Prospective study of motor, sensory, psychologic, and autonomic functions in patients with irritable bowel syndrome.
OBJECTIVE
The aim of this study was to assess pathophysiology in irritable bowel syndrome (IBS).


METHODS
A total of 122 IBS patients (3 male) and 41 healthy females underwent the following: questionnaires (symptoms, psychology), autonomic function, gut transit, gastric volumes, satiation, rectal compliance, and sensation (thresholds and pain ratings) testing. Proportions of patients with abnormal (<10th and >90th percentiles) motor or sensory functions according to bowel symptoms (constipation [C], diarrhea [D], mixed [M),) pain/bloat, and number of primary symptoms were estimated.


RESULTS
IBS subgroups (C, D, M) were similar in age, gastric and small-bowel transit, satiation, gastric volumes, rectal compliance, sensory thresholds, and pain ratings. IBS was associated with body mass index, somatic symptoms, and anxiety and depression scores. Significant associations were observed with colonic transit (IBS-C [P = .078] and IBS-D [P < .05] at 24 h; IBS-D [P < .01] and IBS-M [P = .056] at 48 h): 32% of IBS patients had abnormal colonic transit: 20.5% at 24 hours and 11.5% at 48 hours. Overall, 20.5% of IBS patients had increased sensation to distensions: hypersensitivity (<10th percentile thresholds) in 7.6%, and hyperalgesia (pain sensation ratings to distension >90th percentile for ratings in health) in 13%. Conversely, 16.5% of IBS patients had reduced rectal sensation. Pain greater than 6 times per year and bloating were not associated significantly with motor, satiation, or sensory functions. Endorsing 1 to 2 or 3 to 4 primary IBS symptoms were associated with abnormal transit and sensation in IBS.


CONCLUSIONS
In tertiary referral (predominantly female) patients with IBS, colonic transit (32%) is the most prevalent physiologic abnormality; 21% had increased and 17% had decreased rectal pain sensations. Comprehensive physiologic assessment may help optimize management in IBS.
Camilleri
Michael
M
Clinical Enteric Neuroscience Translational and Epidemiological Research (CENTER), College of Medicine, Mayo Clinic, Rochester, Minnesota, USA.
McKinzie
Sanna
S
Busciglio
Irene
I
Low
Phillip A
PA
Sweetser
Seth
S
Burton
Duane
D
Baxter
Kari
K
Ryks
Michael
M
Zinsmeister
Alan R
AR
D015746:Abdominal Pain; D000328:Adult; D005260:Female; D005772:Gastrointestinal Transit; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000503:physiopathology* / Q000523:psychology*; D008297:Male; D009043:Motor Activity; D011446:Prospective Studies; D012677:Sensation / Q000502:physiology; D011795:Surveys and Questionnaires