Could MRI and EEG predict risk of epilepsy following febrile seizures- FEBSTAT study suggests

Preliminary results from the FEBSTAT study has revealed that within days of a prolonged fever-related seizure, some children have signs of acute brain injury, abnormal brain anatomy, altered brain activity, or a combination.Febrile Seizures affect 3 to 4 percent of all children. Most such children recover rapidly and do not suffer long-term health consequences. However, having one or more prolonged febrile seizures in childhood is known to increase the risk of subsequent epilepsy which is estimated to be about 30-40 percent following febrile status epilepticus (FSE).

The Consequences of Prolonged Febrile Seizures in Childhood (FEBSTAT) study is focused specifically on FSE and the risk of temporal lobe epilepsy.Within days of FSE, the children in the study underwent magnetic resonance imaging (MRI) and electroencephalography (EEG). The MRI findings were reported in July 2012, and the EEG findings were reported in November 2012. Both papers were published in Neurology.

FEBSTAT began almost 10 years ago. 199 Children, aged between one month and six years with FSE were enrolled from 2003-2010 at five sites: Montefiore Medical Center and Jacobi Hospital in the New York City; Lurie Children's Hospital in Chicago; Duke University Medical Center in Durham, N.C.; Virginia Commonwealth University Hospital in Richmond; and Eastern Virginia Medical School in Norfolk.A further 96 children who had experienced a single, simple febrile seizure (lasting 10 minutes or less) were also recruited and served as the comparison (control) group.

The children underwent blood tests, a neurological exam, MRI, and EEG within 72 hours of being seen in the emergency room for FSE. The blood samples are being analyzed for viral infections linked to febrile seizures and for the presence of gene mutations that could contribute to epilepsy. The children continue to receive neurological exams, MRI and EEG at regular intervals.

The MRI scans revealed that FSE is sometimes associated with abnormalities in the hippocampus. Of 191 children with FSE, 22 (11.5 percent) had signs of hippocampal injury on MRI, and 20 (10.5 percent) had developmental abnormalities of the hippocampus. Abnormal MRI results were rare among children with simple febrile seizures, defined as lasting 10 minutes or less. Out of 96 children with such seizures, only two (2.1 percent) had developmental abnormalities of the hippocampus and none had signs of brain injury.

Nearly half (45.2 percent) of the children with FSE had abnormal EEG findings. There was also a correlation between the MRI and EEG findings. Children with evidence of acute brain injury after FSE were more than twice as likely to have abnormal EEG findings. The results suggested that in some children prolonged febrile seizures do result in brain injury. In some others pre-existing brain abnormalities may increase the susceptibility to febrile seizures. Both these situations could eventually lead to epilepsy. But it will take more time for the study to confirm this, especially as it usually takes between 8 and 11 years for TLE to develop following FSE.

Temporal lobe epilepsy can cause memory loss, and neuroimaging of adults with temporal lobe epilepsy have sometimes revealed shrinkage and cell loss within the temporal lobe and hippocampus. Many adults with the disorder also report a history of FSE.

If MRI and EEG findings associated with FSE ultimately do correlate with epilepsy, they could be used to identify kids who are at risk and who might benefit from research on preventative therapies for epilepsy.

FEBSTAT is supported by grant NS043209 to Dr. Shinnar. Data from children with simple febrile seizures were taken from a study led by Dale C. Hesdorffer, Ph.D., of Columbia University in New York. That study ended in 2004, and was supported by grant HD036867 from NIH's Eunice Kennedy Shriver National Institute of Child Health and Human Development.

References:

1. M. J. Berg, B. Abou-Khalil. Childhood febrile status epilepticus: Chicken or egg? Does it matter? Neurology, 2012; 79 (9): 840 DOI: 10.1212/WNL.0b013e3182684559
2. S. Shinnar, J. A. Bello, S. Chan, D. C. Hesdorffer, D. V. Lewis, J. MacFall, J. M. Pellock, D. R. Nordli, L. M. Frank, S. L. Moshe, W. Gomes, R. C. Shinnar, S. Sun. MRI abnormalities following febrile status epilepticus in children: The FEBSTAT study. Neurology, 2012; 79 (9): 871 DOI: 10.1212/WNL.0b013e318266fcc5