[Comparative value of anorectal manometry and electrocardiography in the diagnosis of diabetic autonomic neuropathy].

Searching for silent anorectal autonomic neuropathy, we investigated the anorectal sensorimotor function in 79 continent diabetics. Thirty four per cent of the patients had a basal anal sphincter pressure lower than 40 mm Hg N = 54.5 +/- 15.5 mm Hg and 11 p. 100 had a threshold of conscious rectal sensation higher than 20 ml (N less than or equal to 20 ml). An electrocardiogram was performed and the change in heart rate resulting from successive deep breaths was recorded for each patient. Cardiac autonomic neuropathy was diagnosed when cardiac frequency did not change with ventilation. This was reflected by a ratio E/I (largest RR space during expiration on the electrocardiogram to the shortest during inspiration) close to one. Compared to cardiac criteria for autonomic neuropathy, the sensitivity of anorectal manometry in the detection of diabetic autonomic neuropathy was 77.2 p. 100 and specificity was 82 p. 100. Low basal anal sphincter pressure in asymptomatic diabetics seems to be a sensitive and specific criteria for the assessment of diabetic autonomic neuropathy and correlates closely with cardiac criteria.