High creatine kinase-muscle brain levels greatly exceeding total creatine kinase levels in a 2-month-old infant

Abstract

The measurement of creatine kinase muscle brain (CK-MB) by the method of immunoinhibition has various drawbacks, which are posing as a hindrance in its role as a sensitive diagnostic indicator. A 2-month-old infant presented with symptoms of difficulty in breathing and cough. A chest X-ray done showed an incidental finding of a cardiac anomaly, and ultrasonography cranium showed a well-defined cystic lesion seen in the frontal horn of the bilateral lateral ventricle and signs of a resolving hemorrhage. The CK-MB level (761U/L) was greatly exceeding the CK levels (427U/L). This raise in CK-MB may be due to the presence of CK-BB or macro-CK in the plasma. Electrophoresis of the CK enzyme is, therefore, the best way to resolve the shortcomings of immunoinhibition. Macro-CK and CK-BB should hence also be kept in mind when the physician makes a diagnosis on the basis of such a laboratory report.

Keywords

• atypical creatine kinase
• creatine kinase-bb
• creatine kinase-muscle brain
• immunoinhibitionmethod
• macro creatine kinase