Presented by Megan Fellows, MD, MPH (PGY-3)
Clinical Question:
Long-term consequences of febrile status epilepticus
Review of Febrile Seizure:
- Simple
- Generalized, < 15 minutes, do not recur in 24-hour period
- MC generalized TC
- Complex
- Focal, prolonged, often recur within 24-hour period
- Often younger
- Status Epilepticus
- Continuous seizures or intermittent without neurologic recovery
Article #1 Reviewed:
Shinnar, S., Hesdorffer, D. C., Nordli, D. R., Jr, Pellock, J. M., O’Dell, C., Lewis, D. V., Frank, L. M., Moshé, S. L., Epstein, L. G., Marmarou, A., Bagiella, E., & FEBSTAT Study Team (2008). Phenomenology of prolonged febrile seizures: results of the FEBSTAT study. Neurology, 71(3), 170–176. https://doi.org/10.1212/01.wnl.0000310774.01185.97
FEBSTAT Study
Article #2 Reviewed:
Lewis, D. V., Shinnar, S., Hesdorffer, D. C., Bagiella, E., Bello, J. A., Chan, S., Xu, Y., MacFall, J., Gomes, W. A., Moshé, S. L., Mathern, G. W., Pellock, J. M., Nordli, D. R., Jr, Frank, L. M., Provenzale, J., Shinnar, R. C., Epstein, L. G., Masur, D., Litherland, C., Sun, S., … FEBSTAT Study Team (2014). Hippocampal sclerosis after febrile status epilepticus: the FEBSTAT study. Annals of neurology, 75(2), 178–185. https://doi.org/10.1002/ana.24081
Free full-text access.
Study Design:
- What type of study – Prospective cohort
- Population
- 226 children 1 month to 6 years
- Inclusion Criteria
- FSE > 30 minutes or repetitive FS lasting at least 30 min
- Relevant inclusion and exclusion criteria
- Included children with pre-existing MRI abnormalities
- Controls: Children with simple febrile seizures
- Methods
- MRI obtained following acute episode of FSE and follow up MRI obtained ~1 year later
- MRIs read by two different neuroradiologists
- Assessed for Hippocampal hyperintensity in T2, hippocampal volumes, apparent diffusion coefficient
- Outcomes
- Hippocampal T2 intensity occurred after FSE in 22 of 226 children
- f/u MRI on 14 of 22 showed hippocampal sclerosis in 10 and reduced hippocampal volume in 12.
- Compared to controls with SF, FSE subjects with normal acute MRI had low right too left hippocampal volume rations, smaller hippocampi initially and reduced hippocampal growth.
Relevant Data:
Hippocampal T2 Signal following FSE:
(A) Sommer’s region
(B) MRI 72 hrs after FSE
(C) MRI 6 months later in same child
Discussion / Summary of Study:
- FEBSTAT and other studies have established that acute hippocampal injury is visible on MRI following FSE
- Hippocampal injury max in Sommer’s region acutely and that many hippocampi lose volume meeting radiologic criteria for HS
- Abnormal hippocampal growth reported after FSE even if normal appearing MRI following acute episode.
- Still can’t say for certain if FSE can lead to development o temporal lobe epilepsy as longer term follow up is needed and studies are underway.
Limitations and Challenges:
- No baseline MRI prior to FSE thus unable to know if ADCs and volumetric measurements visualized on MRI were acute and secondary to FSE alone
- Abnormal hippocampal signal following FSE showing radiological HS after a year but no pathological confirmation.
- Loss to follow up at 1 year often due to parental concerns about sedated MRI
Learning Points:
- Always ensure that we have a comprehensive seizure action plan esp. in patients with known seizure disorders
- Don’t be afraid to call neurology
- “Time is brain” in febrile status epilepticus
References:
- Hesdorffer, D. C., Shinnar, S., Lewis, D. V., Moshé, S. L., Nordli Jr, D. R., Pellock, J. M., … & FEBSTAT Study Team. (2012). Design and phenomenology of the FEBSTAT study. Epilepsia, 53(9), 1471-1480.
- Lewis, D. V., Shinnar, S., Hesdorffer, D. C., Bagiella, E., Bello, J. A., Chan, S., … & FEBSTAT Study Team. (2014). Hippocampal sclerosis after febrile status epilepticus: the FEBSTAT study. Annals of neurology, 75(2), 178-185.
Presented by Zachary West, MD (PGY-2)
Presented by Kaamilah Wilson, MD (PGY-1)
Presented by Vanessa Nguyen, DO (PGY-2)
Pediatric Focus 