Irritable Bowel Syndrome: Aziz Q

Spiller R, Aziz Q, Creed F, Emmanuel A, Houghton L, Hungin P, Jones R, Kumar D, Rubin G, Trudgill N, Whorwell P, Anonymous00175. · Wolfson Digestive Diseases Centre, University of Nottingham, Nottingham, UK. · Gut. · Pubmed #17488783 No free full text.

Abstract: BACKGROUND: IBS affects 5-11% of the population of most countries. Prevalence peaks in the third and fourth decades, with a female predominance. AIM: To provide a guide for the assessment and management of adult patients with irritable bowel syndrome. METHODS: Members of the Clinical Services Committee of The British Society of Gastroenterology were allocated particular areas to produce review documents. Literature searching included systematic searches using electronic databases such as Pubmed, EMBASE, MEDLINE, Web of Science, and Cochrane databases and extensive personal reference databases. RESULTS: Patients can usefully be classified by predominant bowel habit. Few investigations are needed except when diarrhoea is a prominent feature. Alarm features may warrant further investigation. Adverse psychological features and somatisation are often present. Ascertaining the patients' concerns and explaining symptoms in simple terms improves outcome. IBS is a heterogeneous condition with a range of treatments, each of which benefits a small proportion of patients. Treatment of associated anxiety and depression often improves bowel and other symptoms. Randomised placebo controlled trials show benefit as follows: cognitive behavioural therapy and psychodynamic interpersonal therapy improve coping; hypnotherapy benefits global symptoms in otherwise refractory patients; antispasmodics and tricyclic antidepressants improve pain; ispaghula improves pain and bowel habit; 5-HT(3) antagonists improve global symptoms, diarrhoea, and pain but may rarely cause unexplained colitis; 5-HT(4) agonists improve global symptoms, constipation, and bloating; selective serotonin reuptake inhibitors improve global symptoms. CONCLUSIONS: Better ways of identifying which patients will respond to specific treatments are urgently needed.

Aziz Q. · No affiliation provided · Gastroenterology. · Pubmed #16890617 No free full text.

This publication has no abstract.

Rapps N, van Oudenhove L, Enck P, Aziz Q. · Department of Internal Medicine VI-Psychosomatic Medicine and Psychotherapy, University of Tübingen, Tübingen, Germany. · J Psychosom Res. · Pubmed #18501260 No free full text.

Abstract: From experience, most people know about a link between psychological processes and gastrointestinal sensory and motor functions. Cognitive processes (e.g., attention) as well as affective processes (e.g., fear) play a role in gastrointestinal sensations in healthy controls and patients with irritable bowel syndrome (IBS) alike. However, the exact nature of this relationship has not been completely understood yet. Brain imaging techniques allow for the study of brain-gut interactions in vivo. Accordingly, positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) have been widely used to study neural mechanisms underlying visceral sensations. This article will summarize the results of functional brain imaging studies in healthy controls and selected studies assessing the influence of psychological processes on gastrointestinal functions. Subsequently, this article will deal with those brain areas activated by visceral stimulation in IBS patients. Special attention will be paid to recently published studies concerning psychological factors and novel research questions.

Van Oudenhove L, Coen SJ, Aziz Q. · University Hospital Gasthuisberg, Herestraat 49, B-3000 Leuven, Belgium. · World J Gastroenterol. · Pubmed #17659690 links to  free full text

Abstract: It has since long been known, from everyday experience as well as from animal and human studies, that psychological processes-both affective and cognitive-exert an influence on gastrointestinal sensorimotor function. More specifically, a link between psychological factors and visceral hypersensitivity has been suggested, mainly based on research in functional gastrointestinal disorder patients. However, until recently, the exact nature of this putative relationship remained unclear, mainly due to a lack of non-invasive methods to study the (neurobiological) mechanisms underlying this relationship in non-sleeping humans. As functional brain imaging, introduced in visceral sensory neuroscience some 10 years ago, does provide a method for in vivo study of brain-gut interactions, insight into the neurobiological mechanisms underlying visceral sensation in general and the influence of psychological factors more particularly, has rapidly grown. In this article, an overview of brain imaging evidence on gastrointestinal sensation will be given, with special emphasis on the brain mechanisms underlying the interaction between affective & cognitive processes and visceral sensation. First, the reciprocal neural pathways between the brain and the gut (brain-gut axis) will be briefly outlined, including brain imaging evidence in healthy volunteers. Second, functional brain imaging studies assessing the influence of psychological factors on brain processing of visceral sensation in healthy humans will be discussed in more detail. Finally, brain imaging work investigating differences in brain responses to visceral distension between healthy volunteers and functional gastrointestinal disorder patients will be highlighted.

Anand P, Aziz Q, Willert R, van Oudenhove L. · Peripheral Neuropathy Unit, Department of Clinical Neuroscience, Imperial College London, London, UK. · Neurogastroenterol Motil. · Pubmed #17280584 No free full text.

Abstract: Visceral hypersensitivity (perception of gastrointestinal sensory events at a lower-than-normal threshold) is considered to be an important pathophysiological mechanism in the development of functional gastrointestinal disorders (FGIDs), such as irritable bowel syndrome, non-cardiac chest pain and functional dyspepsia. These disorders are associated with significant health care and socioeconomic costs due to factors such as repeated visits to consultants, hospitalizations and work absenteeism. Despite the presence of extensive evidence linking visceral hypersensitivity and FGIDs, the mechanism(s) underlying visceral hypersensitivity has not been fully elucidated. Suggested hypotheses include sensitization of afferent neurones, both at the level of the enteric and the (afferent) autonomic nervous system (peripheral sensitization), sensitization of spinal cord dorsal horn neurones (central sensitization) and psychosocial factors/psychiatric comorbidity influencing the processing of afferent signals at the level of the brain. Importantly, these hypotheses may be complementary rather than mutually exclusive. However, the degree to which each of these mechanisms contributes to the overall perception of visceral pain, and therefore the generation of symptoms, still remains unclear. This article discusses the mechanisms that may underlie visceral hypersensitivity, with reference to FGIDs. Understanding these mechanisms is essential in order to improve the diagnosis and treatment of patients with these disorders.

Harris ML, Aziz Q. · Department of Gastrointestinal Science, University of Manchester, Salford M6 8HD. · Hosp Med. · Pubmed #12789734 No free full text.

Abstract: Abdominal pain occurs commonly in irritable bowel syndrome. The mechanism of pain is likely to be either peripheral or central sensitization of gut nerves or aberrant brain processing. Functional brain techniques are now allowing the study of brain-gut interactions.

Dunckley P, Aziz Q, Wise RG, Brooks J, Tracey I, Chang L. · Department of Physiology, Anatomy and Genetics, Oxford, UK. · Neurogastroenterol Motil. · Pubmed #17593138 No free full text.

Abstract: A better understanding of the cortical processes underlying attentional modulation of visceral and somatic pain in health are essential for interpretation of future imaging studies of hypervigilance towards bodily sensations which is considered to be an aetiologically important factor in the heightened pain reported by patients with irritable bowel syndrome and fibromyalgia. Twelve healthy subjects were recruited for this study. Simultaneous trains of electrical pulses (delivered to either the rectum or lower abdomen) and auditory tones lasting 6 s were delivered to the subjects during a whole-brain functional scan acquisition. Subjects were instructed to attend to the auditory tones (distracter task) or electrical pulses (pain task). Pain intensity ratings were significantly lower during the distraction task compared with the pain task (P < 0.01) in both sensory modalities. The left primary somatosensory cortex increased in activity with increasing pain report, during attention to visceral pain. Bilateral anterior insula (aIns) cortex activity increased with increasing somatic pain report independent of the direction of attention. Conversely, the primary and secondary auditory cortices significantly increased in activation with decreased pain report. These results suggest that pain intensity perception during attentional modulation is reflected in the primary somatosensory cortex (visceral pain) and aIns cortex activity (somatic pain).

Hobday DI, Hobson A, Furlong PL, Thompson DG, Aziz Q. · Department of Gastroenterology, Hope Hospital, Manchester, UK. · Neurogastroenterol Motil. · Pubmed #11123710 No free full text.

Abstract: Patients with irritable bowel syndrome have heightened perception of gut sensation. The mechanisms responsible for this remain unknown, due to current poor knowledge of the central processing of gut sensation. Cortical evoked potentials (CEPs) have been recorded following both electrical rectal stimulation (ERS) and mechanical rectal stimulation (MRS). Because of the lack of a direct comparison of these two methods, their robustness for future clinical use remains unknown. The aim of our study was to compare the characteristics of CEPs following ERS and MRS. CEPs were recorded from the vertex in 14 healthy volunteers following ERS with bipolar ring electrodes, and MRS by repeated rectal distension. CEPs were recorded in all subjects following electrical stimulation, but only in 11 subjects following mechanical stimulation. In comparison with electrical stimulation, mechanical stimulation produced CEPs with a smaller amplitude and longer latency. However, the morphology of CEPs following electrical and mechanical rectal stimulation was similar, with no difference in the interpeak latencies. In conclusion, we have demonstrated that electrical rectal stimulation is a more reliable stimulus for recording CEPs. The similarity of the morphology and interpeak latencies of the CEPs suggests that both stimuli are activating a similar network of cortical neurones.