[P2-22] Six cases of mild acute encephalitis/encephalopathy showing paradoxical arousal responses in the electroencephalogram
[Introduction]
Acute encephalitis/encephalopathy (AE) is a syndrome that shows seizures or prolonged disturbance of consciousness after some triggers such as infection. We experienced six cases of mild AE that showed typical electroencephalographic sign, paradoxical arousal responses (PAR), that means slowing of background activity by any awakening stimulation.
[Methodology]
Among AE cases in the single center between April 2012 and October 2015, we selected those cases that showed PAR in the electroencephalogram (EEG) with no sequelae. Patient profiles, symptoms, treatments, brain imagings and polymorphism of genes that have been reported as risk factors of AE were examined retrospectively.
[Results]
Six cases (three male, the mean age 54 months old) are selected. As the past or family history three cases had non-rapid eye movement sleep arousal disorders or delirium induced by fever. All cases showed somnolence or irritability that lasted for two to five days. Brain 99m Tc-ECD SPECT was taken in five cases, all of which showed the decrease of cerebral blood flow in retrosplenial region and visual cortex and four of which showed the decrease in the precuneus. Genetic testing was performed in five cases, four of which had the thermolabile F352C polymorphism of CPT2 gene.
[Discussion]
These six cases of mild AE showing PAR had common symptoms, SPECT findings and genetic background. Temporal dysfunction of medial parietooccipital cortex is suggested as the pathophysiological basis. Genetic thermolability of fatty acid metabolism may be one of the predisposing factors.
Acute encephalitis/encephalopathy (AE) is a syndrome that shows seizures or prolonged disturbance of consciousness after some triggers such as infection. We experienced six cases of mild AE that showed typical electroencephalographic sign, paradoxical arousal responses (PAR), that means slowing of background activity by any awakening stimulation.
[Methodology]
Among AE cases in the single center between April 2012 and October 2015, we selected those cases that showed PAR in the electroencephalogram (EEG) with no sequelae. Patient profiles, symptoms, treatments, brain imagings and polymorphism of genes that have been reported as risk factors of AE were examined retrospectively.
[Results]
Six cases (three male, the mean age 54 months old) are selected. As the past or family history three cases had non-rapid eye movement sleep arousal disorders or delirium induced by fever. All cases showed somnolence or irritability that lasted for two to five days. Brain 99m Tc-ECD SPECT was taken in five cases, all of which showed the decrease of cerebral blood flow in retrosplenial region and visual cortex and four of which showed the decrease in the precuneus. Genetic testing was performed in five cases, four of which had the thermolabile F352C polymorphism of CPT2 gene.
[Discussion]
These six cases of mild AE showing PAR had common symptoms, SPECT findings and genetic background. Temporal dysfunction of medial parietooccipital cortex is suggested as the pathophysiological basis. Genetic thermolability of fatty acid metabolism may be one of the predisposing factors.