Large and small fiber neuropathy in chronic alcohol-dependent subjects

The aim of the present study was to evaluate the occurrence of large and small fiber neuropathy among alcohol-dependent subjects and to correlate neuropathy with the pattern of alcohol abuse, age of the subjects, nutritional status, and biochemical parameters. The study sample comprised 98 consecutive alcohol-dependent subjects without signs of malnutrition treated for detoxification voluntarily in the specialized unit of the Athens University Psychiatric Clinic in an inpatient basis. Polyneuropathy (PN) was graded using the neuropathy symptoms score and neurologic disability score, conduction velocity studies, and quantitative sensory tests. Seventy-seven men and 21 women aged 27-70 years took part in the study. PN was diagnosed in 57 subjects (58.2%). PN of both large and small fibers was found in 25 patients (25.5%); exclusively small fiber neuropathy was observed in 12 (12.2%) and exclusively large fiber neuropathy in 20 patients (20.4%). Neuropathy was significantly correlated with the age of the subjects, duration of alcohol abuse, liver dysfunction, macrocytosis, and blood sugar levels upon admission. PN was significantly more frequent in males than in females. The two groups of exclusively large and exclusively small fiber neuropathy did not differ significantly in any clinical and laboratory parameter. Subclinical neuropathy (stage 1) was observed in 11.2%, which also did not differ significantly in any clinical and laboratory parameter from the stage 2 PN group subjects. Our findings indicate the direct toxic effect of alcohol on peripheral nerve fibers as the main etiologic factor of alcoholic PN. Long-standing hyperglycemia may be another contributing factor. Impaired vitamin B(12) utilization may be also involved.