Elevated serum creatine kinase. Following febrile seizures

Serum creatine kinase (CK) was determined in 52 children admitted following an episode of febrile convulsions. Enzyme levels correlated with the estimated duration of the seizure. Twenty-four hour values were significantly higher than those observed 1 hour after the convulsive episode. Serum CK levels are frequently used for diagnostic purposes, so the questionable validity of this test when drawn after a convulsive episode must be considered.