31.JAN.2019 7 MIN READ | 7 MIN READ

Having abdominal pain, constipation, persistent diarrhoea or even bloody stools? Dr Tan Chi Chiu, gastroenterologist at Gleneagles Hospital, explains what might be going on inside your gut.

Every one of us has experienced altered bowel habits at some point or another, be it constipation, loose stools or changes in stool frequency or colour. Perhaps you had some ‘bad’ food. Perhaps you’re lactose intolerant and drank too much milk. Perhaps travelling overseas triggered a bout of traveller’s diarrhoea.

For the most part, minor and short-term changes in bowel habits are often harmless. They may be caused by benign reasons such as changes in dietary intake, lack of physical exercise, or taking certain medications. Usually they can be eased by dietary modifications, lifestyle changes and medication if necessary and they resolve reasonably easily.

But if your bowel problems start to become chronic (persisting beyond 1 – 2 weeks), or if you experience other disturbing symptoms such as severe pain and rectal bleeding, you should immediately seek medical care to find out if there is something more serious going on.

What is causing my bowel troubles?

When it comes to gastrointestinal disorders, you often hear 2 terms being used: Irritable Bowel Syndrome (IBS) and Inflammatory Bowel Disease (IBD).

IBS is a benign but troublesome condition of uncertain cause that involves symptoms such as abdominal pain or cramps, bloating, changes to bowel habits towards constipation, diarrhoea or a mix of both, incomplete or unsatisfactory bowel movements or changes in stool consistency. It is a very common condition and is estimated to affect around 10 – 20% of the Singapore population.

IBD, on the other hand, is an umbrella term for disorders involving chronic inflammation of the gastrointestinal tract. When inflamed, the intestinal wall becomes swollen and develops ulcers, which sometimes lead to serious damage to the digestive system over time. Symptoms typically include abdominal pain, diarrhoea, bloody stools, fatigue, and weight loss. Although less common than IBS, IBD has become increasingly prevalent in Asia over the last decade – there are estimated 2,000 patients in Singapore today.

It is important to note that while IBS and IBD share some overlapping symptoms (such as abdominal pain and diarrhoea), they are actually completely different conditions. IBS is a benign syndrome, meaning that while it comes with a constellation of bothersome symptoms, it does not lead to serious health issues or complications, although quality of life may be significantly affected. IBD, on the other hand, is an inflammatory disease, meaning that it is potentially much more debilitating and can lead to serious complications such as severe bleeding, obstruction or rupture of the intestines and in some cases is related to development of cancers such as of the colon or bile ducts.

What should I know about IBD?

Crohn's disease and ulcerative colitis - digestive problems

There are 2 main types of IBD: ulcerative colitis and Crohn’s disease.

Ulcerative colitis, as its name suggests, occurs only in the colon (large intestine). There is continuous inflammation and, if severe, ulceration of the colon, typically at the innermost lining. The inflammation can be of varying extents. It always starts in the rectum but can affect the entire colon. The more affected the colon is, the worse the symptoms will be.

Unlike ulcerative colitis, Crohn’s disease can affect any part of the gastrointestinal tract, from the mouth all the way to the anus. Instead of continuous inflammation, inflamed areas appear in between healthy parts of the intestine. Crohn’s disease can occur in all layers of the bowel walls, presenting as either shallow crater-like areas or deep lesions, leading to complications such as scarring and stricture of the intestines as well as abnormal connections between loops of intestines, called fistulae.

Key differences between ulcerative colitis and Crohn’s disease

Ulcerative colitis

Crohn’s disease

Occurs in the colon

Occurs anywhere in the gastrointestinal tract, though most commonly at the tail end of the small intestine

Affects only the innermost lining of the colon

Affects all layers of the intestine walls

Inflamed area is continuous

Inflamed areas may appear in patches next to healthy parts of the intestine

Possible complications: perforated colon, toxic megacolon, severe dehydration, colon cancer

Possible complications: bowel obstruction, fistulae, anal fissures, malnutrition, colon cancer

Both ulcerative colitis and Crohn’s disease can strike at any age, though they are most commonly seen in teenagers and young adults aged 15 – 35. The signs and symptoms of both diseases are largely similar, including but not limited to:

  • Abdominal pain and cramping
  • Bloating or distension
  • Blood or mucus in the stools
  • Loss of appetite
  • Persistent diarrhoea
  • Fever and fatigue
  • Unintended weight loss
  • Inflammation of the skin, eyes or joints
  • Delayed growth and sexual maturity in children

These symptoms may come and go or be progressively more severe. IDB patients may experience flare-ups, when the disease is active and the symptoms are very severe, or they may undergo periods with few or no symptoms at all, when the disease is in remission, usually after appropriate treatment.

How do I confirm if I have IBD?

If you have persistent, bothersome symptoms related to the abdomen and the bowels or associated systemic symptoms such as lethargy, loss of appetite or weight, speak to a gastroenterologist, who will take your history carefully and may run some diagnostic tests to identify the cause of your bowel symptoms. These tests can range from relatively noninvasive procedures (such as a blood and stool tests) to imaging (such as CT scans and MRI) to minimally invasive procedures (such as gastroscopy and colonoscopy).

Making an early diagnosis of IBD is important as any delay can lead to a higher risk of complications. IBD patients also do less well if their condition has been poorly controlled for a long period of time. It is equally important to exclude serious diagnoses such as IBD and make a clear and confident diagnosis of IBS so that this can be managed appropriately to improve quality of life.

Is there any way to prevent or treat IBD?

Crohn's disease and ulcerative colitis - way to treat IBD

Unfortunately, the exact cause of IBD is still unknown, although it is postulated to be related to dysfunction in the immune system. However, we do know that certain risk factors, such as genetics, immune system abnormalities, smoking (positive relation with Crohn’s disease, but negative for ulcerative colitis) and a more Westernised diet, have been associated with a higher chance of developing IBD.

Treatment of IBD depends on the severity of the disease and its responsiveness to available therapies. For example, a mild case of ulcerative colitis may be controlled with anti-inflammatory medication such as Mesalazine. But for more severe cases, immunosuppressives such as corticosteroids (prednisolone or hydrocortisone) may also be required. If a patient becomes steroid dependent to remain well, other immune suppressive drugs such as Azathiaprine or Methotrexate may be substituted to avoid the long term side effects of corticosteroids. Sometimes biologics may even be used – these are powerful molecules injected either intramuscularly, intravenously or subcutaneously to target specific proteins that cause inflammation and help actively suppress the immune system.

As with all drugs, there are potential side effects to be aware of. Since treatment is often lifelong, your gastroenterologist would have a serious discussion with you on which medications to put you on and for how long. Most doctors would try to control IBD using the least amount of medication and the least dangerous kinds of medication possible.

In severe cases of IBD, where the disease isn’t responding to medication or where the patient’s life is in danger, surgery may be necessary as the last resort. According to estimates, around 25% of patients with ulcerative colitis and up to 75% of patients with Crohn’s disease will require one or more surgeries in the course of their lifetime to help treat their IBD.

In general, the earlier IBD is diagnosed and controlled, the less likely patients will require surgery. Consult a gastroenterologist if you’re concerned you may have IBD or other digestive conditions.


Article reviewed by Dr Tan Chi Chiu, gastroenterologist at Gleneagles Hospital


Change in Bowel Habit. Retrieved 9 January 2019 from https://www.singhealth.com.sg/patient-care/conditions-treatments/change-bowel-habit

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Inflammatory bowel disease, which increases risk of colon cancer, is on the rise. Retrieved 9 January 2019 from https://www.straitstimes.com/singapore/health/inflammatory-bowel-disease-which-increases-risk-of-colon-cancer-is-on-the-rise

With a Can’t Wait card, patients with chronic conditions hope to jump toilet queues. Retrieved 9 January 2019 from https://www.straitstimes.com/singapore/health/with-a-cant-wait-card-patients-with-chronic-conditions-hope-to-jump-toilet-queues

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Tan Chi Chiu
Gleneagles Hospital

Dr Tan Chi Chiu graduated from the National University of Singapore in 1983. He pursued specialist training in Internal Medicine and obtained his Memberships of the Royal Colleges of Physicians of the United Kingdom and Ireland, as well as his Master of Medicine in Internal Medicine in 1988. Dr Tan specialised in Gastroenterology and was accorded the Fellowship of the Academy of Medicine in Gastroenterology in 1993 and recognised by the Ministry of Health as a specialist in Gastroenterology. He was further conferred the Fellowships of the Royal Colleges of Physicians of Edinburgh and London in 1996 and 1998 respectively.