Bloating, cramps, constipation, diarrhoea… These symptoms can make life miserable at times and if they are happening on a regular basis they can require investigation.

“IBS and IBD affect one in five of the Irish population, so they are very common conditions,” says Dr Billy Stack, a consultant gastroenterologist based at the Bon Secours Hospital in Cork.

“They are characterised by abdominal discomfort and some form of irregular bowel habit – diarrhoea or constipation, alone or in combination. The definition that we use for clinical trials is that the patient would have these symptoms for more than three to 12 weeks.”

In practice, patients may have the first type – IBS or irritable bowel syndrome – symptoms for many, many years, he says.

“This is a part of what we call a functional bowel disorder, which are disorders of the function of the bowel as opposed to problems with the structure of the bowel.”

With irritable bowel syndrome (IBS), patients have a lot of symptoms as described above but when investigations are done no abnormalities are found, he states.

“That’s the crucial thing. Scopes - endoscopy, colonoscopy and biopsy are all completely normal, so it’s basically a nervous condition of the bowel where there is an over-sensitivity of the nerve endings in the gut.”

The vast majority of people with these symptoms often don’t go to a doctor, he says.

“They’d just recognise the pattern of the gut itself. Some people might have a runny stool if they get nervous or are under stress, for example.”

IBS – Symptoms happen more frequently

For people who have irritable bowel syndrome, this happens more frequently and with less provocation.

“Many patients wouldn’t go to their GP with this but if they did, GPs in the vast majority of cases would recognise that this is a very benign condition and wouldn’t send them to a specialist.”

Crossover with coeliac disease

Irritable bowel syndrome symptoms can crossover with a number of pathological symptoms of the gut, he adds.

The one most commonly seen is coeliac disease, which is an intolerance to gluten (a component of wheat) in the diet.

“About 1% of the Irish population has coeliac disease. That means 50,000 people in Ireland have it. If you are having IBS symptoms, it would be important to rule out coeliac disease. There are also wheat or food intolerances but these are much more difficult to diagnose as there aren’t good tests to diagnose them.

“Food intolerance does exist but it is important if you are following an exclusion diet (excluding particular foods in order to find out which ones are causing you symptoms) that you see a dietitian first. This is so that you are covering your bases in relation to getting a good spread of nutrition.”

Lowfodmap diet and probiotics can be effective for IBS

Research is now finding, he says, that there are diets which are quite effective for IBS, eg the Low FODmap diet.

This is where fermentable carbohydrates like legumes, eg onions, beans, are withdrawn from the diet because these ferment in the gut and cause bloating.

“These carbs are taken out then gradually re-introduced – but this should be under dietary control. Probiotics are showing promising results also. The gut contains a huge amount of bugs, mainly good, which are very important to maintain a good digestive system and processing of food. Probiotics can be effective, with dietary manipulation, in relieving the symptoms. However, always seek a dietitian’s advice first before going through any exclusion diet.”

In contrast to irritable bowel syndrome, Crohn’s disease and its related condition, ulcerative colitis, come under the medical umbrella of inflammatory bowel disease or IBD.

“These are conditions where the immune system in the gut become active to the point it causes ulceration, bleeding and inflammation, but for reasons that are not fully understood,” Dr Stack says.

“There is a certain genetic component because this runs in families. Smoking is also a factor in Crohn’s disease. Anti-inflammatory medications can provoke these conditions, too.”

Crohn's diseas

In Crohn’s disease, inflammation can occur anywhere from the mouth to the anus. Blockages can occur too.

“It’s not a particularly common condition – 5.9 per 100,000 of the population – so it’s far less common than IBS. With Crohn’s disease there are two peaks (in its incidence). One is between the ages of 15-30 and again as patients get older, between the ages of 50-70. Usually with Crohn’s disease you get abdominal pain, alteration of bowel habit, weight loss, more profuse diarrhoea and a higher temperature. A person with this would be a sicker patient than someone with IBS.”

Ulcerative colitis

The other IBD condition is called ulcerative colitis.

“This is where the colon or last part of the bowel – the one metre drying apparatus for the gastro-intestinal tract – becomes inflamed.

“If this happens it generally starts in the rectum and then moves forward to involve the large bowel or colon. That’s called colitis. This is characterised by abdominal discomfort and bloody diarrhoea – a classic symptom of ulcerative colitis.

“Again, this is where the immune system becomes overactive in the colon and gives you these problems and symptoms. Patients get frequent bloody stools and lower abdominal cramps and experience weight loss if the inflammation is very severe.”

Polyps – what are they?

Polys are growths that occur in the colon.

“At any time, about a quarter of the population that we do scopes on (endoscopy or colonoscopy) will have these polyps but there are a number of different types,” Dr Stack says.

“There are hyperplastic or quite benign ones, and then there are adenomatous ones that are more dysplastic. This is where the tissues are becoming a little more irregular. There are gradings like high and low also, and as you get a larger polyp the level of disorganisation of the tissue becomes more, leading to high-grade dysplasia. That grows into a cancer. That’s how we think the cancer forms.

“Often a polyp can be either a classic polyp or these days we recognise flatter polyps that grow along the surface of the bowel which can be more difficult to see.”

So what causes the polyps to grow?

“It’s an ageing process for the bowel so there are certain familiar characteristics – for example, patients who have colon cancer in the family tend to have a small number of polyps. Then there are various polyp syndromes where patients will be genetically programmed to have hundreds of polyps – but that’s quite rare.

“Less than 5% of colon cancers would come from polyps. The vast majority we see are what we’d call sporadic cancers.

“With cancer, the way we think it happens is that a polyp develops into a cancer, gets larger, spreads into the local lymph nodes and then the various tissues – ie it metastasizes. That’s how a bowel cancer will ultimately kill you.”