We usually use it as a term to cover two diseases: firstly, ulcerative colitis, and secondly, Crohn’s disease.
Ulcerative colitis is an inflammatory disorder of the large bowel affecting
the colon, which produces blood and diarrhea. That’s what patients experience when they
have flares of ulcerative colitis and it tends to proceed in a relapsing and remitting way
so that for long periods of time, patients can have periods of remission, but then from
time to time, they can have active flares. Crohn’s disease is a different disease discovered
by a New York physician called Burrill B. Crohn in the 1930s, which is characterized
by inflammation anywhere in the gut from mouth to anus, and that classically tends to present
with abdominal pain and diarrhoea rather than bleeding, although, in a small proportion
of cases, it can present with bleeding as well as with pain around the bottom or pain
higher up in the digestive tract, such as the oesophagus or the stomach.
The ways in which inflammatory bowel disease affects the digestive system depends on whether
the disease is ulcerative colitis or Crohn’s disease. Ulcerative colitis tends to affect
just the colon or the large bowel and therefore, in general, it presents with bleeding from
the back passage and diarrhoea. It can vary in the amount of the colon that it involves
so patients can sometimes get just bleeding associated with some urgency or some frequent
visits to the bathroom, or, if the disease affects a larger part of the bowel,
there can be a rather unpleasant mixture of blood and diarrhoea, which, again, can affect the patient
with frequent visits to the lavatory, sometimes getting them up in the middle of the night.
Crohn’s disease most commonly presents with
abdominal pain and diarrhoea, although in a small proportion of patients, if the large
bowel is affected, a bit like colitis, it can produce bleeding and if other parts of
the digestive tract are involved like the oesophagus, the gullet, or the stomach,
it can present with upper abdominal pain, indigestion-type symptoms, or
problems with swallowing.
Sometimes, Crohn’s can affect the bottom area – so-called perianal disease – when it can produce some
discharge or some discomfort around the bottom.
Inflammatory bowel diseases – ulcerative colitis and Crohn’s disease –
can sometimes affect other parts of the body.
In about 15 or 20% of cases, patients can get joint symptoms,
either because the joints are involved or because patients get sore joints,
which can sometimes mirror the activity of the inflamed intestines.
It’s not just the joints that can be affected,
because sometimes, for reasons that we know something about, but not everything about,
the diseases can affect the liver and this produces a condition called PSC or
primary sclerosing cholangitis – big medical label, but what it actually means is inflammation
of the liver which goes with inflammatory bowel disease.
Sometimes the skin can be affected. There are various inflammatory conditions called
pyoderma or erythema nodosum, again, just sort of Latin labels, but detailing rather
nasty, painful inflammatory conditions of the skin, usually which are active when the
inflammatory bowel disease is active.
Finally, the eyes can be affected with some sore red eyes called iritis or uveitis.
These diseases are not just affecting the bowel, but can affect other systems of the body as well.
Patients often ask if inflammatory bowel diseases can be fatal. This is really very unusual.
It’s true that the diseases can be serious, so that ulcerative colitis can affect the
whole of the colon and doesn't always respond to medical treatment and can need surgery.
But it’s extremely uncommon for it to be fatal, unless the disease is missed or not
treated or results in complication such as a perforation of the bowel. In this situation,
an unpleasant and rather debilitating disease can turn into a dangerous and life-threatening
disease with peritonitis. This would then be a surgical emergency.
Crohn’s disease can affect any part of the digestive tract and can affect absorption
of food and nutrients. In some unfortunate patients who have had Crohn’s in a very
severe way affecting their small bowel, they can become nutritionally very compromised
and require intravenous feeding and there is a certain amount of mortality associated
with this type of Crohn’s, although once again, with modern management, it’s extremely
unlikely and uncommon for Crohn’s disease to directly be associated with fatality.
Patients often ask me whether inflammatory bowel disease can be cured and the short answer is no.
Interestingly, the cause of inflammatory bowel disease, while it’s not known, is
a very active area of study and we’re finding out a lot about this quite quickly.
In brief, people have thought that Crohn’s disease is an autoimmune condition for very many years,
but I think that the current research into genetics is giving us a lot of information
that Crohn’s disease may, in fact, result from a failure of dealing with intestinal
antigens and bacteria. We know that the bacteria in the gut are very, very relevant to the
cause of Crohn’s. However, while this may lead to some more effective therapeutic innovations
in the future, at the moment, we can't say that we can cure Crohn’s disease.
Similarly with colitis, the mechanism is likely to be different. One day we may be able to
cure these diseases but at the moment, there is no definite cure for ulcerative colitis,
although we can induce prolonged periods of remission for years at a time.