Which investigations are recommended for a child presenting with their first seizure to confirm a diagnosis of epilepsy?

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

Posted: 22 August 2025Updated: 22 August 2025 Guideline-Aligned (High Confidence) Clinically Reviewed
Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX

For a child presenting with their first seizure, the recommended investigations to support a diagnosis of epilepsy include:

  • Detailed clinical assessment: Take a detailed history from the child and their family, including eyewitness accounts or video footage of the seizure, and perform a physical examination to inform diagnosis .
  • Electrocardiogram (ECG): Perform a 12-lead ECG to identify any cardiac conditions that could mimic epileptic seizures .
  • Electroencephalogram (EEG): Consider a routine EEG while the child is awake to support diagnosis and provide information about seizure type or epilepsy syndrome. If EEG is requested, it should ideally be performed within 72 hours of the seizure. Provoking maneuvers such as hyperventilation and photic stimulation may be included after discussing benefits and risks with the family .
  • Sleep-deprived EEG: If the routine EEG is normal and agreed with the family, consider a sleep-deprived EEG to increase diagnostic yield .
  • Ambulatory EEG: If diagnostic uncertainty persists after routine and sleep-deprived EEGs, consider ambulatory EEG monitoring for up to 48 hours .
  • Neuroimaging: Offer an MRI scan unless the child has idiopathic generalized epilepsy or self-limited epilepsy with centrotemporal spikes. The MRI should be done within 6 weeks of referral using regionally agreed epilepsy protocols. If MRI is contraindicated, consider a CT scan .

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