Abstracts

RATIONALE: To compare levels of norepinephrine (NE) and epinephrine (EP) in plasma before and after an epileptic seizure.
SUDEP is thought to be the consequence of malignant cardiac arrhythmias. The cardiovascular changes during an epileptic seizure may be related to the activation of peripheral adrenergic neurones and increased catecholamine concentrations in the blood, as reported after drug or electrically induced seizures in animals or electroconvulsive therapy in man. Especially the release of NE in ischemic myocardium during an epileptic fit is assumed to be correlated with the development of serious ventricular arrhythmias.
METHODS: A prospective study involving 23 patients with medically
intractable epilepsy undergoing video-EEG recordings while attending epilepsy surgery investigational procedures between November 1998 and May 2000, at Aarhus University Hospital.
Baseline values of NE and EP were taken the first days after admission at the hospital, at 08.00 A.M. after 24 hour without seizures.
The blood samples were drawn at a median of 15 minutes after a partial epileptic seizure with or without secondary generalization.
RESULTS: Twenty-three patients: 9 women and 14 men were enrolled. The mean age was 42 years (range 20 to 59 years). Four patients were excluded due to either lack of seizures, or daily seizures, or blood collection at a longer time than 30 minutes after seizure cessation.
NE: Samples were analyzed in 19 patients after the first epileptic seizure. The mean baseline value was 1,157 pg/ml. The mean value after first seizure was 2,264pg/ml representing a
significant increase (p=0.003).
In 9 patients samples were analyzed after a second seizure.
The mean value after the seizure no.2 was 3,024 pg/ml, increase which was not statistical significant from baseline (p=0.56).
There was no statistical significant difference between the values obtained after seizure no.1 and no. 2 (p=0.37).
EP: 4 more patients were excluded due to baseline values below the detection limit. Samples from 15 patients were analyzed.
The baseline value was 50 pg/ml. The mean value after first seizure was 131 pg/ml, a significant increase comparing with baseline (p= 0.01). The mean value for the seizure no.2 was 150 pg/ml. The increase in EP between baseline and second seizure was significant (p=0.0001). The increases between seizure no. 1 and no. 2 were not statistical significant (p=0.32).
CONCLUSIONS: NE and EP increased significantly after the
first seizure, demonstrating an important autonomic activation, which may provoke malignant arrhythmias leading to SUDEP.
The increase was significant for EP after second seizure as well. The small variability for the EP, opposite to a larger variability in a small sample for NE can explain why we have not been able to show a significant increase after the second seizure.