What is the appropriate evaluation and treatment plan for an adult or child who has experienced a first seizure?

Management of First Seizure in Adults and Children

For patients with a first unprovoked seizure who have returned to their clinical baseline, discharge from the emergency department without initiating antiepileptic medication is appropriate, as treatment does not improve long-term outcomes despite reducing short-term recurrence risk. 1

Initial Evaluation and Risk Stratification

Essential Laboratory Testing

• Obtain serum glucose and sodium levels immediately - these are the only laboratory abnormalities that consistently alter acute management 2, 3
• Perform pregnancy testing in all women of childbearing age, as this significantly impacts medication choices 2
• Additional laboratory tests (CBC, comprehensive metabolic panel) should be obtained only when suggested by specific clinical findings such as vomiting, diarrhea, dehydration, or known renal failure 1, 2
• Toxicology screening should be considered if there is any question of drug exposure or substance abuse 2

Neuroimaging Decision Algorithm

High-risk patients requiring emergent CT head without contrast in the ED: 2, 3

• Age >40 years
• Recent head trauma
• Persistent altered mental status or failure to return to baseline
• New focal neurological deficits
• Fever or persistent headache suggesting CNS infection
• History of malignancy or immunocompromised state
• Anticoagulation use
• Partial-onset seizure pattern

Low-risk patients (young, returned to baseline, normal neurologic exam, reliable follow-up) can have deferred outpatient MRI, which is the preferred imaging modality for non-emergent evaluation 2

Critical caveat: 22% of patients with normal neurologic examinations still have abnormal CT findings, and 23% of patients with new-onset seizures have acute stroke or tumor on CT 3. This is particularly important in elderly patients where deferring neuroimaging can be dangerous 3.

Lumbar Puncture Indications

• Concern for meningitis or encephalitis (fever with meningeal signs) 2
• Immunocompromised patients (after head CT) 1, 2
• Not indicated for uncomplicated first-time seizures 2

Electroencephalography (EEG)

• Recommended as part of the neurodiagnostic evaluation in children with an apparent first unprovoked seizure 2
• Abnormal EEG findings predict increased risk of seizure recurrence 2

Disposition and Admission Decisions

Discharge Criteria (All Must Be Present)

• Patient has returned to clinical baseline 1, 2
• Normal neurological examination 2
• No persistent altered mental status 2
• No abnormal investigation results requiring inpatient management 2
• Reliable follow-up arrangements established 2

Admission Indications (Any One Present)

• Persistent abnormal neurological examination results 1, 2
• Failure to return to baseline within several hours 2
• Abnormal investigation results requiring inpatient management 1, 2
• Postictal focal deficit that does not quickly resolve 2

Seizure Recurrence Risk

Early recurrence timeline: 1, 2

• Mean time to first recurrence: 121 minutes (median 90 minutes)
• 85% of early recurrences occur within 6 hours (360 minutes)
• Overall 24-hour recurrence rate: 19%
• When excluding alcohol-related events and focal CT lesions: 9%

Risk stratification by patient type: 1

• Nonalcoholic patients with new-onset seizures: 9.4% early recurrence (lowest risk)
• Alcoholic patients with seizure history: 25.2% early recurrence (highest risk)

Long-term recurrence: 1

• Approximately one-third of patients with a first unprovoked seizure will have recurrent seizure within 5 years
• Risk increases substantially to three-quarters after 2-3 recurrent unprovoked seizures

Antiepileptic Drug Treatment Decision

First Unprovoked Seizure - Generally DO NOT Treat

The strategy of waiting until a second seizure before initiating antiepileptic medication is considered appropriate for patients with a first unprovoked seizure 1. The rationale:

• Treatment prolongs time to subsequent event but outcomes at 5 years are no different 1
• Number needed to treat (NNT) to prevent a single seizure recurrence within first 2 years: 14 patients 1
• Treatment exposes patients to medication adverse effects without proven mortality or morbidity benefit 2

Exceptions - Consider Treatment After First Seizure

Provoked/symptomatic seizures: 1

• NNT to prevent single additional seizure in following year: approximately 5
• Treatment is considered appropriate after 1 seizure

Remote symptomatic seizures (history of CNS injury): 1

• History of stroke, traumatic brain injury, tumor, or other CNS disease/injury
• These conditions provide anatomic/physiologic substrate for recurrent seizures
• Treatment is considered appropriate after 1 seizure due to higher recurrence rate

Special Populations

Pediatric Considerations

• For simple febrile seizures (ages 6 months-5 years): neuroimaging is not indicated 2
• For complex febrile seizures: neuroimaging generally unnecessary unless other neurological indications present 2
• Treatment should be initiated at 20 mg/kg/day in 2 divided doses, increased every 2 weeks by 20 mg/kg increments to recommended 60 mg/kg/day if levetiracetam is chosen 4

Elderly Patients (>40 years)

• Emergent head CT is mandatory - 23% have acute stroke or tumor 3
• Do not defer neuroimaging in this population due to high rate of serious structural lesions 3
• Age >40 years alone is an indication for emergent ED neuroimaging 2, 3

Common Pitfalls to Avoid

• Misdiagnosis: 28-48% of suspected first seizures have alternative diagnoses (syncope, nonepileptic seizures, panic attacks) - careful history is essential 2
• Missing metabolic causes: Failing to identify hypoglycemia or hyponatremia that require immediate intervention 2
• Alcohol withdrawal assumption: Alcohol withdrawal seizures should be a diagnosis of exclusion, especially in first-time seizures - always search for symptomatic causes 2
• Deferring imaging in high-risk patients: Missing structural lesions by not performing appropriate neuroimaging, particularly in elderly patients 2, 3
• Routine extensive testing: Obtaining unnecessary laboratory panels when only glucose and sodium have sufficient evidence for routine testing 2, 3