Seizure or syncope: the diagnostic value of serum creatine kinase and myoglobin levels

OBJECTIVE: To determine if the serum levels of creatine kinase and myoglobin can be used to differentiate the grandmal tonic-clonic seizure and syncope activities in the emergency department (ED). METHODS: Consecutive patients over 16 years old who presented to an ED of a tertiary care hospital with a witnessed tonic-clonic seizure activity and a history of a transient loss of consciousness with normal neurological exams in the ED were selected to either seizure or syncope groups. Patients with an unclear history of seizure or syncope with more than 4 h of the activity and with any conditions that could elevate creatine kinase and myoglobin levels were excluded. Serum samples were drawn at presentation and at the fourth hour of the event. RESULTS: Thirty-seven syncope and 26 generalized tonic-clonic seizure patients with a definite history were assigned to study groups. There was not a statistically significant difference in the time of drawing of the first serum sample among groups. No statistically significant differences were determined with the first samples of creatine kinase and myoglobin for both groups. Serum levels of creatine kinase drawn at the fourth hour of the activity were significantly higher in favor of the seizure group. However, myoglobin levels were insignificant at the fourth hour. CONCLUSION: Serum creatine kinase measured at the fourth hour of loss of consciousness may be a potentially useful laboratory test to differentiate tonic-clonic seizure from syncope. Patently, it requires and warrants further study.