IBS and IBD - what's the difference? They can both be a pain in the guts. But there are differences, and correct diagnosis means a better chance of effective treatment.

"There is a great difference between IBS and IBD but they can be incorrectly confused," says Anton Emmanuel, consultant gastroenterologist at University College Hospital London. "There can be misdiagnosis by non-specialists, where people with IBD are diagnosed as having IBS, but things are improving as awareness is increasing and better tests are available," says Emmanuel.

IBS, or irritable bowel syndrome, is caused by disturbance of the rate and co-ordination of the gut movement, resulting in it being too fast or too slow. This can be associated with abnormal sensations, typically felt as abdominal pain. Characteristically, the pain occurs when the rate of movement changes. No gut inflammation is involved.

IBS affects about 15 per cent of the population and is more common in women, especially those of childbearing age. There is no genetic link - instead the causes are found within the patient's environment. "Symptoms can be triggered by stressful life events," says Emmanuel.

IBD, or inflammatory bowel disease, affects less than one per cent of the population. It involves inflammation, which can be see under a microscope or even with the naked eye, and it can affect the colon, the small bowel or both.

IBD symptoms include abdominal pan, diarrhoea which may be bloody, and, if the small intestine is inflamed, malnutrition and lethargy caused by malabsorption of food.

With IBD, there is a strong genetic link. "Certain genes are associated with, for instance, Crohn's disease, which is a type of IBD," says Emmanuel.

So, if you suspect you have IBS or IBD, what can you do?

Do not rely on the internet for a diagnosis. Go along to your GP.

New screening procedures can help in the diagnosis of IBD. Simple stool tests will reveal the level of the inflammatory protein calprotectin. "If the level is low and you have none of the characteristic symptoms of IBD, it is usually ruled out," says Emmanuel. "If the levels are high you may be referred for a colonoscopy, gastroscopy or MRI, depending on whether IBD is suspected to affect the colon or small bowel."

Once diagnosed IBD patients may be referred to an IBD nurse specialist - a service in which the UK leads the world - and which has transformed access to care. Treatments vary but usually include drugs or less commonly surgery.

There is no specific test for IBS. "When suspected it is common for patients to be sent away with general advice to look after themselves, but patients need better guidance," says Emmanuel.

Treatment and care depends of the type of IBS, and Emmanuel suggests that if simple measures don’t help, patients ask for referral to a team with an interest. Care may include lifestyle changes to minimise stress, dietary advice, including eating two to three meals a day, and drinking at least 1.25 litres of liquid daily (as dehydration can worsen constipation as part of IBS).

Patients should search out reliable sources of information from charity sites such as www.corecharity.org.uk, theibsnetwork.org, and http://www.crohnsandcolitis.org.uk.