Serum Enzyme Studies in Muscle Disease. Ii. Serum Creatine Kinase Activity in Muscular Dystrophy and in Other Myopathic and Neuropathic Disorders.

It has been established that the levels of certain enzymes are elevated in the serum of patients suffering from muscular dystrophy. Previous studies (Pearson, 1957; Dreyfus, Schapira, and Demos, 1958; Thompson and Vignos, 1959; Schapira, Dreyfus, Schapira, and Demos, 1960; Thomson, Leyburn, and Walton, 1960; Pearson, Chowdhury, Fowler, Jones, and Griffith, 1961) have indicated that a number of different serum enzymes, including aldolase, transaminases, lactate dehydrogenase, and phosphohexoseisomerase, may be found to have abnormally high activity in such cases. Comparative studies in affected patients have shown that the serum creatine kinase is more satisfactory than the other enzymes mentioned above for diagnostic purposes in cases of clinical and preclinical muscular dystrophy, and is also useful in discriminating other forms of dystrophy from the Duchenne type (Chung, Morton, and Peters, 1960; Aebi, Richterich, Colombo, and Rossi, 1962; Dreyfus and Schapira, 1962; Hughes, 1962; Richterich, Rosin, Aebi, and Rossi, 1964). Most recent reports have been confined to relatively small numbers of patients, and deal mainly with the Duchenne variety of muscular dystrophy. Physiological variations in serum creatine kinase activity have recently been described in normal subjects (Pearce, Pennington, and Walton, 1964). Against this background, the present paper gives our findings in a series of patients suffering from the more common varieties of muscular dystrophy and in patients with non-hereditary myopathic disorders, as well as in a number of patients with muscular weakness and wasting of neuropathic origin, in order to delineate more precisely the diagnostic value of serum creatine kinase estimations in these conditions.