Imaging After Second Febrile Seizure in a 2-Year-Old
Routine neuroimaging is NOT indicated for this 2-year-old with a second febrile seizure within 24 hours, as this meets criteria for a complex febrile seizure, and imaging recommendations remain the same as for simple febrile seizures unless specific red flags are present. 1, 2
Classification and Imaging Recommendations
This presentation represents a complex febrile seizure because the seizures recurred within 24 hours. 1, 3 However, the key clinical principle is that imaging recommendations do not change based on simple versus complex classification alone. 1, 2
Standard Imaging Approach
- Brain MRI or CT is not routinely indicated for complex febrile seizures, including recurrent seizures within 24 hours. 1, 2, 3
- In children with febrile seizures recurrent within 24 hours, neuroimaging revealed benign findings in only 7.4% of patients and did not add significant diagnostic or prognostic information. 1
- While imaging abnormalities occur in 14.8% of complex febrile seizures (compared to 11.4% in simple febrile seizures), these findings rarely alter clinical management. 1, 2
Red Flags That WOULD Warrant Imaging
Imaging should be obtained if any of the following are present:
- Post-ictal focal neurological deficits that persist beyond the typical post-ictal period 2, 4
- Failure to return to baseline mental status within several hours (not just 30 minutes of drowsiness) 4
- Clinical concern for meningitis, encephalitis, or intracranial infection 2, 5, 6
- History of significant head trauma 4
- Signs of increased intracranial pressure 4
- Febrile status epilepticus (seizure lasting >15 minutes) 2
Appropriate Diagnostic Workup Instead
Since imaging is not indicated, focus on:
Immediate Assessment
- Rule out CNS infection clinically - this is the primary diagnostic concern. 5, 6
- Lumbar puncture should be performed if there are any meningeal signs, septic appearance, or behavioral disturbance. 5
- For a well-appearing child with no meningeal signs, lumbar puncture is not necessary even with recurrent seizures within 24 hours. 5
Recommended Evaluations
- EEG and neurology consultation are recommended for complex febrile seizures due to small increased risk of developing epilepsy later. 2, 3, 7
- Identify and treat the source of fever - this is the primary diagnostic goal. 6, 8
- Blood glucose measurement if the child has prolonged altered mental status. 4
Common Pitfalls to Avoid
- Do not order routine neuroimaging without specific clinical indications, as it adds cost without changing management in most cases. 2
- Do not assume imaging is needed just because this is a "second" seizure - the recurrence within 24 hours defines it as complex, but imaging criteria remain unchanged. 1, 2
- Do not miss meningitis - this must be excluded clinically or by lumbar puncture if any doubt exists, as seizures are the presenting sign in one in six children with meningitis. 6
- Ensure early clinical re-evaluation (at least 4 hours after initial assessment) can be helpful, particularly in younger children. 5