What is the initial workup and treatment for a patient with a seizure disorder?

Initial Workup for Seizure Disorder

For a patient presenting with new-onset seizure, immediately obtain serum glucose and sodium levels, perform neuroimaging based on risk stratification, and obtain EEG to assess recurrence risk and guide treatment decisions. 1

Immediate Laboratory Assessment

The initial laboratory workup should be targeted rather than comprehensive:

• Obtain serum glucose and sodium levels in all patients, as these are the only laboratory abnormalities that consistently alter acute management 1
• Perform pregnancy test in all patients of childbearing age to identify pregnancy-related seizures and guide medication selection 1
• Consider toxicology screening if there is any suspicion of drug exposure or substance abuse 1
• Additional labs (CBC, comprehensive metabolic panel, calcium, magnesium) should only be obtained when specific clinical findings suggest them, such as in patients with known cancer or renal failure 1

A critical pitfall: approximately 23% of first-time seizure patients have abnormal physical examinations and various laboratory abnormalities, but only glucose and sodium abnormalities consistently require immediate intervention 1

Neuroimaging Strategy

Use a risk-stratified approach to determine timing and modality of neuroimaging:

High-Risk Features Requiring Emergent CT Head Without Contrast 1:

• Age >40 years
• History of malignancy or immunocompromised state
• Recent head trauma
• Fever or persistent headache
• Focal seizure onset before generalization
• New focal neurological deficits
• Persistent altered mental status
• Patients on anticoagulation

Approximately 41% of first-time seizure patients have abnormal CT findings, and 22% of patients with normal neurologic examinations still have abnormal imaging 1

Low-Risk Patients:

• Deferred outpatient MRI is acceptable for young patients who have returned to baseline, have normal neurologic examination, and have reliable follow-up arrangements 1
• MRI is the preferred imaging modality for non-emergent evaluation as it is more sensitive than CT for detecting epileptogenic lesions 1

Electroencephalography (EEG)

EEG should be obtained as part of the neurodiagnostic evaluation in all patients with apparent first unprovoked seizure 1

• Abnormal EEG findings predict increased risk of seizure recurrence and help guide treatment decisions 1
• EEG helps differentiate epileptic events from nonepileptic events, as approximately 28-48% of suspected first seizures have alternative diagnoses (syncope, nonepileptic seizures, panic attacks) 1

Lumbar Puncture Indications

Lumbar puncture should be performed primarily when there is concern for meningitis or encephalitis 1

Specific indications include:

• Fever with meningeal signs
• Immunocompromised patients (after head CT) 1
• Persistent altered mental status without clear etiology

Routine lumbar puncture is not indicated for uncomplicated first-time seizures 1

Risk Stratification for Seizure Recurrence

Understanding recurrence risk is essential for treatment decisions:

• The mean time to first seizure recurrence is 121 minutes (median 90 minutes), with >85% of early recurrences occurring within 6 hours of ED presentation 1
• Overall 24-hour recurrence rate is 19%, decreasing to 9% when alcohol-related events and focal CT lesions are excluded 1
• Nonalcoholic patients with new-onset seizures have the lowest recurrence rate (9.4%), while alcoholic patients with seizure history have the highest (25.2%) 1
• Risk of recurrence at 1 year ranges from 14-36%, with higher risk in those with abnormal neurological examination, abnormal EEG, remote symptomatic seizures, or Todd's paralysis 1

Initial Treatment Decisions

When to Initiate Antiepileptic Drugs:

Antiepileptic drug treatment reduces 1-2 year recurrence risk but does not affect long-term recurrence rates or remission rates 1

• Start treatment for patients with newly diagnosed epilepsy (two or more unprovoked seizures) 2
• For single unprovoked seizures, treatment decision depends on individual risk factors including abnormal EEG, structural brain lesion on imaging, and history of brain insult 2
• Do not treat provoked seizures with AEDs; instead, address the underlying provoking factor 3, 4

First-Line Medication Selection:

Levetiracetam is the preferred first-line agent for most patients due to its efficacy and overall good tolerability 5

• Initiate levetiracetam at 1000 mg/day (500 mg BID), with potential titration by 1000 mg/day every 2 weeks to a maximum of 3000 mg/day 6
• Lamotrigine is an alternative first-line option, though it requires several weeks to reach therapeutic levels 5
• Valproic acid remains effective but must not be used in females who may become pregnant and requires monitoring for drug interactions 5

Medications to Avoid:

Phenytoin, phenobarbital, and carbamazepine are no longer recommended as first-choice agents due to their side-effect profile and significant drug interactions, especially with steroids and various cytotoxic agents 5, 7

Disposition Decisions

Emergency physicians need not admit patients with a first unprovoked seizure who have returned to their clinical baseline in the ED 1

Consider admission if any of the following are present:

• Persistent abnormal neurologic examination results
• Abnormal investigation results requiring inpatient management
• Patient has not returned to baseline 1

Special Considerations

Alcohol-Related Seizures:

Alcohol withdrawal seizures should be a diagnosis of exclusion, especially in first-time seizures, and symptomatic causes should always be searched for before labeling as withdrawal seizures 1

Status Epilepticus:

Benzodiazepines are first-line therapy for status epilepticus, followed by either phenytoin/fosphenytoin, valproate, or levetiracetam 1

Driving Restrictions:

Judgements on competency to drive need to adhere to national guidelines and law and should consider not only epilepsy but also other aspects of neurological and neurocognitive function 5