has been achieved then medication is required to prevent a relapse. Most centres will use an ASA type drug such as Pentasa. This will be required for many years. Further patients will need modulation of the immune system if no response has been achieved; commonly used drugs are Azathioprine, or occasionally methotrexate.
A current advance in the treatment of resistant disease has been the use of the so-called biological agents. The best known of which is Infliximab. This is given by intravenous infusion, in cycles commonly of 8 weeks. This blocks the production of tumor necrosis factor, and results in marked suppression of the immune system and is used only with close monitoring. This treatment has been found to be very effective in perianal disease
This is often needed in the management of Crohn's disease. As a result of the inflammation through the whole wall of the intestine strictures or areas of narrowing may develop. Surgery is required to remove these areas. It is important to realise that this does not cure the disease, but simply alleviates the symptoms.
Ulcerative Colitis is similar to Crohn's Disease but has several important differences. This condition only affects the large intestine, and produces a superficial inflammation or ulcers. This means that the symptoms are often more acute, and obvious.
Rectal bleeding and diarrhoea are the predominant symptoms. There may also be abdominal pain. Rarer associations with pain in the joints and skin conditions such as erythema nodosum may also occur. The dramatic presentation means that late diagnosis is rare.
Bloods tests again suggest inflammation with a low haemoglobin, high platelet count, low albumin level, raised ESR, and elevated C-reactive protein levels. It is also mandatory to exclude infection with a stool culture.
Colonoscopy is essential to make the diagnosis. This delineates the amount of colon involved, and gives tissue available to confirm the diagnosis, and exclude Crohn's disease. MRI is also performed to exclude Crohn's disease as in Ulcerative Colitis the small bowel is not involved.
Unlike Crohn's disease, UC does not respond to a diet. The mainstay of therapy and induction of a remission is the use of ASA drugs such as Mesalazine. If the inflammation only extends to the distal part of the colon (that part closest to the rectum or anus), then enemas or suppositories may only be required. If there is no response then treatment has to be escalated to steroids.
Like Crohn's disease the condition is chronic and an ASA is needed daily to prevent a relapse. If repeated relapses occur then the use of immunomodulation with Azathioprine may be needed. It has to be recognised that repeated courses of steroids in children would adversely affect their growth.
This is a serious complication particularly in Ulcerative Colitis. The colon becomes very distended, the child becomes toxic or shocked and in severe pain. The risk is the bowel will perforate. This may be associated with infection such as C.difficile. Treatment is essential in centres used to dealing with IBD and access to surgery. IV antibiotics, and steroids are commenced. A scoring system of severity such as a PUCAI score is monitored to identify deterioration. Although increasing anti suppressant agents such as cyclosporine, or biological agents such as Infliximab may save the colon, a significant number of children in this situation will need colectomy at some stage.
Some patients with Ulcerative Colitis, and rarely Crohn's disease will develop a condition known as Sclerosing cholangitis. This can progress to cirrhosis. All children with IBD need regular monitoring of liver function.
All patients with established colitis for longer than 10 years must have regular colonoscopy to exclude the development of malignant change. If detected early this is usually cured.
IBD in children must be managed in centres that are used to dealing with the condition. This means that the child has access to a full team including dieticians and clinical nurse specialists.
Much more information and practical help is available by both NACC and CICRA organisations.