What is the initial workup and management for an 11-year-old presenting with seizure activity?

Initial Workup and Management for an 11-Year-Old Presenting with Seizure Activity

For an 11-year-old presenting with seizure activity, MRI is the preferred neuroimaging modality over CT due to its significantly higher sensitivity (55% vs 18%) for detecting clinically relevant abnormalities, and should be performed with a dedicated epilepsy protocol. 1, 2

Initial Assessment and Diagnostic Workup

History and Examination

• Determine seizure characteristics:
  • Focal vs. generalized onset
  • Duration of seizure
  • Associated symptoms (aura, automatisms, postictal state)
  • Precipitating factors (fever, sleep deprivation, stress)
• Assess for:
  • Developmental history
  • Prior seizures or family history of epilepsy
  • Recent head trauma
  • Medications or toxin exposure
  • Focal neurological deficits

Laboratory Studies

• Laboratory tests should be ordered based on clinical circumstances 1:
  • Complete blood count
  • Electrolytes, glucose, calcium, magnesium
  • Toxicology screening if drug exposure is suspected
  • Consider metabolic screening in appropriate cases

Neuroimaging

• MRI is the preferred imaging modality 1, 2:

  • Demonstrates focal brain abnormalities in 55% of children with seizures (compared to only 18% with CT)
  • Should include specific epilepsy protocol sequences:
    • T1-weighted volumetric acquisition (3D) with isotropic voxel size of 1 mm
    • High-resolution thin coronal slices for hippocampal evaluation
    • FLAIR sequences (both coronal and axial)

• CT has limited utility but may be appropriate in acute settings 1:

  • When MRI is not immediately available
  • If there are concerns about acute hemorrhage or mass effect requiring urgent intervention
  • Note that 78.8% of CT scans show no imaging findings in children with new-onset seizures
  • Nearly 30% of abnormalities are missed on CT that are later found on MRI

Electroencephalography (EEG)

• EEG is recommended as part of the standard neurodiagnostic evaluation 1
• Should be performed within 24-48 hours of the seizure when possible
• If routine EEG is not diagnostic but seizures are suspected, consider:
  • Video-EEG monitoring
  • Sleep-deprived EEG
  • Home video recording of events

Lumbar Puncture

• Limited value in first non-febrile seizure 1
• Should be performed when there is concern for:
  • Meningitis
  • Encephalitis
  • Subarachnoid hemorrhage (if suspected and not visible on imaging)

Management Approach

Acute Management

• Ensure airway, breathing, and circulation
• If actively seizing (status epilepticus):
  • Administer benzodiazepines (first-line)
  • Progress to second-line agents if seizures continue

Long-term Management Decisions

• Antiepileptic drug (AED) therapy is not routinely indicated after a single unprovoked seizure 3
• Consider AED therapy if:
  • Patient has had two or more unprovoked seizures
  • EEG shows epileptiform abnormalities
  • MRI demonstrates a structural lesion
  • There is a high risk for recurrence

AED Selection (if indicated)

• For focal seizures:

  • Levetiracetam is effective with strong evidence 4, 5
  • Starting dose: 10-20 mg/kg/day in two divided doses
  • Target dose: up to 60 mg/kg/day 4

• For generalized seizures:

  • Valproate, levetiracetam, lamotrigine, or topiramate may be considered 6, 5
  • Valproate starting dose: 10-15 mg/kg/day
  • Increase by 5-10 mg/kg/week to achieve optimal response
  • Target therapeutic range: 50-100 μg/mL 6

Special Considerations

Referral Guidelines

• Refer to tertiary care after failure of one antiepileptic drug (standard care) 5
• Optimal care involves referral of all infants after presentation with a seizure 5
• Consider expedited referral for:
  • Focal seizures with abnormal neurological exam
  • Abnormal MRI findings
  • Epileptiform abnormalities on EEG

Common Pitfalls to Avoid

1. Overreliance on CT imaging: CT misses approximately 30% of abnormalities detected by MRI 1, 2
2. Failure to consider non-epileptic events: Conditions such as syncope, migraine, and psychogenic events can mimic seizures 3
3. Delayed EEG: EEG should be performed as soon as possible after the seizure event
4. Unnecessary AED initiation: Not all first-time seizures require long-term AED therapy
5. Missing treatable causes: Always evaluate for potentially reversible causes of seizures (metabolic abnormalities, toxins, infections) 7

MRI has revolutionized the detection of structural abnormalities in children with seizures, with studies showing abnormalities in 31% of children with first recognized seizures 8. This higher detection rate supports the wider use of MRI in children with newly diagnosed seizures.