[PS18-3B-1] Acute Infantile Encephalopathy Predominantly Affecting the Frontal Lobes (AIEF)
Acute infantile encephalopathy predominantly affecting the frontal lobes (AIEF) is one subtype of acute encephalopathy with biphasic seizures and late reduced diffusion, which category was firstly reported as acute encephalopathy with febrile convulsive status epilepticus in Japan. AIEF develops 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 is one of the most characteristic features in AIEF. Radiological studies show edematous changes appeared predominantly in the frontal lobes at the several days after the onset, those of which are detected sensitively on diffusion-weighted MRI. Secondary atrophic changes as well as increased intensity on T2-weight MRI are seen in the frontal lobes thereafter. Cerebral perfusion commonly increase in the frontal lobes at the onset, where one is attenuated in the later period. Neurological manifestations also suggest the frontal lobe dysfunction: a lack of spontaneity and regression of verbal functions which become evident after the recovery of consciousness. Verbal functions are well correlated with recovery of cerebral perfusion in the frontal lobes. Impulsive behaviors are commonly found in the later period. 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.