Changes in sympathetic and parasympathetic function in alcoholic neuropathy.

We examined sympathetic and parasympathetic function in 17 chronic alcoholics. The subjects were divided into 4 groups; (1) alcoholics without neurologic deficits, (2) alcoholics with mild neuropathy, (3) alcoholics with prominent neuropathy, (4) patients with alcoholic neuropathy but long abstinence. We measured pulsatile arterial pressure (AP) noninvasively and heart rate (HR) was calculated from the AP signals. The sweat response on the palm and sole were measured by ventilated capsular method, while the cutaneous blood flow response by laser Doppler flowmetry. The AP, HR, sweating and cutaneous blood flow response to the Valsalva maneuver were evaluated. In alcoholics with minimal and prominent neuropathy, a pressor (overshooting) in phase IV of the Valsalva maneuver were decreased significantly. The HR response (reflex bradycardia) in phase IV of the Valsalva maneuver was significantly decreased only in alcoholics with prominent neuropathy. The alcoholics with no or minimal neuropathy showed exaggerated sweat responses on the palm and sole. In prominent alcoholic neuropathy, the sweat response was greater on the palm, but diminished on the sole. In no or minimal neuropathy, magnitude of the blood flow response was markedly reduced on both sites. The low resting blood flow levels may contribute to the diminished response. We also evaluated pupillary light reflex and response to methacholine in 7 alcoholics with neuropathy by a portable infrared pupillometer system that can be used with personal computers. Maximum constriction velocity of the pupillary light reflex in patients with alcoholic neuropathy was slower than that in the controls. Reflex amplitude was smaller in the alcoholics than that in the control. However, local administration of methacholine did not change pupillary size and light reflex in the alcoholics same as the controls. The data suggest that preceding sympathetic hyperfunction related with distressed autonomic center is existing with sympathetic hypofunction involved from the sympathetic fibers, target organs and higher center.