Irritable Bowel Syndrome: A BJU Gastroenterologist Explains

Do you suffer from irritable bowel syndrome (IBS)? Do you experience abdominal pain, bloating and diarrhea, or constipation? Have you been diagnosed with IBS but want to make sure the diagnosis is correct? In honor of April being IBS Awareness Month, our UK-trained Gastroenterologist Dr. Neil Galletly discusses the symptoms, causes, and diagnosis of IBS.

What are the symptoms of IBS?

The symptoms of IBS can be quite variable. Typical symptoms you might experience include:

• Abdominal pain

The abdominal pain in IBS often feels quite crampy. It typically comes in waves and can sometimes be quite severe. In many cases, going for a poop can temporarily reduce the pain.

• Diarrhea and/or constipation

In some people, their IBS can cause them to have loose or watery stool. They go to the toilet more frequently and may have to rush to the toilet – especially in the morning. Other people experience constipation with straining and less frequent bowel movements. Often, IBS sufferers will have a variable bowel habit – on some occasions, they will have diarrhea and, on other occasions, they will experience constipation. Sometimes, people with IBS see mucus – a white or clear stringy material – in the poop or coating it. They may often feel that they have not completely emptied their bowels after going to the toilet.

• Bloating

Bloating of the abdomen does not occur in all IBS patients but it is a common symptom. You may also have more gas.

Other symptoms that might also occur in IBS include tiredness, nausea, backache, and bladder symptoms (e.g. needing to pee more).

IBS symptoms are normally present for many months – in fact, IBS should not be diagnosed unless you have had symptoms for at least three months. The symptoms may vary in severity and tend to come and go. IBS symptoms can have a big impact on the lives of people who suffer from the disease. People with IBS often find that stress can make their symptoms worse (although stress can also make the symptoms from any abdominal problem worse). Some IBS sufferers also find that certain foods can make their symptoms worse.

Some symptoms would not normally be expected in IBS. These alarm symptoms include:

• Losing weight;

• Seeing blood in your poop;

• Abdominal pain or the need to pass stool that wakes you up at night.

If you experience these alarm symptoms and have been previously been diagnosed with IBS, you should see your doctor or a gastroenterology specialist to question the diagnosis.

Who gets IBS?

IBS is common. In the US and Western European countries, it is estimated that It will affect 10-15% of people at some point in their life, although it is estimated that less than 50% of IBS sufferers will ever consult with a doctor about their symptoms. In China, it seems to be slightly less common with studies suggesting an incidence of 1-11%. IBS is more common in women than in men. It more often occurs in young adults – most cases are diagnosed between the ages of 20 and 30 years. IBS can occur in older people, but it is more unusual – and, as we get older, other causes for abdominal symptoms become more common. I usually try to avoid diagnosing IBS in older patients until I am completely certain that there is no other cause for their symptoms.

Is IBS dangerous?

Although IBS can cause very unpleasant symptoms, it is not life-threatening. IBS does not increase your risk of dying early or developing cancer or other serious diseases. It is however important that your doctor is confident that IBS is the cause of your symptoms – other bowel problems, even cancers, can cause the same sort of symptoms as IBS and may need to be excluded.

What other diseases can cause similar symptoms?

All of the symptoms of IBS can also be caused by other medical conditions and so it is important for your doctor to be confident that IBS is the correct diagnosis. Other diseases that can cause similar symptoms include:

• Inflammatory bowel disease (IBD)

IBD is a condition where, unlike in IBS, there is inflammation in the wall of the bowel. There are two types of IBD: Crohn’s disease and ulcerative colitis. Despite having similar initials, IBS and IBD are very different conditions. IBD can cause abdominal pain, diarrhea, and bloating. Sometimes, unlike in IBS, there may be blood in the poop. 

• Celiac disease 

Celiac disease is an autoimmune condition caused by a reaction to gluten – a protein found in wheat and in other grains such as barley and rye. When the small intestine is exposed to gluten, it causes inflammation and damage to the bowel wall. As a result, the ability of the small intestine to absorb nutrients is reduced. Symptoms of celiac disease include loose or frequent stools, bloating, and difficulty gaining weight, but non-bowel symptoms such as tiredness, headaches, and poor concentration are also common. Celiac disease is more common in people of European rather than Chinese ancestry.

• Giardiasis

Giardiasis is an infection with tiny parasites called giardia. It can be picked up in many countries including China, the USA, and Western Europe. Giardiasis can cause diarrhea, bloating, and crampy abdominal discomfort. 

• Lactose intolerance 

Lactose is a sugar found in milk and dairy products. Sometimes – particularly as we get older or after a bout of gastroenteritis – our bodies lose the ability to digest lactose. The lactose is fermented by bacteria in the gut. This breakdown by the gut causes symptoms of diarrhea, bloating, crampy abdominal pain, and excess gas. Lactose intolerance can occur in anyone but is particularly common in people of Chinese and East Asian ancestry.

• Diverticular disease

In diverticular disease, you develop small, blind-ending pockets in the wall of your colon (large bowel). Sometimes, stool can get stuck in one of the pockets causing inflammation (or diverticulitis). Symptoms include abdominal pain and bloating. 

• Bile acid malabsorption (BAM)

Bile acids are secreted by your liver in bile. They mix with bowel contents in the small intestine and are usually reabsorbed by your body into your bloodstream at the end of the small bowel. In BAM, they are not reabsorbed and enter the colon, causing watery diarrhea and abdominal cramps. BAM is more common after a gallbladder operation or an operation to remove part of the small bowel. 

• Bowel cancer

Colon cancer can cause loose or more frequent stools, or blood in the poop. Abdominal pain and bloating are less common symptoms.

• Gynecological problems 

In women, several gynecological problems can cause similar symptoms to IBS. These include endometriosis and ovarian cancer.

• Anxiety and depression

Sometimes, the effects of anxiety and depression can be felt in our abdomen and may produce IBS-like symptoms. Anxiety and depression can also make IBS symptoms worse. 

Could my symptoms be due to food allergies? 

Allergies to foods are uncommon and can cause much more severe short-term symptoms such as flushing, wheezing, and tingling of your mouth and lips. Food intolerances are much more common and people with IBS symptoms often find that certain foods worsen their symptoms. Food intolerances are not dangerous or life-threatening – allergies can be! Specialist dieticians can help identify food intolerances and triggers for IBS symptoms. (Have dietary requirements? Learn how to navigate Beijing's culinary landscape with your restrictions in mind.)

What causes IBS?

Although IBS is common, the cause is unknown. IBS is called a functional disorder – this means that, although the structure of the bowel appears completely normal, its function is altered. 

Everyone’s bowels contain a huge number of nerve endings within the bowel wall that help control how the bowel works. We believe the problem in IBS lies in the nerve endings in the bowel wall. As a result, the nerves that control how the bowel works ‘misbehave’ and may become oversensitive and overactive. This can change how often you need to go for a poop – and how quickly. It may disrupt the function of the bowel to cause abnormally strong painful contractions and bloating. If the nerve endings are oversensitive, then you might find that even slight stretching of the bowel wall caused by poop in the bowel will be painful. 

We don’t know what causes the change in sensitivity and activity of the nerves in the bowel wall. Possible factors that can contribute to the problem include:

• Stress

The nerve endings in the bowel are connected to nerves in the brain. We believe that stress sensitizes the nerve endings in the gut and can make them overactive and oversensitive.

• Food

There does seem to be a link between IBS and food intolerances. In addition, IBS symptoms can be improved on certain exclusion diets. Foods that our digestive system find hard to digest and process seem to be particularly problematic.

• Infection

IBS is not caused by an ongoing infection. However, IBS can sometimes occur in people after a bout of food poisoning or gastroenteritis. It is not clear why this happens – it is possible the virus responsible for the food poisoning (or the inflammation it causes) sensitizes the gut in some way.

• Natural susceptibility

Some people seem more naturally susceptible to IBS triggers than others. 

Do I need any tests?

IBS is usually diagnosed from the symptoms. There are no tests that confirm the diagnosis of IBS as there are no tests in clinical use that look at the sensitivity of nerve endings in the bowel. Tests that look at the bowel will be normal in IBS. The role of tests is to exclude other conditions that can cause similar symptoms. Blood tests are often helpful to rule out other causes. Blood tests can check for anemia (low red cell count in the blood) and inflammation, as neither of these should be present in IBS. They can also rule out celiac disease. In women, a blood test to rule out ovarian cancer may be useful. Stool tests are often used to rule out inflammation in the gut (which might be elevated in conditions such as Crohn’s disease or colitis). 

If there is doubt about the diagnosis or if you develop IBS symptoms later in life, you may need an examination of the colon with a colonoscopy. This is also the case if you have alarm symptoms such as blood in the stool. 

Isn’t IBS just a label that doctors use when they don’t know the real diagnosis? 

No - IBS is without a doubt a real disease, although many other diseases can cause similar symptoms and there are no diagnostic tests for IBS. However, it is true that sometimes people may be given a diagnosis of IBS that afterwards turns out to be incorrect. If you have been diagnosed with IBS but aren’t sure and want to make sure the diagnosis is correct, then make an appointment to see a gastroenterology specialist. 

Dr. Neil Galletly is BJU’s Section Chief of the Digestive Disease Center. To make an appointment with him, please call the BJU Service Center at 4008-919191. 

• Having digestive issues but they don't sound like IBS? Read about acid reflux to see if that's what you might be suffering from. 

• Keen to learn about colon (bowel) cancer? Dr. Galletly explains.  

• Interested in diverticulitis? Read more here!