IRRITABLE BOWEL SYNDROME GASTROENTEROLOGY IRRITABLE BOWEL SYNDROME (IBS) COMMUNITY PHARMACY LECTURE NO.18 1 1

BACKGROUND Functional bowel disorder (i.e. absence of abnormality) in which abdominal pain and bloating is associated with a change in bowel habit. The diagnosis is suggested by the presence of longstanding colonic symptoms without any deterioration in the patient's general condition.

AETIOLOGY No anatomic cause can be found. Many factors can contribute to disease expression and include motility dysfunction, diet and genetics (In a small proportion of cases symptoms appear after bacterial gastroenteritis).

AETIOLOGY (continued) Psychological factors also influence symptom reporting (stress or depression). Symptoms of diarrhoea and constipation appear to be linked with hyperactivity of the small intestine and colon in response to food ingestion and parasympathomimetic drugs.

ARRIVING AT A DIFFERENTIAL DIAGNOSIS IBS is essentially a diagnosis of exclusion and a careful and thorough history of the patient is essential. Diagnostic aids, such as rectal examination and biopsy, which can be used by GPs are of limited use.

CLINICAL FEATURES OF IBS IBS is characterized by abdominal pain or discomfort, located especially in the left lower quadrant of the abdomen, which is often relieved by defecation or the passage of wind. Altered defecation, either constipation or diarrhoea, with associated bloating is also normally present.

CONDITIONS TO ELIMINATE Constipation and diarrhoea Since the major presenting symptom of IBS is an alteration in defecation, it is necessary to differentiate IBS from acute and chronic causes of constipation and diarrhoea.

CONSTIPATION