Poststroke constipation tied to impaired rectal sensation

Elevated thresholds for rectal sensation, rather than altered anorectal motility, are associated with poststroke constipation, a recent study has shown.

The inclination to constipation of patients with brainstem lesions is potentially due to the disruption of afferent pathway from the rectum to the brain, the authors explained. Additionally, the desire of defecation threshold and physical activity level independently correlate with poststroke constipation.

Seventy-one stroke patients and 24 healthy controls participated in this study. The authors collected general information, clinical characteristics and relevant questionnaires. They performed an anorectal manometry test to assess functions of anorectal motility and rectal sensation, as well as recorded an electrocardiogram to examine autonomic functions.

Constipated patients had increased rectal sensation thresholds compared with those without constipation and healthy controls (p<0.001). There was almost no difference in anorectal motility parameters among the three groups. Constipation-related clinical characteristics, such as spontaneous bowel movements, showed a weak or moderate association with rectal sensation thresholds (p<0.05 to p<0.001 for various parameters).

A higher prevalence of constipation (p=0.045) and first sensation threshold (p=0.025) was observed among patients with vs without brainstem lesions. Moreover, a weak positive association was found between sympathetic activity and stroke severity and a weak negative correlation between vagal activity and stroke severity. Rectal sensation thresholds showed a weak positive association with sympathetic activity and a negative correlation with vagal activity.

Poststroke constipation was independently predicted by the desire of defecation threshold (p=0.043) and physical activity level (p=0.025).

“Constipation is prevalent in individuals after stroke,” the authors noted.