COLD PRESSER TEST IN DIABETIC AUTONOMIC NEUROPATHY

The tests for evaluating sympathetic dysfunction seen in diabetic pati ents are few and insensitive. For this reason, there are some difficul ties in diagnosing sympathetic dysfunction and additional tests are re quired. The cold presser test causes a strong sympathetic stimulus and this study investigated whether this test could be helpful in diagnos ing sympathetic dysfunction. The cold presser test was applied to a gr oup of diabetic patients (n = 33) and a control group (n = 15), The me an systolic cold presser response in diabetic patients was found simil ar to controls (9 +/- 1.4 vs. 10.6 +/- 1.2 mmHg). However the mean dia stolic cold presser response was significantly lower in diabetic patie nts as compared with the control group (7.7 +/- 1.0 vs. 12.0 +/- 1.1 m mHg, P < 0.05). Cardiovascular reflex tests were also applied to diabe tic patients and deep breathing and orthostatic hypotension test resul ts were used to categorize the patients with parasympathetic and/or sy mpathetic dysfunction, In patients with autonomic neuropathy the diast olic cold presser response was smaller than the controls (6.9 +/- 1.3 vs. 12.0 +/- 1.1 mmHg, P < 0.05); however, in patients without autonom ic neuropathy it was not significantly different from controls (8.7 +/ - 1.8 vs. 12.0 +/- 1.1). The systolic cold presser test results showed no difference between patients with or without parasympathetic dysfun ction but diastolic cold presser results in patients with sympathetic dysfunction were significantly lower than the results of the patients without sympathetic dysfunction (3.8 +/- 1.3 vs. 9.1 +/- 1.3 mmHg, P < 0.05). During the test, increases in heart rate are similar between d iabetic patients and controls (4.7 +/- 0.9 vs. 6.6 +/- 1.4). By analyz ing these data, it has been concluded that the diastolic cold presser response was disturbed in diabetic patients; this was related to sympa thetic dysfunction and the cold presser test could be used to diagnose diabetic sympathetic dysfunction at the bedside. Moreover, when the h eart rate and blood pressure responses in the test were evaluated toge ther, it has been suggested that the alpha adrenergic system could be more affected than the beta adrenergic system in diabetic autonomic ne uropathy.