Creatine kinase isoenzymes in high-risk infants

Abstract

Serial measurements of serum creatine kinase isoenzymes were done from birth to 15 days of age in healthy premature infants, infants with perinatal or neonatal asphyxia and infants without asphyxia but with miscellaneous problems. Serum brain-specific fraction of creatine kinase (CK-BB) activity was higher in cord than in maternal serum (P < 0.01). In healthy infants, the serum activity of heart- and muscle-specific fractions of creatine kinase increased after birth, reached a plateau between 12 and 48 hr, and then declined, whereas the serum CK-BB decreased rapidly after birth and remained stable between 6 hr and IS days. Compared to controls, infants with severe asphyxia and neurologic damage had a significant rise in serum CK-BB (P < 0.001). When the peak CK-BB level exceeded 35 IU/liter the mortality was high (83%). The increase in CK-BB was not observed in infants who received pentobarbital shortly after the episode of asphyxia. Diseases of the lung, kidneys, gastrointestinal tract, and abruptio placentae were not associated with increases of serum creatine kinase isoenzymes. Speculation: The rise in serum brain-specific fraction of creatine kinase (CK- BB) reached maximal levels 5 to 15 hr after the asphyxia! insult; thus, the finding of a very high CK-BB activity in cord serum would imply intrauterine asphyxia taking place several hr before delivery, and cord CK-BB determinations could be useful for the evaluation of fetal distress. Correlation of neonatal CK-BB levels with long-term neurologic outcome would determine whether CK- BB can be used for the early prediction of the extent of neurologic damage following neonatal asphyxia. CK-BB activity determinations might also be useful in assessing the efficacy of therapeutic maneuvers aimed at preventing or minimizing hypoxic-ischemic central nervous system insults. © 1980 International Pediatric Research Foundation, Inc.