MRI, EEG shed light on epilepsy risk in children following febrile seizures

A combination of MRI and electroencephalography (EEG) findings following fever-induced seizures could identify children at risk for subsequent epilepsy, according to a study published online Nov. 7 in Neurology.

Febrile seizures affect 3-4 percent of all children. They are usually benign, but prolonged febrile seizures could foreshadow an increased risk of epilepsy later in life.

"While the majority of children fully recover from febrile status epilepticus (FSE), some will go on to develop epilepsy. We have no way of knowing yet who they will be," Shlomo Shinnar, MD, PhD of Montefiore Medical Center in New York City, said in a release. "Our goal has been to develop biomarkers that will tell us whether or not a particular child is at risk for epilepsy. This could in turn help us develop strategies to prevent the disorder."

To that end, the Consequences of Prolonged Febrile Seizures in Childhood (FEBSTAT) study focused on the risk of temporal lobe epilepsy associated with FSE, which involves seizures lasting 30 minutes or more. Shinnar and colleagues looked at MRI and EEG findings gathered from children within 72 hours of a febrile seizure. Children were enrolled from 2003 to 2010 at five sites. In addition to the MRI and EEG, children also underwent a blood test and neurological exam.

Results showed that of 191 children with FSE, 11.5 percent had signs of hippocampal injury on MRI and 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—with only 2.1 percent of the 96 children with such seizures demonstrating developmental abnormalities.

Nearly half of the children with FSE had abnormal EEG findings, and children with evidence of acute brain injury after FSE were more than twice as likely to have abnormal EEG findings.

Brain scans of adults with temporal lobe epilepsy sometimes reveal shrinkage and cell loss within the hippocampus and temporal lobe. Many with the disorder also report a history of FSE, according to the researchers.

The results suggest that prolonged febrile seizures injure the brain in some children, while for others, pre-existing abnormalities could make the brain susceptible to febrile seizures. Shinnar said either scenario could lead to epilepsy, but that has yet to be confirmed.