seizure vs. syncope: is creatine kinase (CK) useful?

STUDY 1:
--37 syncope and 26 generalized tonic–clonic seizure patients
--tested serum CK and myoglobin at ED presentation and 4 hrs after the event

--no statistically significant different in myoglobin at any time
--no statistically significant different in CK at ED presentation
--CK drawn 4 hrs after the event:

• elevated in four of 37 (10.8%) patients with syncope
• elevated in nine of 26 (34.6%) patients with seizure activity
• statistically significant difference in CK between seizure and syncope groups (P<0.05)
• sensitivity 34%
• specificity 89%

STUDY 2:
--Sequential sample of 205 patients with transient loss of consciousness. The study group consisted of 96 patients who had CK measurements in the ED

--Mean (+/- SE) CK significantly higher in the seizure group (231.1 +/- 34.8 U/L vs. 70.5 +/- 5.6 U/L, p less than 0.001).
--elevated CK: sensitivity of 0.43, specificity of 0.98--elevated CK >3hrs after event: sensitivity was 0.80, specificity was 0.94


10-SECOND TAKEAWAY:
--serum CK level after seizure: not too sensitive (better after 3 hrs), pretty specific
--may be useful to confirm suspected seizure if elevated >3-4 hours s/p event


Reference(s): study 1, study 2, picture