Transformed migraine exacts a significantly higher economic toll on patients and health care systems compared with other forms of migraine. Our findings support the need to prevent migraine progression and to provide appropriate management and treatment of transformed migraine.
IBS patients show altered brain responses to rectal stimuli, regardless of whether these stimuli are actually delivered or simply anticipated. These alterations are consistent with reported alterations in autonomic and perceptual responses and may be related to altered central noradrenergic modulation.
Background and aims-Visceral hyperalgesia has been implicated as a factor contributing to symptom generation in irritable bowel syndrome (IBS). However, previous studies using intestinal balloon distension have used psychophysical procedures which do not provide adequate and unbiased measures of visceral sensitivity. Methods-Three psychophysical tasks were examined in 45 patients with IBS (positive Rome criteria) and 14 controls using rectal balloon distension with a computerised distension device. Discomfort threshold and tolerance were assessed during an ascending series of phasic pressure stimuli and during an interactive threshold tracking procedure. In addition, stimulus response functions were generated from intensity and unpleasantness ratings of the rectal distensions. Results-Discomfort threshold and tolerance for the ascending stimuli were significantly lower for the patients with IBS compared with the controls. In contrast, discomfort thresholds during the tracking procedure and stimulus response curves for the ascending series were not diVerent between the groups. A factor analysis of the psychophysical data was consistent with the presence of two distinct and unrelated perceptual alterations related to rectal distension: hypervigilance for visceral stimuli, manifested as lowered response criteria for using the descriptor "discomfort"; and rectal hypersensitivity, manifested as a lower discomfort threshold and left shift of the stimulus response curves. Conclusions-Patients with IBS as a group have a greater propensity to label visceral sensations negatively and show a lower tolerance for rectal balloon distension. A subgroup of patients also have baseline rectal hypersensitivity, assessed by unbiased measures of discomfort threshold and stimulus intensity judgements. (Gut 1997; 41: 505-512) Keywords: irritable bowel syndrome; visceral hypersensitivity; pain threshold A variety of clinical observations including the presence of recurring abdominal pain, and excessive pain during endoscopic examinations of the sigmoid colon are consistent with a role for visceral hyperalgesia in irritable bowel syndrome (IBS) symptom generation. Experimental evidence from studies assessing visceral sensitivity demonstrates that a variety of perceptual abnormalities in relation to gastrointestinal stimuli are more frequent in patients with IBS.1-3 For example, in a recent study, Mertz et al 3 found that patients with IBS had a significantly lower median discomfort threshold for a 30 second rectal balloon stimulus compared with a normal population. If lowered threshold and two other perceptual abnormalities were considered (altered area of sensory referral and increased ratings of the rectal sensations from balloon distension), 95% of patients with IBS had at least one abnormality. Only 7% of a control population had at least one of the three sensory findings. Other studies have also found significant perceptual alterations in IBS populations including lowered discomfort thresholds for balloon distension of t...
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