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August 20, 1973

Interpretation of Serum Creatine Phosphokinase

JAMA. 1973;225(8):993-994. doi:10.1001/jama.1973.03220360047020

To the Editor.—  The article by Nevins et al (224:1382, 1973) on pitfalls in interpreting serum creatine phosphokinase activity (CPK) and reviewed causes of CPK elevation other than myocardial injury deserves comment. I would like to report a patient with marked elevations of serum creatine phosphokinase levels while he had reversible myopathy and hypokalemia, presumably due to chronic administration of fludrocortisone (Florinef) acetate for severe postural hypotension. This patient's primary diagnosis was "central neurogenic orthostatic hypotension" (Shy-Drager syndrome) and the neurological problem has been reported elsewhere.1

Report of a Case.—  A 63-year-old salesman complained of blurred vision, impotence, and syncope for 20 years. At age 61, he was incapacitated by orthostatic ataxia, hypotension, and tremor and was forced to retire. At age 62, the hypotensive attacks had increased in frequency and severity, and he spent most of his time lying down. The blood pressure ranged from 70/50 to 120/90