Faecal incontinence in diabetes mellitus: is it correlated to diabetic autonomic or peripheral neuropathy?

Faecal incontinence is a frequent manifestation of diabetic enteropathy. The purpose of this study was to determine whether faecal incontinence in diabetes mellitus correlates with manifestations of diabetic autonomic or peripheral neuropathy at other organ sites. In 12 incontinent and 15 continent diabetics stool frequency and stool continence, basal and squeeze anal sphincter pressures, and continence to rectally infused isotonic saline solution (1500 ml) were prospectively evaluated. These data were correlated to quantitative measures of autonomic neuropathy as assessed by heart rate variation and pupillary reflex response to light, and to quantitative measures of peripheral neuropathy as assessed by nerve conduction velocity and sensitivity to vibration. Incontinent diabetics exhibited decreased basal and squeeze anal sphincter pressures, and reduced continence for fluid compared to their continent controls. The degree of incontinence correlated well with the maximal volume of retained rectally infused saline solution, but neither with basal and squeeze anal sphincter pressures, nor with the severity of autonomic or peripheral neuropathy at other organ sites. It is concluded that a generalized dysfunction of the autonomic or peripheral nervous system does not play a major role in the pathogenesis of faecal incontinence in diabetes mellitus. The great overlap of basal and squeeze anal sphincter pressures in incontinent and continent diabetics raise evidence for disturbances of additional extrasphincteric factors as part of the pathomechanism of faecal incontinence in diabetes mellitus.