What is Irritable bowel syndrome?
Irritable bowel syndrome (IBS) is a chronic, often debilitating, functional gastrointestinal (GI) disorder affecting as many as 13-20% of Canadians at any given time. The lifetime risk for a Canadian to develop IBS is 30%. IBS is the most common disorder diagnosed by gastroenterologists and is a common reason why many people visit their primary care physician. IBS can begin in childhood, adolescence, or adulthood, and can resolve unexpectedly for periods throughout an individual’s lifespan, recurring at any age.
IBS is generally classified as a functional disorder because it impairs the functioning of the body’s normal activities, such as the movement of the intestines, the sensitivity of the nerves of the intestines, or the way in which the brain controls some of these functions.
What Causes IBS?
While the exact cause of IBS is not clear, we do know that IBS is a multifactorial disorder that likely involves an interaction between the GI tract, bacteria in the gut, the nervous system, and external factors, such as stress.
Possible causes include:
- Emotional factors such as stress, anxiety, depression, and fear
- Dietary issues such as food allergies or sensitivities, or poor eating patterns
- Drugs such as laxatives and antibiotics
- Bile acid malabsorption
- Lack of physical activity
- Chronic alcohol abuse
- Abnormalities in GI secretions and/or digestive muscle contractions
- Acute infection or inflammation of the intestine, such as traveller’s diarrhea
- Neurological hyper-sensitivity within the GI nerves
What Are IBS signs and Symptoms?
Individuals might have different combinations of symptoms, with one symptom dominating while the other digestive symptoms may occur randomly and unpredictably. These unpredictable bowel experiences can lead to a high degree of anxiety for the IBS patient and can significantly decrease a person’s quality of life.
In many people with IBS, the digestive tract is especially sensitive to many stimuli. People may experience pain caused by intestinal gas or contractions that other people do not find distressing. Pain manifests in many ways with IBS. The abdominal pain related to or relieved by having a bowel movement can be ongoing or episodic, present sharply and resolve rapidly, occur occasionally or frequently, and move from one location in the bowel to another very quickly. Digestive pain often occurs following a meal and can last for hours. Those who have IBS tend to have a quicker and more intense reaction to digestive tract pain stimuli than those who do not have IBS.
Other common symptoms of IBS include change in stool frequency or consistency (such as constipation and diarrhea), abdominal distention, the sensation of incomplete emptying after defecation, cramping, bloating, belching, flatulence, nausea, headaches, fatigue, difficulty sleeping, depression, anxiety, muscle aches, and difficulty concentrating.
IBS has different sub-groups, which are associated with stool consistency.
- IBS-D is when the digestive system contracts quickly, transiting products of digestion rapidly through the digestive tract, resulting in diarrhea.
- IBS-C is when the digestive system contracts slowly, delaying transit time for products of digestion, resulting in constipation.
- IBS-M is when the transit time throughout the digestive tract fluctuates, causing patients to experience a mix of both diarrhea and constipation, often alternating between the two.