PET Scans Offer Clues into Fever-Induced Epilepsy in Children

Sudden, catastrophic childhood epilepsy, particularly in the case of fever-induced refractory epileptic encephalopathy in school-age children (FIRES), is a parent's worst nightmare. Whereas not much is known about the disorder, new findings revealed that positron emission tomography (PET) imaging scans could provide an evaluation of cognitive dysfunction of FIRES, its evolution, and further prognosis.

FIRES, a recently named condition, occurs in previously healthy children who, after a brief fever, experience acute seizures that are resistant to medication and last for several weeks. After the seizures stop, children are left with severe cognitive dysfunction, chiefly involving language, memory, and behavior.

The study, published in the January 2011 issue of the Journal of Nuclear Medicine, was conducted with eight patients diagnosed with FIRES. The patients were given a neuropsychologic evaluation, a brain magnetic resonance imaging (MRI) scan, and an ¹⁸F-FDG (fluorodeoxyglucose) PET scan. Severe cognitive dysfunction was noted, and while the MRI scans showed no abnormalities for the patients, the PET scans reported considerable cognitive impairment.

Researchers compared the FIRES patients with a pseudo-control group of epilepsy patients with normal MRI and PET scan results. Employing statistical parametric mapping, an objective approach to analyzing brain activity, the study revealed that the brain dysfunction was related to the epilepsy in the FIRES patients.

"The fact that the dysfunctional network is superimposed over the epileptic network is a strong argument that FIRES is the cause of cognitive deterioration in these previously normal children. Moreover, localizing such a dysfunction may help to specify the readaptation more accurately,” said Catherine Chiron, MD, PhD, pediatric epileptologist and head of the Research Program on Epilepsy at Hospital Necker--Enfants Malades Paris (France), and one of the authors of the study. "These findings may open the way for using ¹⁸F-FDG PET more extensively and more accurately in pediatric imaging, as this methodology allows us to investigate not only unilateral but also bilateral diseases, and to interpret PET images in an objective and sensitive manner.”

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Hospital Necker--Enfants Malades Paris