Diabetic autonomic neuropathy: exploration methods and principles

Diabetic autonomic neuropathy (DAN) has a prevalence of 30% in the diabetes mellitus, whether it is of type 1 or 2. It is one of the major risk factors in cardiovascular mortality. There are many clinical symptoms. Cardiovascular symptoms are orthostatic hypotension, resting tachycardia and even silent myocardial infarction. Digestive symptoms include gastroparesis, diarrhoea and anorectal disorders. Erectile dysfunction and urinary disorders also occur frequently. Methods of assessing DAN are simple, but require strict technical conditions. They include cardiovascular tests, which measure the response of arterial tension and heart rate response to codified stimulations, enabling the diagnosis of cardiac autonomic neuropathy (CAN). A battery of four or five tests is recommended for the diagnosis of DAN. In first intention, the heart rate response to deep breathing and heart rate response to standing are recommended. If one of these two tests is abnormal, or for patients with high cardiovascular risk, it is recommended to carry out these two tests plus a tilt test, a Valsalva maneuver and the hand grip test. If one of the tests is abnormal, development of CAN should be suspected; if two tests are abnormal, diagnosis of CAN is confirmed. These tests must be repeated annually, in order to detect and treat CAN. Optimal therapeutic management of glycemia and other cardiovascular risk factors decreases the risk of DAN and in confirmed cases of DAN such management reduces the risk of complications and mortality.