Don’t suffer in silence. It is thought that around 115,000 people in the UK are living with Crohn’s Disease but many more people may go undiagnosed due to the stigma attached to the condition.
Dr Steven Mann, consultant gastroenterologist at Spire Bushey Hospital in Watford, takes an in-depth look at Crohn’s Disease, its causes, its effect and the treatments available to sufferers.
What is Crohn’s disease?
Crohn’s disease is a chronic condition of the intestinal tract due to inflammation at any site from the mouth down to the anus. Crohn’s is one of two main conditions associated with bowel inflammation, the other being ulcerative colitis.
Typically patients present in the second or third decade with abdominal pain, diarrhoea and weight loss, but any age group can be affected with a large number of cases developing between the ages of 60 and 80.
The affected segments of the bowel will look red and swollen with ulcers which can lead to strictures (narrowed segments), but also fistulae, which are abnormal connections between two parts of the bowel, or between bowel and skin or other organs such as the bladder.
What causes it?
Patients with Crohn’s have abnormal regulation of the immune system that resides in the wall of the intestine. This is considered to be partly due to genetic susceptibility and, in part, to some unknown environmental stimulus. It is thought that there is no single causal factor in all patients, but several contributing factors in a genetically susceptible individual.
Is it hereditary?
Not exactly. There is no single gene abnormality that is passed down the generations like other purely genetic conditions such as cystic fibrosis or Huntington’s disease. However there are increased risks in family members of affected individuals and there are clusters of cases within families, implying a stronger genetic contribution in some groups.
What is the role of the immune system?
The immune system is there to protect us from foreign antigens (proteins) and to help us fight infections. In the gut, the immune system is huge and contributes a regulatory control without which we would all develop reactions to every organism that resides in the colon and every new protein that we ingest. If the control system is lost then it can lead to gut inflammation and Crohn’s Disease.
How can environmental factors impact it?
The most striking environmental trigger is smoking- smokers have a worse outcome than non-smokers with more operations and more flare-ups requiring steroids. Furthermore, stopping smoking has an extremely positive benefit on the patient’s outcome.
What is the role of stress?
Like a lot of gastrointestinal conditions, stress is known to be an aggravating factor. There are plausible mechanisms by which stress influences the gut to become more inflamed. Although controversial, it is generally considered that flare-ups may be associated with stressful life events such as bereavement, redundancy, etc. However stress is not the cause of the underlying condition. Furthermore, anxious patients may be more susceptible to the impact of stress and anxiety on their gut, leading to more symptoms in general.
What about diet?
There are several dietary factors thought to be associated with a higher incidence of Crohn’s but no single diet has been consistently attributed causing Crohn’s, largely due to the difficulty in recalling intakes of such things as refined sugars or red or processed meat, in the years prior to diagnosis.
Once a patient has established Crohn’s it may be necessary to modify the diet.
Whereas in healthy adults with normal intestines a high fibre diet is recommended this is not the case with many Crohn’s sufferers. Instead a low fibre diet will reduce the risk of blockages, so it is important to avoid things such as fruit and vegetable skins, pith of fruit, pips and seeds, leafy vegetables and other fibrous foods.
What treatments are available?
Treatments range from the very simple and largely ineffective mesalazine preparations, which are well established in ulcerative colitis, to steroids, either prednisolone which is commonly used in short bursts over 6- 8 weeks for flare-ups, or budesonide for ileo-caecal Crohn’s as this is effective for bowel inflammation and has a low risk of side-effects.
If a patient requires recurrent steroids (conventionally two or more courses in any 12-month period), the addition of steroid-sparing drugs may be considered.
These drugs have toxicities and require regular monitoring, but they do reduce the use of steroids and may heal the bowel wall inflammation.
If that fails to adequately control the disease, the patient requires biologics. The main ones, that have been in use since the 1990’s, are Infliximab which is a monoclonal antibody that targets a specific inflammatory protein.
This is given as an infusion every eight weeks; a similar drug called Adalimumab is given by injection under the skin every two weeks. Finally the newest drug to receive NICE approval for use in Crohn’s is Vedolizumab, another monoclonal antibody targeting a different protein, but proven to be a useful alternative for those patients who are intolerant to Infliximab or when the effects wear off.
What about surgery?
Some patients require surgery, either because the disease that is difficult to control with medical therapy or, in cases where there is obstruction due to strictures or other complications.
Can it be cured?
Unfortunately Crohn’s disease is a condition characterised by relapses and periods of remission. Even after medically-induced remission or following a surgical resection of any remaining diseased segment, there is the risk of relapse. We wouldn’t consider this condition as curable but there are some predictors that can guide us as to who will do well in the long term without a recurrence and who will be more likely to have further attacks.
