Visceral pain hypersensitivity in functional gastrointestinal disorders.
BACKGROUND
Functional gastrointestinal disorders (FGIDs) are a highly prevalent group of heterogeneous disorders whose diagnostic criteria are symptom based in the absence of a demonstrable structural or biochemical abnormality. Chronic abdominal pain or discomfort is a defining characteristic of these disorders and a proportion of patients may display heightened pain sensitivity to experimental visceral stimulation, termed visceral pain hypersensitivity (VPH).


METHODS
We examined the most recent literature in order to concisely review the evidence for some of the most important recent advances in the putative mechanisms concerned in the pathophysiology of VPH.


RESULTS
VPH may occur due to anomalies at any level of the visceral nociceptive neuraxis. Important peripheral and central mechanisms of sensitization that have been postulated include a wide range of ion channels, neurotransmitter receptors and trophic factors. Data from functional brain imaging studies have also provided evidence for aberrant central pain processing in cortical and subcortical regions. In addition, descending modulation of visceral nociceptive pathways by the autonomic nervous system, hypothalamo-pituitary-adrenal axis and psychological factors have all been implicated in the generation of VPH.


RESULTS
Particular areas of controversy have included the development of efficacious treatment of VPH. Therapies have been slow to emerge, mainly due to concerns regarding safety.


CONCLUSIONS
The burgeoning field of genome wide association studies may provide further evidence for the pleiotropic genetic basis of VPH development.


CONCLUSIONS
Tangible progress will only be made in the treatment of VPH when we begin to individually characterize patients with FGIDs based on their clinical phenotype, genetics and visceral nociceptive physiology.
Farmer
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AD
Neurogastroenterology Group, The Wingate Institute of Neurogastroenterology, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, Whitechapel, London E1 2AJ, UK.
Aziz
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Q
D015746:Abdominal Pain / Q000209:etiology / Q000503:physiopathology; D005767:Gastrointestinal Diseases / Q000150:complications* / Q000503:physiopathology; D006801:Humans; D006930:Hyperalgesia / Q000209:etiology* / Q000503:physiopathology; D009619:Nociceptors / Q000502:physiology; D013315:Stress, Psychological / Q000150:complications; D017833:Visceral Afferents / Q000502:physiology