Post-Stroke Epilepsy

Post-stroke epilepsy is recurrent unprovoked seizures after stroke. Early seizures (within 7 days) are acute symptomatic and occur in 2 to 4% of ischaemic and 10 to 16% of haemorrhagic strokes. Late seizures (after 7 days) are unprovoked, and 30 to 40% recur. Stroke causes about 10 to 15% of epilepsy in adults, and 50% of epilepsy that starts after age 65.

Risk factors include cortical involvement, large infarct, haemorrhagic stroke, early seizures, younger age and severe stroke.

Pathophysiology. Early seizures result from ischaemic and metabolic injury, and late seizures result from gliosis, haemosiderin deposition and network reorganisation.

Focal seizures (motor, sensory, impaired awareness) with or without secondary generalisation, status epilepticus (in 10%), and sometimes unrecognised non-convulsive seizures presenting as confusion, transient aphasia or fluctuating deficit.

Red flags.

• Status epilepticus.
• New fluctuating confusion after stroke.

Clinical diagnosis, with EEG (focal slowing, epileptiform discharges, periodic discharges) when seizures are uncertain. Brain imaging (CT or MRI) shows the stroke and excludes new events or haemorrhage. Check glucose, sodium, calcium, renal function and drugs (such as tramadol, antibiotics, bupropion). Exclude recurrent stroke and transient ischaemic attack.

Differential diagnosis.

• Transient ischaemic attack and recurrent stroke.
• Syncope, limb shaking transient ischaemic attack and migraine aura.
• Delirium and metabolic encephalopathy.

No primary prophylaxis. Do not give antiseizure drugs after stroke to prevent seizures.

After a first unprovoked (late) seizure. Treatment is reasonable because of the high recurrence risk (over 60%). Lamotrigine 25 mg daily for 2 weeks, then 50 mg daily for 2 weeks, then increased to 100 to 200 mg daily, or levetiracetam 250 to 500 mg twice daily, increased to 1000 to 1500 mg twice daily (adjust to eGFR; monitor mood), are preferred in older adults. Low dose therapy is often effective. Avoid enzyme inducing drugs (carbamazepine, phenytoin) because of interactions with anticoagulants and statins, and effects on bone and vascular risk.

Acute symptomatic seizure. Treat the seizure, and stop treatment after the acute period if seizures do not recur (3 to 6 months).

Status epilepticus. Lorazepam 4 mg IV, then levetiracetam 60 mg/kg IV (maximum 4500 mg) or valproate 40 mg/kg IV.

Stroke prevention. Continue secondary prevention (antiplatelets or anticoagulants, statins, blood pressure control).

Driving and safety. Advise about local licensing rules.

Monitoring. Seizure frequency, mood, cognition, bone health and drug adverse effects. Review the need for drugs after 2 years seizure free.

Referral and escalation. Refer to neurology if seizures persist.

Special groups. In older adults, start low and titrate slowly and watch falls and sedation.