Ano-rectal manometry as an evaluating test for impaired ano-rectal function in diabetes mellitus

Diarrhea and/or rectal incontinence may represent a sign of autonomic neuropathy in diabetes. The present investigation was performed to study ano-rectal function and reactivity to appropriate stimuli in 20 diabetic patients with or without autonomic neuropathy (14 insulin-dependent diabetics; 6 non-insulin-dependent diabetics; mean age 39.2 years; mean duration of diabetes 12.6). Twenty-five healthy subjects (mean age 43.5 years) were studied as controls. All subjects underwent ano-rectal manometry by means of special open-ended-tip catheters connected with a 6-channel polygraph. A rectal latex balloon was inflated with 30 or 60 ml air to induce a stimulus which, under normal conditions, is apt to relax the internal sphincter and to contract the external one (ano-rectal inhibitory reflex). Eleven diabetics had symptoms and signs of autonomic neuropathy: 8 of these (73%) showed marked abnormalities of ano-rectal function (i.e. no response even to maximum stimulus or contraction of both sphincters). All non-neuropathic patients showed a normal pattern of ano-rectal manometry. A relationship between abnormal response to rectal stimulation and the presence of autonomic neuropathy involving the pelvic parasympathetic section or regional intramural plexuses may be suspected and demonstrated in diabetic neuropathic patients.