Diagnosis and Management of Postoperative Seizures
Diagnostic Approach
When a postoperative seizure occurs, immediately obtain repeat neuroimaging (contrast-enhanced MRI or CT) to exclude structural complications such as hematoma, infection, or other acute changes, as new or worsening seizures often signal these complications. 1
Key Diagnostic Considerations
Distinguish from postoperative delirium: Postoperative delirium meets DSM-5 criteria and occurs within 1 week post-procedure, characterized by acute confusion and altered consciousness rather than the stereotyped motor manifestations of seizures. 2
Timing matters for etiology: Early postoperative seizures (within 24 hours) are most commonly associated with inadequate anticonvulsant prophylaxis in patients with pre-existing risk factors, not typically due to hematoma or metabolic abnormalities. 3, 4
Evaluate for predisposing factors: Frontal or temporal lobe surgery, prior seizure history, and inadequate preoperative anticonvulsant levels are the strongest predictors of early postoperative seizures. 3, 4
Consider medication-induced seizures: In cardiac surgery patients, tranexamic acid is a strong independent predictor of postoperative seizures (OR 14.3), particularly at doses exceeding 80 mg/kg. 5
Clinical Assessment
Document seizure characteristics: Record whether seizures are generalized or focal, their duration, and whether they resemble any preoperative seizure pattern. 3, 6
Check anticonvulsant levels: If the patient was on preoperative anticonvulsants, verify therapeutic levels were achieved, as inadequate prophylaxis is the most common modifiable factor. 3, 4
Quantify seizure burden: Patients with >5 acute postoperative seizures have significantly worse outcomes, including longer hospitalizations, worse long-term seizure control, and higher reoperation rates compared to those with 0-5 seizures. 6
Treatment Approach
Levetiracetam is the preferred first-line anticonvulsant for postoperative seizures at 1000-2000 mg/day divided twice daily, based on superior tolerability and lack of drug interactions with steroids and other perioperative medications. 1
First-Line Management
Initiate levetiracetam immediately: This has become the drug of first choice at most neurosurgical centers due to efficacy, good tolerability, and minimal cytochrome P450 interactions. 1, 7
Avoid benzodiazepines for maintenance: Clobazam and clonazepam are not appropriate for chronic seizure management in postoperative patients; they are intended for acute seizure control or specific refractory epilepsy syndromes, not long-term maintenance therapy. 1
Do not use enzyme-inducing anticonvulsants: Phenytoin, phenobarbital, and carbamazepine should be avoided as first-choice agents due to unfavorable side-effect profiles, significant drug interactions with steroids and cytotoxic agents, and requirement for serum level monitoring. 1, 7
Alternative and Adjunctive Options
Consider lacosamide as add-on therapy: If monotherapy with levetiracetam fails to control seizures, lacosamide can be added as adjunctive therapy for focal seizures with a favorable side-effect profile. 1, 7
Lamotrigine as alternative: This is effective but requires several weeks of gradual titration to reach therapeutic levels, making it less ideal for acute management. 7
Phenytoin remains FDA-approved: While phenytoin is indicated for "prevention and treatment of seizures occurring during or following neurosurgery," 8 modern guidelines favor levetiracetam due to better tolerability and fewer interactions. 1, 7
Special Populations
Pediatric cardiac surgery patients: Perioperative seizures are more common with deep hypothermic circulatory arrest (DHCA) and are the medical variable most consistently related to adverse neurodevelopmental outcomes at 16 years of age. 2
Brain tumor patients: Those who have already experienced seizures require secondary prophylaxis (not primary prophylaxis) and should be treated with levetiracetam as first-line. 1, 7
Duration of Treatment
Continue until surgical success and seizure freedom: Consider tapering anticonvulsants only after achieving both surgical success and prolonged seizure freedom (typically 1-2 years minimum) for patients with near-total resection. 1, 7
Extend treatment after partial resection: If only partial resection was performed, continue anticonvulsants until local control is achieved and the patient remains seizure-free for an extended period. 1, 7
Reassess at each follow-up: The indication for anti-seizure therapy should be revisited at each follow-up visit, particularly in tumor patients where seizure control correlates with tumor control. 7
Critical Pitfalls to Avoid
Never assume medication failure without imaging: Breakthrough seizures in postoperative patients, especially those with brain tumors, often herald tumor progression or other structural complications requiring immediate neuroimaging. 1, 7
Do not use prophylaxis in seizure-naive patients: Primary anticonvulsant prophylaxis is not indicated in brain tumor or craniotomy patients who have never seized, as perioperative AEDs have no impact on seizure outcomes within 14 days of surgery. 2, 1
Avoid abrupt discontinuation: Do not abruptly stop anticonvulsants in patients with established postoperative seizure disorder, even when considering medication changes. 7
Monitor for complications: Patients with convulsive seizures have 2.5 times higher in-hospital mortality rates and twice the length of hospital stay compared to those without seizures. 5