Sensorimotor evaluation of ano-rectal complex in diabetes mellitus

To evaluate the status of ano-rectal complex in diabetic patients, 20 patients with no fecal incontinence and/or local ano-rectal disorders and 18 normal subjects underwent to: 1) ano-rectal manometry; 2) defecography; and 3) rectal sensation tests. In all subjects, the five classic cardiovascular reflexes tests were performed to detect autonomic neuropathy. No significant difference between diabetic patients and controls was found in length, maximum resting pressure and strength of phasic external anal sphincter or anal canal at ano-rectal manometry; similarly, no significant difference between diabetic and normal subjects was found by the same technique in threshold and amplitude of ano-rectal inhibitory reflex. Ano-rectal angle of diabetic patients was not significantly different from normals both at resting and during straining at defecographic study. By rectal sensation testing, it was possible to demonstrate a significant difference between diabetic and normal subjects in perception of rectal distension (87.5 +/- 27.5 vs 39.2 +/- 6.5 ml, p less than 0.05; mean +/- SEM) and of stimulus of defecation (147.0 +/- 56.3 vs 52.9 +/- 18.5 ml, p less than 0.001) but not in perception of maximum tolerable volume (343.5 +/- 69.9 vs 322.0 +/- 48.5 ml, p = NS). No relationship was found between these results and the score of autonomic neuropathy and/or duration of diabetic disease. These data suggest that an early involvement of only sensory parasympathetic fibers of ano-rectal complex occurs in diabetic patients without gastrointestinal symptoms.