Definition: Irritable bowel syndrome (IBS) is a common and debilitating condition which significantly affects the patient’s quality of life. IBS presents with a cluster of gut symptoms, with the cardinal symptom being abdominal pain with either constipation and/or diarrhoea. The concomitant symptoms include distension and flatulence, with these symptoms varying in frequency and severity between individuals and in the same individual at different points of time.

Key components of the IBS pathology include imbalanced microflora (dysbiosis) with enteric nervous system involvement with visceral hypersensitivity, a major dietary link examined by exclusion of foods and intestinal epithelial barrier defect. Due to the multifactoria
l nature of IBS, an holistic approach is required for lasting results, encompassing diet, lifestyle, and digestive management strategies.

IBS is divided into subcategories based on the predominate symptom. Recognising the patient’s subtype can be important for guiding treatment and monitoring progress.

The four major subtypes are:

• IBS-C (constipated) Hard or lumpy stools > 25 (constipated) Hard or lumpy stools > 25% and loose or watery stools < 25% of bowel movements.

• IBS-D (diarrhoea) Loose or watery stools > 25% and hard or lumpy stools < 25% of bowel movements.

• IBS-M (Mixed IBS) Loose or watery stools > 25% and hard or lumpy stools > 25% of bowel movements.

• IBS-U (Un-subtyped IBS) Insufficient abnormality of stool consistency to meet criteria for IBS-C,D or M

If a practitioner suspects IBS in an undiagnosed patient, it is recommended to refer these patients to their general medical practitioner for assessment, in order to rule out other serious conditions. Note that IBS-like symptoms can also occur periodically in patients without the complete syndrome.
Aetiology/Major causative factors and risk factors that can contribute to the incidence of IBS include:
• Occurs more frequently in women than men
• Most commonly diagnosed younger than 50 years of age
• It is very common, IBS affects almost 20% of Australians and New Zealanders
• Stress
• Depression
• In some cases, eating specific foods, including wheat, dairy products, or citrus fruits
• In some cases, alcohol or caffeine
• Familial predisposition
• Certain drugs (e.g., NSAID’s) can alter the bowel’s normal motility.
• Hormones – menstruation frequently triggers or exacerbates IBS symptoms, while pregnancy and menopause tends to improve symptoms. Hormone replacement therapy is associated with an increased risk of developing IBS.

Signs and symptoms of IBS (including the Rome III Criteria) are:
• Abnormal stool frequency (“abnormal” may be defined as greater than 3 bowel movements per day and less than 3 bowel movements per week)
• Abnormal stool form (lumpy/hard or loose/watery stool)
• Abnormal stool passage (straining, urgency, or fee ling of incomplete evacuation)
• Passage of mucous
• Bloating or feeling of abdominal distension.
• Straining during a bowel movement
• Urgency (having to rush to have a bowel movement)
• Feeling of incomplete bowel movement
• Abdominal pain and/or discomfort relived by defaecating
• Changes in bowel habits
• Diarrhoea or constipation, or both alternately
• Need for bowel movement immediately on waking, or after eating