Metabolic abnormalities associated with skeletal myopathy in severe anorexia nervosa

The aim of this study was to characterize the metabolic disturbance associa ted with the skeletal myopathy resulting from extreme weight loss in anorex ia nervosa. Muscle function was examined in eight female patients with seve re (40%) weight loss due to anorexia nervosa and histologically confirmed m yopathy. A wide range of biochemical and hematologic investigations were ca rried out, including serum enzymes and the response of plasma lactate to is chemic exercise of forearm muscles. All patients showed proximal muscular w eakness. A diminished lactate response to ischemic exercise was a consisten t finding, and a reduction of serum carnosinase activity was also found. Th ere were no other consistent biochemical or hematologic abnormalities apart from lymphopenia of no clinical consequence. These findings contribute to our understanding of severe protein-energy malnutrition on the musculoskele tal system. The resulting disorder is a metabolic myopathy from which the p atients recover rapidly as their nutrition improves. Although the patients admitted to a variety of abnormal eating behaviors, no correlation was foun d between a specific type of abnormal eating behavior and subsequent bioche mical abnormalities. Reinstating appropriate eating behavior will treat the myopathy. (C) Elsevier Science Inc. 2000.