Acute symptomatic seizures

Definitions

• Seizures occurring:

o At the time of a systemic insult OR

o In close temporal relationship to an acute brain insult

- Within 7 days of stroke, TBI, anoxic encephalopathy, intracranial surgery

- First identification of subdural haemorrhage

- During presence of active infection

- During active phase of MS relapse or autoimmune disease

- Within 24 hours of metabolic derangements including

• drug and alcohol withdrawal

• seizure provoking medications

ILAE proposed cut-offs for metabolic derangements causing seizures

• Glucose <2 or >25

• Sodium <115

• Calcium <1.2

• Magnesium <0.3

• Creatinine >884umol/L

Epidemiology

• 40% of patients with seizures

• 50-70% of status epilepticus episodes

• Lifetime risk Male vs female – 5% vs 2.7%

• In an 80yo person the lifetime risk of acute symptomatic seizures in 3.6%

• Highest incidence in first year of life and then in the elderly

• High risk of mortality in first 30 days (up to 20%) – this is 8.9x higher than after unprovoked seizure

o The increased mortality is related to underlying conditions

Stroke

After matching for stroke severity etc worse outsomes if seizures ocure – mortality (27% vs 14%) and mRS worse

Risk of recurrence

• Overall 18.7% risk of seizure recurrence, however a single figure is not useful, given significant variation depending on aetiology (see graph below).

• Prediction of risk

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Treatment:

Treatment can be at different times for different reasons

• Primary prevention prior to insult (i.e before neuro-surgery)

• Prophylactic during actue insult to prevent acute seizures

• Prophyactic during acute phase to prevent long term epilepsy

• Post acute seizure to prevent recurrence

Primary prevention evidence

· Reduced acute symptomatic seizures, but does not reduce late seizures/remote symptomatic epilepsy

· In stroke limited studies, no clear benefit

· Some evidence of poorer rehabilitation outcomes in patients treated with ASM, effect also present with newer ASM