A child who has had a single non-febrile seizure with a normal neurologic exam. Which diagnostic test is indicated?

A child who has had a single non-febrile seizure with a normal neurologic exam. Which diagnostic test is indicated?

• A. Computerized tomography (CT).
• B. Electroencephalogram (EEG).
• C. Magnetic resonance imaging (MRI).
• D. Polysomnography.

Answer: (B)

The key idea is that after a single unprovoked seizure in a child with a normal neurologic exam, the best next test is an electroencephalogram. EEG directly measures brain electrical activity and can reveal epileptiform discharges that indicate a likelihood of future seizures, helping to classify the event and guide prognosis and management. A normal EEG does not completely rule out epilepsy, but its findings shape how aggressively to pursue treatment and follow-up. Imaging isn’t routinely needed after one unprovoked seizure if the neurologic exam is normal. A CT scan is mainly for acute head injury or emergencies and exposes radiation without high yield here. MRI provides detailed structural information and is more sensitive for identifying lesions, but is typically reserved for cases with focal neurologic signs, persistent symptoms, or when EEG or history suggests a possible underlying brain abnormality. Polysomnography is a sleep study used for sleep-related disorders, not the initial test for a first unprovoked seizure.

The key idea is that after a single unprovoked seizure in a child with a normal neurologic exam, the best next test is an electroencephalogram. EEG directly measures brain electrical activity and can reveal epileptiform discharges that indicate a likelihood of future seizures, helping to classify the event and guide prognosis and management. A normal EEG does not completely rule out epilepsy, but its findings shape how aggressively to pursue treatment and follow-up.

Imaging isn’t routinely needed after one unprovoked seizure if the neurologic exam is normal. A CT scan is mainly for acute head injury or emergencies and exposes radiation without high yield here. MRI provides detailed structural information and is more sensitive for identifying lesions, but is typically reserved for cases with focal neurologic signs, persistent symptoms, or when EEG or history suggests a possible underlying brain abnormality. Polysomnography is a sleep study used for sleep-related disorders, not the initial test for a first unprovoked seizure.