IRRITABLE-BOWEL-SYNDROME - DIFFERENCES BETWEEN PATIENTS WHO SHOW RECTAL SENSITIVITY AND THOSE WHO DO NOT

Objective: To investigate whether measurements of rectal sensitivity m ay be used to segregate patients with irritable bowel syndrome into di fferent treatment categories, intermittent phasic distension of the re ctum was carried out in 55 patients with irritable bowel syndrome and 20 matched normal volunteers. Threshold volumes for sensations were co mpared with anorectal motor responses and symptomatic presentation. Re sults: Of the patients with irritable bowel syndrome, 58% had an abnor mally low threshold for desire to defecate. This group also had abnorm ally low thresholds for sensations of urgency and discomfort, abnormal ly low rectal compliances (P<0.05), and abnormally low threshold volum es for the induction of repetitive rectal contractions and internal an al sphincter relaxation. Values in patients who had a non-sensitive re ctum were normal. The incidence of most symptoms were similar in both irritable bowel syndrome groups though a frequent desire to defecate w as more common in the sensitive group (P<0.01). Anxiety was also more common in the sensitive compared with the non-sensitive group (P<0.05) . Although most sensitive patients had diarrhoea, one-third of patient s with constipation were sensitive and unlike other constipated patien ts, they had a frequent desire to defecate. Conclusion: These results suggest that tests of rectal sensitivity may segregate patients with i rritable bowel syndrome into pathophysiologically distinct subgroups.