Serum creatine kinase elevation in a medical department

Serum creatine kinase (CK) levels are diagnostic markers for acute myocardial infarction. Many other causes however, including neuromuscular disorders, may induce serum CK elevation as well. Aim of the study was to investigate the prevalence of potential causes for serum CK elevation in a medical department. In particular we were interested in the recognition of patients in whom serum CK elevation was due to a neuromuscular disorder. Included in this prospective study were 100 consecutive patients in whom the CK level, determined at admission, was increased (> 70 IU/l in female, > 80 IU/l in male patients). After admission we looked for the presence of causes known to induce CK elevation. Patients with no potential cause for CK elevation were invited for follow-up investigations three months later. If no potential cause could be found and if CK was elevated again on this occasion, the patient was referred for a comprehensive neurological investigation. The prevalence of patients with CK elevation was 11.2%. The 100 patients (44 female, 56 male) were aged from 23 to 94 (mean 67) years. In 95% CK elevation was only up to 500 IU/l. The most frequent cause for serum CK elevation was acute myocardial infarction in 32%. Further frequent causes were drug intake (32%), fall (24%), haematoma (17%), intramuscular injection (16%) and malignancy (11%). In 61% of the cases at least two potential causes for serum CK elevation could be detected. Neuromuscular disorders were found in only 2%. This study shows that serum CK elevation occurs in 11% of patients admitted to a medical department and can be explained by acute myocardial infarction in only 32%. In almost two thirds of the patients, more than one potential cause for serum CK elevation can be found thus making CK elevation a rather unspecific finding. Neuromuscular disorders are rarely found as a cause of serum CK elevation in a medical department.