10 Minute consultation: Irritable bowel syndrome
A 35 year old woman with longstanding “loose bowels” reports an increasing incidence over two years of painful abdominal cramps and “rumblings,” with frequent loose stools and occasional leakage. Her work is stressful, and she worries that her bowel problems may affect her job performance.
Characteristics - Irritable bowel syndrome consists of abdominal pain and intermittent diarrhoea, constipation, or bloating. Possible contributing factors include stress or anxiety, visceral hypersensitivity, altered bowel motility, neurotransmitter imbalances, and inflammation. No single mechanism explains all cases, and no specific dietary causes are known. Symptoms usually begin before the age of 50, and up to 20% of the population may be affected.
Diagnosis - Differential diagnoses include inflammatory bowel disease, colorectal polyps or cancers, malabsorption (lactose intolerance or coeliac disease), infectious diarrhoea, and thyroid dysfunction. Although irritable bowel syndrome is often considered a diagnosis of exclusion, validated criteria allow positive diagnosis without extensive testing. The Manning criteria have been studied the most, and the presence of three of the six criteria is 66% to 90% sensitive and 61% to 93% specific for a diagnosis if no red flag signs are present (box). Although many doctors usually obtain a full blood