Abstracts

Rationale: The aim of this presentation is to exhibit the subtype of acute encephalopathy, Acute Infantile Encephalopathy Predominantly Affecting the Frontal Lobes (AIEF), which is firstly reported as acute encephalopathy with febrile convulsive status epilepticus in Japan.  Methods: Our clinical experiences of 10 patients as well as the results of national surveillance allow us to  established the diagnosic criteria of AIEF. Results: AIEF developed in infancy, mostly 1 or 2 years of age. Boys and girls were equally affected. Manifestations at the onset were convulsive status epilepticus and prolonged coma with hyperpyrexia mostly due to viral illness. The dysfunction in the frontal lobes was one of the most characteristic features in AIEF. Radiological studies showed edematous changes appeared predominantly in the frontal lobes at the several days after the onset, those of which were detected sensitively on diffusion-weighted MRI. Secondary atrophic changes as well as increased intensity on T2-weight MRI were seen in the frontal lobes thereafter. Cerebral perfusion commonly increaseed in the frontal lobes at the onset, where one was attenuated in the later period. Neurological manifestations also suggested the frontal lobe dysfunction: a lack of spontaneity and regression of verbal functions which became evident after the recovery of consciousness. Verbal functions were well correlated with recovery of cerebral perfusion in the frontal lobes. Impulsive behaviors were commonly found in the later period. Conclusions: It still remains unknown why the frontal lobes are predominantly affected. Studies on the excitatory and inhibitory receptors as well as their transporters in the developing human brain may help understand the mechanism for this specific distribution of AIEF, because the expression of these receptor subunits shows age-dependent and region-specific changes Funding: nothing