What is the initial approach to a pediatric seizure workup?

Pediatric Seizure Workup

Initial Clinical Assessment

The workup of pediatric seizures must be stratified by age, presence of fever, and clinical context, with imaging and laboratory testing guided by specific clinical indicators rather than performed routinely. 1, 2

Age-Specific Approach

Neonates (0-29 days):

• Head ultrasound is the preferred initial imaging modality for unstable neonates or when MRI is unavailable, as it identifies intraventricular hemorrhage, hydrocephalus, and white matter changes at the bedside 1
• MRI head without contrast is the definitive imaging study when the infant is stable, as 95% of neonatal seizures have an identifiable cause (most commonly hypoxic-ischemic injury 46-65%, followed by intracranial hemorrhage and stroke 10-12%) 1
• CT head may identify structural anomalies but exposes the neonate to radiation 1

Infants and children (1 month-18 years):

• The approach depends critically on whether fever is present and seizure characteristics 1

Febrile Seizures

Simple febrile seizures (generalized, <15 minutes, single episode in 24 hours) require NO imaging or laboratory workup in the absence of other neurological signs 1

Complex febrile seizures (>15 minutes, >1 episode in 24 hours, or focal features):

• Neuroimaging is NOT routinely indicated unless specific concerns exist for meningitis, encephalitis, or trauma 1
• EEG and neurology evaluation are recommended 1, 3
• In febrile status epilepticus (>30 minutes), MRI may be indicated due to increased association with imaging findings 1
• CT head reveals no findings requiring intervention in complex febrile seizures (analysis of 161 children showed zero actionable findings) 1

Unprovoked/Afebrile Seizures

Laboratory Testing:

• Obtain serum glucose and sodium in ALL patients with new-onset seizures, as these are the only commonly treatable metabolic causes 2
• Pregnancy testing is mandatory for all females of childbearing age 2
• Routine comprehensive metabolic panels, calcium, magnesium, and toxicology screens are NOT indicated unless specific clinical suspicion exists, as they rarely identify seizure causes and do not alter management 4, 5
• In one study of 308 children, 40% had at least one test performed, but no abnormal result caused the seizure or changed treatment 4

Neuroimaging:

• MRI brain without contrast is the preferred imaging modality for first unprovoked seizures, particularly with focal features, abnormal neurological examination, or status epilepticus 2, 6
• MRI should be performed in children with focal seizures, developmental delay, or abnormal neurological findings 6, 5
• Brain imaging should NOT be routine but rather guided by detailed history and physical examination 5
• In 61 patients who underwent imaging, 26% had abnormalities, but 75% of these had abnormal histories or examinations suggesting the need for imaging 5

Electroencephalography:

• EEG during wakefulness and sleep is recommended for all children with first unprovoked seizures 6, 7

Post-Traumatic Seizures

CT head without contrast is the initial imaging of choice to identify acute hemorrhage or mass effect requiring urgent intervention 1, 8

• CT identifies 100% of acutely treatable lesions, with 7% requiring urgent surgical intervention 8
• MRI is more sensitive for microhemorrhages and diffuse axonal injury but is impractical in the acute setting 1, 8
• Short-term prophylactic antiepileptic drugs (≤7 days) may be considered in the immediate post-traumatic period, with levetiracetam preferred over phenytoin 8

Critical Decision Points

When to image:

• Neonatal seizures (always) 1
• First unprovoked seizure with focal features 6, 7
• Abnormal neurological examination 5
• Developmental delay 6
• Status epilepticus 6
• Post-traumatic presentation 1, 8
• Suspected meningitis, encephalitis, or structural lesion 1

When NOT to image:

• Simple febrile seizures 1
• Complex febrile seizures without other neurological indicators 1
• Generalized seizures with normal examination and no concerning history 5

Common Pitfalls

• Avoid routine laboratory panels in well-appearing children with febrile seizures, as electrolyte abnormalities causing seizures are exceedingly rare (3/319 patients in one series) 5
• Do not obtain CT for complex febrile seizures unless specific concerns for acute pathology exist, as it provides no actionable information and exposes children to radiation 1
• Recognize that most children (94%) presenting with first seizures are under 6 years of age, and febrile seizures account for 62% of first seizures in this population 5
• Risk factors for developing epilepsy include febrile seizures, status epilepticus, family history, developmental delay, and abnormal neurological examination 6