SIGNIFICANCE OF TYPE-II FIBER ATROPHY IN CHRONIC-ALCOHOLIC MYOPATHY

To determine the significance of type II fiber atrophy in alcoholic my opathy and its relationship with ethanol-related diseases a prospectiv e study was carried out in 100 chronic alcoholics who showed clinical suspicion of skeletal myopathy. Measurement of muscle strength, labora tory analysis, nutritional assessment and open biopsy of deltoid muscl e were performed in each case, as well as electrophysiological testing for peripheral neuropathy. Hepatic ultrasonography and liver biopsy, echocardiography and radionuclide cardiac scanning were carried out in selected subjects. According to histomorphometric analysis, type II f iber atrophy was found in 33 cases (33%), being selective for type II B fiber in 23 (70%). Skeletal myopathy was diagnosed in 61 cases, alco holic cardiomyopathy in 26, peripheral neuropathy in 23 and cirrhosis in 12. Patients with type II fiber atrophy had a significantly higher total lifetime dose of ethanol, presented a greater incidence of skele tal myopathy and peripheral neuropathy, and exhibited significantly lo wer values of percentage of ideal body weight and lean body mass than their counterparts. However, the only independent factors for developi ng type II fiber atrophy were the coexistence of caloric malnutrition (p = 0.004) and the presence of skeletal myopathy (p = 0.043). Selecti ve type II fiber atrophy is a non-specific finding in alcohol-induced muscle damage appearing, overall, in the patients with caloric malnutr ition as well as in those with histologic evidence of myopathy.