Is visceral hypersensitivity correlated with symptom severity with IBS

J Pediatr Gastroenterol Nutr. 2008 Mar;46(3):272-8.

Is visceral hypersensitivity correlated with symptom severity in children with functional gastrointestinal disorders?

Castilloux J, Noble A, Faure C. Department of Pediatrics, Division of Pediatric Gastroenterology, Hôpital Sainte-Justine, Université de Montréal, Montréal, Quebec, Canada.

BACKGROUND: Abdominal pain related to irritable bowel syndrome (IBS) and functional abdominal pain (FAP) is frequent in children and can be of variable severity. Both IBS and FAP are associated with rectal hypersensitivity. We hypothesized that in children with IBS and FAP, the rectal sensory threshold for pain (RSTP) is associated with symptom severity.

PATIENTS AND METHODS: A total of 47 patients (34 girls; median age, 14.2 years) with IBS (n = 29) and FAP (n = 18), according to the Rome II criteria, underwent a rectal barostat examination to determine their RSTP. Gastrointestinal symptom severity was assessed by validated questionnaires. During the rectal barostat exam, symptoms were documented using a visual analog scale and by measuring the area coloured on a human body diagram corresponding to painful sensations.

RESULTS: The median RSTP was 16 mmHg and was similar in IBS and FAP patients. Eighty-three percent of the patients had rectal hypersensitivity (RSTP < or = 30.8 mmHg, the 5th percentile of control children studied in our laboratory). Fifty-one percent and 36%, respectively, reported missing school and social activities at least once per week. Increased frequency of pain, missed days of school, missed social activities, and pain during the barostat examination were not associated with lower RSTP values in either the whole group or in the subset of children with rectal hypersensitivity.

CONCLUSIONS: Rectal hypersensitivity is not proportional to the severity of symptoms in children with IBS and FAP, indicating that symptom severity is influenced by other factors in addition to visceral hypersensitivity.