Workup for New Onset Seizures in a 12-Year-Old Female
The initial workup for new onset seizures in a 12-year-old female should include serum glucose and sodium testing, neuroimaging with MRI (or CT if emergent), and EEG, with admission considered for patients who have not returned to baseline or have concerning findings on initial evaluation. 1
Initial Assessment and Laboratory Testing
- Determine serum glucose and sodium levels, as these are the most frequent abnormalities identified in patients with new-onset seizures 1
- Obtain a pregnancy test if the patient has reached menarche 1
- Consider toxicology screening if there is any question of drug exposure or substance abuse across the entire pediatric age range 1
- Basic laboratory tests should be guided by clinical circumstances including suggestive historic or clinical findings such as vomiting, diarrhea, or dehydration 1
Neuroimaging
- MRI is the preferred imaging modality for new-onset seizures when not in an emergent situation 1
- CT head without contrast can be performed in emergent situations as it can rapidly identify structural pathology such as intracranial hemorrhage, stroke, vascular malformation, hydrocephalus, and tumors 1
- Emergent neuroimaging should be performed if the patient exhibits a postictal focal deficit that does not quickly resolve or has not returned to baseline within several hours after the seizure 1
- Non-urgent MRI should be considered in any child with:
- Significant cognitive or motor impairment of unknown etiology
- Unexplained abnormalities on neurologic examination
- Seizure of partial onset with or without secondary generalization
- EEG that does not represent a benign partial epilepsy of childhood or primary generalized epilepsy 1
Electroencephalography (EEG)
- EEG is recommended as part of the neurodiagnostic evaluation of a child with an apparent first unprovoked seizure 1
- EEG helps determine risk of recurrence and the need for long-term treatment 2
Lumbar Puncture
- Lumbar puncture is of limited value in a child with a first non-febrile seizure and should be used primarily when there is concern about possible meningitis or encephalitis 1
- Consider lumbar puncture in patients who are immunocompromised 1
- Lumbar puncture should be performed after a head CT scan if indicated 1
NPO Status Management
- Keep the patient NPO immediately after seizures until swallowing screening is completed to prevent aspiration 3
- Assess for return to clinical baseline before allowing oral intake 3
- Monitor for changes in neurological status 3
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:
Risk of Recurrence
- The mean time to first seizure recurrence is 121 minutes (median 90 minutes) with more than 85% of early seizures recurring within 360 minutes (6 hours) 1
- Nonalcoholic patients with new-onset seizures have the lowest early seizure recurrence rate (9.4%) 1
- The risk of seizure recurrence increases substantially after 2 or 3 unprovoked seizures 3
Common Pitfalls to Avoid
- Failing to identify metabolic abnormalities such as hypoglycemia or hyponatremia that may be causing the seizure 1
- Allowing oral intake too early before proper swallowing assessment, which can lead to aspiration pneumonia 3
- Not recognizing that a patient's swallowing ability can change in the hours following seizures, requiring ongoing monitoring 3
- Missing structural lesions by not performing appropriate neuroimaging 1
- Failing to distinguish between provoked seizures (which may not require long-term treatment) and unprovoked seizures (which may indicate epilepsy) 5, 2
By following this structured approach to the evaluation of new-onset seizures in a 12-year-old female, clinicians can ensure appropriate diagnosis and management while avoiding unnecessary testing or treatment.