What is IBS?

Irritable Bowel Syndrome (or IBS; also been known by a variety of other terms including: Spastic colon, spastic bowel disease, mucous colitis, and colitis) is a Functional Gastrointestinal Disorder (FGID). IBS is identified as a functional disorder of the GI tract due to its symptoms and activity being an interaction of altered gut physiology (due to changes in the actions of the Brain-Gut-Axis) and psychological factors.

IBS is one of the most common medical conditions, affecting an estimated 15% of people in Australia, with a 2:1 female predominance. In fact IBS is responsible for up to 50% of consultations with Gastroenterologists and the second only to the common cold as the leading cause of work absenteeism. While specific Australian-based costs associated with IBS are unknown, the reported cost the US health care system in 1995 was around 8 billion dollars.

According to the established FGID diagnostic criteria (Rome III criteria), to make a diagnosis of IBS, individuals must experience recurrent abdominal pain or discomfort for least 3 days per month (over the last 3 months) with the addition of at least two or more of the following: (1) improvement with defecation, (2) changes in stool frequency, and/or (3) change in stool appearance.

Other symptoms of IBS include: Bloating and gas, mucus in or around stools, changes in bowel habits, for example diarrhoea, constipation, or constipation alternating with diarrhoea. IBS is often associated with other non-gut symptoms including: Fatigue, headaches, bladder irritability, sleep dysfunction, Dysmenorrhoea (discomfort or pain during menstruation), Dyspareunia (pain during sexual intercourse), and Fibromyalgia (chronic, widespread pain in muscles, tendons and joints).

Symptoms NOT characteristic of IBS include: Unexplained significant weight loss, diarrhea that awakens/interferes with sleep, pain that awakens/interferes with sleep, family history of bowel cancer, family history of celiac disease, family history of inflammatory bowel disease, blood in stools, fever and abnormal physical examination of the abdomen.

The exact cause (or causes) of IBS are unknown, however, several factors have been implicated in its pathogenesis. These include: Familial predisposition, visceral hypersensitivity (over sensitivity towards gut movements and activity), Intestinal dysmotility (contraction abnormalities), autonomic dysfunction, post infective IBS (25% report IBS after episode of infective diarrhea), indigenous bacterial flora, and psychological factors.

Evidence for the psychological contribution to IBS is clear. Evidence shows that individuals with IBS report more stressful events and have greater physiological reactions to stress when compared to control groups, such as individuals with no IBS activity. Approximately three quarters of patients report that stress leads to acute abdominal pain and changes in stool patterns. Persons suffering from IBS also tend to have high rates of comorbid psychiatric concerns. Over two thirds of IBS patients have a psychiatric disorder, with the most common concerns being: anxiety, somatization, depression, and pain (e.g., fibromyalgia, chronic pelvic pain, etc).

Numerous treatments have been identified and tried with IBS. In some cases, simple dietary changes (to avoid foods that cause irritation to the GI tract) can be helpful, however this usually only helps a minority of IBS sufferers (<30%). As with any chronic illness, healthy eating and regular exercise and sleep are important. Its is known that engaging in these healthy activities will aid in helping to reduce IBS activity/symptoms. Depending on the nature and type of IBS (diarrhoea predominant, constipation predominant, alternating constipation/diarrhea) various interventions may be useful, however they should be discussed with a General Practitioner or Gastroenterologist.

The most common drug treatments include the use of low-dose antidepressants, called Selective Serotonin Reuptake Inhibitors (or SSRIs) to address abdominal pain, BGA activity and altered gut motility. Lopermide, Cholestyramine, Alosetron can be used to treat diarrhea. Psyllium, sorbitol, etc to treat constipation. Prebiotics or probiotics have also been found to be useful for some individuals suffering IBS.

Several psychological based treatments/strategies have also be tested and found to be help in reducing IBS symptoms; these include Cognitive Behaviour Therapy (CBT), Hypnotherapy, Mindfulness/relaxation, and Interpersonal Therapy. To date, the most effective psychological treatment of IBS, is Cognitive Behaviour Therapy.

Due to the complex nature of IBS, diagnosis should include a careful medical history, history of any coexistent illness, a physical examination, and a family history. Optimal management of IBS involves professionals from a range of disciplines, including, General Practitioner/Gastroenterologists, Psychologists, and other health specialists such as Dietitians and bowel physiotherapists.