Utility of initial EEG in first complex febrile seizure

Chellamani Harini; Elanagan Nagarajan; Amir A Kimia; Rachel Marin de Carvalho; Sookee An; Ann M Bergin; Masanori Takeoka; Phillip L Pearl; Tobias Loddenkemper

doi:10.1016/j.yebeh.2015.09.003

Utility of initial EEG in first complex febrile seizure

Epilepsy Behav. 2015 Nov;52(Pt A):200-4. doi: 10.1016/j.yebeh.2015.09.003. Epub 2015 Oct 6.

Authors

Chellamani Harini¹, Elanagan Nagarajan², Amir A Kimia³, Rachel Marin de Carvalho², Sookee An², Ann M Bergin², Masanori Takeoka², Phillip L Pearl², Tobias Loddenkemper²

Affiliations

¹ Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Boston, MA, USA. Electronic address: Chellamani.harini@childrens.harvard.edu.
² Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Boston, MA, USA.
³ Division of Emergency Medicine, Boston Children's Hospital, Boston, MA, USA.

PMID: 26448592
DOI: 10.1016/j.yebeh.2015.09.003

Abstract

Objective: The risk of developing epilepsy following febrile seizures (FS) varies between 2% and 10%, with complex febrile seizures (CFS) having a higher risk. We examined the utility of detected epileptiform abnormalities on the initial EEG following a first CFS in predicting subsequent epilepsy.

Methods: This was a retrospective study of consecutive patients (ages 6-60 months) who were neurologically healthy or mildly delayed, seen in the ED following a first CFS and had both an EEG and minimum of 2-year follow-up. Data regarding clinical characteristics, EEG report, development of subsequent epilepsy, and type of epilepsy were collected. Established clinical predictors for subsequent epilepsy in children with FS and EEG status were evaluated for potential correlation with the development of subsequent epilepsy. Sensitivity, specificity, and positive and negative predictive values of an abnormal EEG (epileptiform EEG) were calculated.

Results: A group of 154 children met our inclusion criteria. Overall, 20 (13%) children developed epilepsy. The prevalence of epilepsy was 13% (CI 8.3-19.6%). Epileptiform abnormalities were noted in 21 patients (13.6%), EEG slowing in 23 patients (14.9%), and focal asymmetry in six (3.8%). Epileptiform EEGs were noted in 20% (4/20) of patients with epilepsy and 13% (17/134) of patients without epilepsy (p=0.48). At an estimated risk of subsequent epilepsy of 10% (from population-based studies of children with FS), we determined that the PPV of an epileptiform EEG for subsequent epilepsy was 15%. None of the clinical variables (presence of more than 1 complex feature, family history of epilepsy, or status epilepticus) predicted epilepsy.

Conclusions: An epileptiform EEG was not a sensitive measure and had a poor positive predictive value for the development of epilepsy among neurologically healthy or mildly delayed children with a first complex febrile seizure. The practice of obtaining routine EEG for predicting epilepsy after the first CFS needs clarification by well-defined prospective studies.

Keywords: Complex febrile seizures; Diagnosis; EEG; Epilepsy.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Anticonvulsants / therapeutic use
Child
Child, Preschool
Electroencephalography*
Female
Follow-Up Studies
Humans
Infant
Male
Predictive Value of Tests
Prevalence
Prognosis
Prospective Studies
Retrospective Studies
Risk Assessment
Seizures / diagnosis
Seizures / physiopathology
Seizures, Febrile / diagnosis*
Seizures, Febrile / physiopathology

Substances

Anticonvulsants