What is the initial management approach for a patient presenting with focal seizures?

Initial Management of Focal Seizures

For adults presenting with focal seizures, obtain serum glucose and sodium levels immediately, perform neuroimaging (preferably MRI) in the emergency department when feasible, and initiate anti-seizure medication (ASM) with carbamazepine, levetiracetam, lamotrigine, or phenytoin based on patient-specific factors, recognizing that ~30% will develop drug resistance requiring surgical evaluation. 1, 2, 3

Immediate Emergency Department Evaluation

Essential Laboratory Studies

• Serum glucose and sodium are the only universally recommended laboratory tests for first-time seizure patients who have returned to baseline neurologic status 1
• Obtain pregnancy test in all women of childbearing age 1
• Additional laboratory studies (CBC, calcium, comprehensive metabolic panel) should be ordered only when clinical circumstances suggest specific abnormalities such as vomiting, diarrhea, dehydration, or failure to return to baseline alertness 4

Neuroimaging Requirements

Perform neuroimaging of the brain in the ED when feasible for all patients with first-time focal seizures 1. The evidence strongly supports this approach:

• MRI is superior to CT and should be the primary imaging modality for newly diagnosed seizures, detecting abnormalities in 55% of focal seizure patients versus only 18% with CT 1
• In focal seizures specifically, approximately 50% of CT examinations show positive findings, and 28.2% of patients have abnormal MRI findings not visible on initial CT 1, 2
• MRI with dedicated epilepsy protocols (3T scanners, 1mm isotropic voxels, high-resolution coronal hippocampal sequences) is essential to identify structural lesions including hippocampal sclerosis, tumors, focal cortical dysplasia, and vascular malformations 2

Emergent neuroimaging is indicated when:

• New focal neurologic deficits present 1
• Persistent altered mental status 1
• Fever, recent head trauma, or persistent headache 1
• History of malignancy, anticoagulation, or known HIV 1
• Age >40 years 1
• Focal onset before generalization 1

Deferred outpatient neuroimaging may be considered only when reliable follow-up is available and none of the above high-risk features are present 1

Electroencephalography (EEG)

• EEG is recommended as part of the neurodiagnostic evaluation for apparent first unprovoked seizures (high strength of evidence) 4
• Standard EEG helps differentiate focal from generalized seizures and guides treatment decisions 5, 6
• Video EEG monitoring may be necessary to establish correct diagnosis when the clinical picture is unclear 5

Lumbar Puncture Considerations

• Perform lumbar puncture (after head CT) on immunocompromised patients presenting with seizures, either in the ED or after admission 1

Pharmacological Treatment Initiation

First-Line Monotherapy Options

Seven drugs have Level A evidence for initial monotherapy in focal seizures, with no robust data supporting superiority of one over another 3. Treatment decisions should be driven by:

• Adverse effect profiles
• Patient age
• Pregnancy potential
• Concomitant diseases and medications
• Cost considerations 5, 3

Commonly used first-line agents include:

• Carbamazepine 5, 3
• Levetiracetam 7, 3
• Lamotrigine 5, 3
• Phenytoin 5
• Valproic acid (sodium valproate) 5
• Oxcarbazepine 5

Levetiracetam-Specific Considerations (FDA-Approved)

Levetiracetam is rapidly and almost completely absorbed after oral administration with linear, time-invariant pharmacokinetics 7. Key safety considerations:

• Behavioral abnormalities are associated with levetiracetam treatment: non-psychotic behavioral disorders (aggression, irritability) occurred in 5-11.4% versus 0-3.6% in placebo 7
• Non-psychotic mood disorders (depression, mood swings) occurred in 6.7-12.7% versus 3.3-8.3% in placebo 7
• Somnolence may require dose reduction 7
• Withdraw gradually to minimize potential of increased seizure frequency 7

Decision Not to Treat

Patients with normal neurologic examination, normal test results, and no structural brain disease do not require hospitalization or immediate antiepileptic medications 6. However, consider:

• Focal seizures have recurrence rates up to 94%, considerably higher than generalized seizures at 72% 2
• Treatment with ASMs reduces 1-2 year risk of recurrent seizures but does not reduce long-term recurrence risk or affect remission rates 6
• The presence of any focal feature is independently associated with clinically relevant abnormalities on neuroimaging 2

Drug-Resistant Focal Epilepsy Recognition

Critical Threshold for Surgical Evaluation

Approximately 30% of focal epilepsy patients do not respond to two ASMs and are considered drug resistant 1, 2. This is a critical inflection point:

• Focal epilepsies demonstrate significantly higher drug resistance rates compared to generalized epilepsies 2
• In children, approximately 20% develop drug resistance with associated poor long-term cognitive and psychosocial outcomes 1, 2
• Epilepsy surgery achieves seizure freedom in approximately 65% of appropriately selected drug-resistant cases 1, 2

Advanced Imaging for Surgical Candidates

When drug resistance develops:

• FDG-PET and ictal/interictal SPECT become valuable adjuncts, particularly for non-lesional cases or multifocal abnormalities, to localize seizure onset for surgical planning 1, 2
• These functional imaging tools are especially useful in patients without visible brain lesions on MRI or with multifocal structural cerebral abnormalities 1

Disposition Decisions

Admission Criteria

The literature provides limited guidance on admission decisions 1. Consider admission for:

• Patients with acute intracranial pathology identified on imaging
• Immunocompromised patients requiring lumbar puncture
• Patients with persistent altered mental status
• Those requiring intravenous ASM initiation
• Unreliable follow-up or social concerns 1

Discharge Considerations

Patients may be discharged when:

• Returned to baseline neurologic status
• No acute intracranial pathology identified
• Reliable outpatient follow-up arranged
• Social situation supports safe discharge 1

Critical caveat: A seizure diagnosis severely limits driving privileges, although laws vary by state 6

Common Pitfalls to Avoid

• Do not rely solely on CT imaging: MRI detects 28.2% more abnormalities in focal seizures 1
• Do not order extensive laboratory panels routinely: Only glucose and sodium have evidence-based support for all patients 1
• Do not delay surgical evaluation in drug-resistant cases: Early referral to epilepsy centers improves outcomes 1, 2
• Do not assume normal neurologic examination excludes significant pathology: 22% of patients with normal exams had abnormal CT findings 1
• Do not confuse focal seizures with generalized seizures: The presence of any focal feature dramatically changes imaging yield and treatment approach 2