Late epilepsy following open surgery for aneurysmal subarachnoid haemorrhage

To determine the risk for late epilepsy (>2 weeks postoperatively) following aneurysmal subarachnoid haemorrhage (SAH) treated by early aneurysm clipping.

Subgroup analysis of the East Anglian regional audit of SAH (1994-2000; n = 872) with 12 month follow up. Prophylactic anticonvulsants were not routinely prescribed unless there was a perioperative seizure.

472 patients with aneurysmal SAH undergoing surgical clipping of the aneurysm were studied. Patients presenting in WFNS grade V, with space occupying haematomas requiring emergency surgery, or with posterior circulation aneurysms, rebleeds, and surgery after 21 days were excluded.

Late epilepsy occurred in 23 patients (4.9%). There was a correlation between the incidence of late epilepsy and both the presenting WFNS grade (p<0.05) (grade 1, 1.4%; grade 2, 3.8%; grade 3, 9.6%; grade 4, 12.5%) and the Glasgow outcome score at discharge (p<0.01) (good recovery, 2.2%; moderate disability, 5.0%; severe disability, 15.5%). There was no relation between the incidence of late epilepsy and sex or the site of the aneurysm.

The low incidence of late epilepsy following open surgery for aneurysmal SAH supports the withholding of prophylactic anticonvulsants. Patients with poor WFNS grade and poor recovery after surgery are at increased risk and should be closely monitored.