Symptoms and visceral perception in patients with pain-predominant irritable bowel syndrome

Abdominal pain is thought to be a hallmark of the irritable bowel syndrome (IBS), although currently used symptom criteria do not differentiate between abdominal pain and discomfort. By focusing on viscerosensory symptoms, we sought to determine: 1) which type of symptoms are most commonly reported by IBS patients, and 2) whether patients who report pain as their most bothersome symptom differ in clinical, psychological, and physiological characteristics.

A total of 443 consecutive new patient referrals to a tertiary referral center for functional gastrointestinal disorders who met symptom criteria for IBS were given validated, psychometric, health status, and bowel symptom questionnaires containing specific questions regarding the patients' predominant viscerosensory gastrointestinal symptom. Of these patients, 155 (35%) also met criteria for functional dyspepsia. A representative subset of the total IBS patient population (n = 58) underwent evaluation of perceptual responses to controlled rectal distension before and after a noxious sigmoid conditioning stimulus.

Viscerosensory symptoms clustered into four groups: 1) abdominal pain, 2) bloating-type discomfort, 3) sensation of incomplete rectal evacuation, and 4) extraabdominal (chest pain or pressure and nausea). A total of 66% of patients reported gas as one of their viscerosensory symptoms, whereas 60% reported abdominal pain as one of their symptoms. Only 29% rated abdominal pain as their most bothersome symptom, whereas bloating-type symptoms were listed by 60% as most bothersome. Although pain predominance did not correlate with the severity of gastrointestinal or psychological symptoms, there was a significant correlation with the development of rectal hypersensitivity in response to the sigmoid conditioning stimulus.

In a tertiary referral population of IBS patients: 1) abdominal pain is reported by only one third of patients as their most bothersome viscerosensory symptoms; and 2) pain-predominance correlates with development of rectal hypersensitivity after a noxious sigmoid stimulus.