Dysmenorrhoea is associated with hypersensitivity in the sigmoid colon and rectum

Dysmenorrhoea patients experience intense visceral pain during menstruation. Recurrent and/or intense visceral pain can induce facilitation of somatic and visceral nociceptive processing which can lead to viscero-somatic (referred) and viscero-visceral hyperalgesia. Our aim was to study if dysmenorrhoea is associated with hypersensitivity in the referred somatic skin area or in the large bowel, i.e., viscero-visceral hyperalgesia. We measured skin sensitivity in the referred area of the sigmoid colon as well as stimulus–response relationships in the sigmoid colon and rectum. The latter were measured using mechanical (balloon) distension applied via a Barostat in 11 dysmenorrhoea patients without gastro-intestinal complaints and 10 healthy and age matched women, again without gastrointestinal complaints. We found no skin hypersensitivity in the colonic referred area. In contrast, significantly lower distension volumes were seen at each threshold in dysmenorrhoea patients, particularly in the sigmoid colon. The mean reduction in colonic distension volume thresholds for dysmenorrhoea patients vs. controls was 57% at the detection threshold and 39% at the pain threshold. There were no differences in compliance between the groups. These findings suggest that, despite the absence of overt gastro-intestinal symptoms or viscero-somatic sensitisation, dysmenorrhoea patients demonstrate intestinal hypersensitivity. This can be regarded as the result of centrally mediated viscero-visceral hyperalgesia due to recurrent intense menstrual pain.