McArdle's syndrome: the reaction to a fat-rich diet
Viskoper, R.J.; Wolf, E.; Chaco, J.; Katz, R.; Chowers, I.
American Journal of the Medical Sciences 269(2): 217-221
1975
ISSN/ISBN: 0002-9629 PMID: 1056701 Document Number: 96222
McArdle's syndrome is thought to be caused by absence of phosphorylase in skeletal muscle, which results in defective glycogen breakdown. A young man with the typical symptoms of low tolerance to physical activity, muscle fatigue and severe cramps during work, which led to myoglobinuria, is described. Muscle phosphorylase was absent. The effect of fat-rich diet on muscle performance was observed on 3 occasions. Ergometric exercises continued until severe fatigue occurred. Blood pressure and ECG were recorded and blood was sampled before and after exercise for the estimation of triglyceride, free fatty acids (FFA) and lactic acid. After 3 days of normal diet, FFA, lactic acid and triglyceride in serum before exertion were 400 m-equiv/litre, 220 mg/100 ml and 261 mg/100 ml, respectively, and did not increase after 21/2 min, when the test was discontinued. After 3 days on a fat-rich diet, serum FFA at rest were 720 m-equiv/litre, but rose to 1200 after exercise; triglyceride rose from 245 to 350 mg/100 ml. Performance did not improve, but the subject felt fitter, recovery was quicker and discomfort did not persist; the improvement was maintained after 2 weeks at home.