Altered rectal perception in irritable bowel syndrome is associated with symptom severity

Diverging results exist regarding the connection between altered visceral perception and gastrointestinal (GI) symptoms, as well as the effects of psychological status on visceral sensitivity. We sought to investigate different aspects of rectal perception in irritable bowel syndrome (IBS) and the association with GI and psychological symptoms.

We included 109 patients with IBS meeting Rome II criteria (77 women; age range, 20-71 years) and 29 healthy controls (21 women; age range, 20-68 years). They underwent rectal balloon distentions determining sensory thresholds for discomfort and pain, the perceived intensity of unpleasantness, and the viscerosomatic referral area. The fifth percentile (thresholds) and 95th percentile (unpleasantness and referral area) in controls were used to define altered perception. Questionnaires were used to assess severity of IBS-related GI symptoms and psychological symptoms.

When combining the 3 aspects of perception, 67 patients (61%) had altered rectal perception. These patients, compared with normosensitive patients, more frequently reported moderate or severe pain (73% vs 44%; P < .01), bloating (73% vs 36%; P < .0001), diarrhea (47% vs 21%; P < .01), satiety (39% vs 13%; P < .01), and clinically significant anxiety (31% vs 12%; P < .05). In a multivariate analysis, only pain and bloating remained associated with altered rectal perception.

Altered rectal perception is common in IBS and seems to be one important pathophysiologic factor associated with GI symptom severity in general and pain and bloating in particular. It is not just a reflection of the psychological state of the patient.