Focal Glucose Hypermetabolism in Interictal State of West Syndrome

This report concerns two siblings from a tetrad, both of whom had West syndrome with atypical findings on positron emission tomography using [18F] fluorodeoxyglucose. One manifested periventricular leukoencephalopathy, and the other had periventricular leukoencephalopathy as well as porencephaly because of fetal distress and brain parenchymal hemorrhage in the neonatal period. They developed West syndrome at the age of 9 months. Fluorodeoxyglucose–positron emission tomography study performed after cessation of their seizures revealed an increase in glucose metabolism. The corresponding region presented low-level accumulation in [11C]flumazenil positron emission tomography. The patients remained seizure-free for more than 1 month, and their electroencephalograms only occasionally disclosed sporadic paroxysmal discharges. Because of the decreased density of benzodiazepine receptor in these lesions, the activity of the excitatory neuron system may overexpress that of the inhibitory neuron system, thus resulting in epileptogenesis of the lesions. It is suggested that fluorodeoxyglucose and flumazenil–positron emission tomography revealed functional abnormalities and that epileptogenesis of these patients is still active even when the patient is seizure-free and there are mild epileptogenic discharges on electroencephalogram.