E. Olafsson et al., Risk of epilepsy in long-term survivors of surgery for aneurysmal subarachnoid hemorrhage: A population-based study in Iceland, EPILEPSIA, 41(9), 2000, pp. 1201-1205
Purpose: Epilepsy is known to result from aneurysmal subarachnoid hemorrhag
e (SAH). There are no population-based estimates of the absolute risk or th
e duration for which this risk is elevated. We have conducted a population-
based study in Iceland of the risk of epilepsy after a ruptured cerebral an
eurysm to address these questions.
Methods: The index patients are all of the patients who presented with SAH
caused by ruptured cerebral aneurysm in Iceland during an Ii-year period (1
958 to 1968) and survived more than 6 months. We determined the number of i
ndex patients who developed epilepsy. The observed number of cases of epile
psy was compared with that expected based on the incidence of epilepsy in I
celand.
Results: There were 44 index patients; 11 (25%) developed epilepsy, all wit
hin 4 years of the insult. Seven (70%) of 10 patients with acute symptomati
c seizures (defined as seizures during the first 2 weeks after the hemorrha
ge) developed epilepsy (relative risk, 7.0; 95% confidence interval, 2.3-21
.6). Epilepsy was more frequent in patients with severe neurological residu
a (48%) compared with patients without (20%) (relative risk, 2.5; 95% confi
dence interval, 0.9-6.3).
Conclusions: The risk for epilepsy among survivors of SAH caused by rupture
d cerebral aneurysm is substantially increased. Both acute symptomatic seiz
ure and persistent neurological impairment are associated with a further in
crease in the risk of epilepsy.