Role of visceral sensitivity in the pathophysiology of irritable bowel syndrome

Abstract

Visceral hypersensitivity has been recognised as a characteristic of patients with irritable bowel syndrome (IBS). It may be involved in the pathogenesis of abdominal pain/discomfort, and seems to result from the sensitisation of nerve afferent pathways originating from the gastrointestinal tract. From a clinical point of view, hypersensitivity, although frequent, is not a constant finding among patients with IBS and cannot therefore be considered as a diagnostic marker of the condition. The advances made in understanding visceral hypersensitivity in patients with IBS are reviewed: the factors that influence abdominal distension are defined and different therapeutic perspectives are examined.

Figure 1

Schematic organisation of afferent nerve pathways originating from the gastrointestinal tract.

Figure 2

Various distension protocols used to measure sensory thresholds in patients with irritable bowel syndrome. With the tracking technique, subjects receive multiple distensions at around the threshold level in order to track their response. The double random staircase method uses the barostat to deliver two randomly mixed scales of impulse progression so that the stimulus cannot be predicted by the subject. *Positive response.