What is the best approach to manage seizures in a neurosurgical patient?

Management of Seizures in Neurosurgical Patients

Administer anticonvulsants only to neurosurgical patients who have already experienced seizures or are undergoing active surgery—prophylactic anticonvulsants should not be given to patients without seizure history, as they do not reduce first seizure risk and offer no benefit. 1

Key Decision Point: Has the Patient Already Seized?

For Patients WITH Prior Seizures (Secondary Prophylaxis Required)

Levetiracetam is the first-line agent at 1000-2000 mg/day divided twice daily due to superior tolerability, lack of drug interactions with steroids and chemotherapy, and minimal cytochrome P450 effects. 2, 1

• Start with 1000-1500 mg IV loading dose, then transition to oral maintenance dosing at the same total daily dose divided twice daily 3, 4
• Levetiracetam achieved ≥50% seizure reduction in 91.7% of post-operative brain tumor patients in prospective studies 3
• In supratentorial neurosurgery patients specifically, levetiracetam demonstrated significantly lower seizure rates (0.70 events per patient-year) compared to other anticonvulsants (2.20 events per patient-year) 5

If levetiracetam monotherapy fails, add lacosamide as adjunctive therapy for focal seizures with favorable side-effect profile 2

For Patients WITHOUT Prior Seizures (Prophylaxis NOT Indicated)

Do not administer prophylactic anticonvulsants to neurosurgical patients who have never seized, as meta-analyses demonstrate no reduction in first seizure risk at 6 months and no benefit in the first 14 days post-operatively. 1

Exception: Perioperative period only (during and immediately after surgery):

• Anticonvulsants may be administered during the surgical procedure itself 1
• Strongly consider discontinuation within 7 days post-operatively if the patient remains seizure-free, as continuation beyond this period provides no additional benefit 1

High-Risk Features Requiring Clinical Judgment

While prophylaxis is generally not indicated, consider short-term perioperative anticonvulsants (≤7 days) in patients with multiple high-risk features: 1

• Ruptured middle cerebral artery aneurysm
• High-grade subarachnoid hemorrhage
• Intracerebral hemorrhage
• Hydrocephalus
• Cortical infarction
• Supratentorial location with significant mass effect

Even in these cases, discontinue after 7 days if no seizures occur, as longer prophylaxis does not reduce future seizure risk. 1

Agents to Avoid

Never use phenytoin in neurosurgical patients—it is associated with excess morbidity and mortality, poorer cognitive outcomes, potential interference with nimodipine metabolism, and requires serum monitoring. 1, 2, 1

Avoid enzyme-inducing anticonvulsants (phenobarbital, carbamazepine) as they significantly impair metabolism of chemotherapy agents, steroids, and other medications commonly used in neurosurgical patients. 1, 2

Do not use valproic acid in females of childbearing potential, and recognize it requires regular monitoring for drug interactions and carries risks of thrombocytopenia and hepatotoxicity. 1, 2

Benzodiazepines (clobazam, clonazepam) are not appropriate for chronic seizure management in post-craniotomy patients—they are intended for acute seizure control or specific refractory epilepsy syndromes, not long-term maintenance. 2

Duration of Treatment

For patients who seized and received anticonvulsants:

• Continue treatment until achieving both surgical success (near-total resection) AND prolonged seizure freedom (typically 1-2 years minimum) 2
• If only partial resection was performed, continue anticonvulsants until local control is achieved and extended seizure-free period is documented 2
• Taper gradually when discontinuing to avoid withdrawal-precipitated seizures 6

Acute Seizure Management (Status Epilepticus)

If active seizures occur:

• Administer IV benzodiazepine (diazepam) first for immediate seizure control 6
• Follow with levetiracetam 1000-4000 mg IV if seizures persist after benzodiazepine 7
• IV levetiracetam terminated status epilepticus in 76.6% of patients in prospective studies 7
• Phenytoin can be used for status epilepticus at 10-15 mg/kg IV (maximum rate 50 mg/min in adults) with continuous cardiac monitoring, but only when levetiracetam is unavailable or contraindicated 6

Critical Pitfall: New or Worsening Seizures

Obtain immediate repeat neuroimaging (contrast-enhanced MRI or CT) when seizures develop or worsen post-operatively, as this often signals complications including: 2

• Hematoma expansion
• Infection/abscess formation
• Cerebral edema progression
• Tumor recurrence or progression
• Hydrocephalus

Do not simply increase anticonvulsant dosing without excluding structural complications.

Concurrent Management of Cerebral Edema

Administer dexamethasone 4-8 mg/day (up to 16 mg/day in divided doses for significant edema) to reduce perilesional vasogenic edema that can lower seizure threshold. 1

• Taper steroids as quickly as clinically feasible (ideally within 3 weeks) to avoid complications including personality changes, immunosuppression, metabolic derangements, and impaired wound healing 1
• For patients with incidentally discovered lesions without mass effect, steroids may be withheld entirely 1

Monitoring Strategy

Check trough levels just prior to next scheduled dose to assess therapeutic range (10-20 mcg/mL for phenytoin if used; levetiracetam does not require routine level monitoring). 6

Monitor for common levetiracetam adverse effects (occurring in ~6-8% of patients): somnolence, behavioral changes/reactive psychosis, headache, nausea—these typically resolve with dose reduction. 3, 4, 5