Two Cases of Acute Encephalopathy with Symmetrical Low Density Areas in Bilateral Thalami in Siblings

Lee, Soon Young; Lee, Woo Jin; Lee, Ji Eun; Kim, So Yeon; Lee, Jong Ho; Lee, Seung Jae

Abstract

When neurologic clinical manifestation suggests encephalitis but inflammation of brain has not occurred, the condition is identified by the less specific term encephalopathy. A strange type of acute encephalopathy, which is characterized by symmetrical low density areas in both thalami on brain computed tomography (CT) images, has been reported in Japan and Taiwan. This type of acute encephalopathy usually occurs in infants and young children without sexual predilection and is preceded by fever and symptoms of upper respiratory infection for several days. These symptoms are followed by the rapid evolution of stupor and coma, associated with generalized seizures and decorticated and decerebrated rigidity without focal neurologic or meningeal signs. Brain CT images demonstrates symmetrical low density areas in both thalami. Because it is preceded by fever and symptoms of upper respiratory infection and pathologic finding shows necrosis, petechiae, and marked congestion of the veins and capillaries suggesting noninflammatory vascular changes, it may be a postviral or postinfectious brain disorder, characterized by the distribution of the lesions. We experienced two cases of this type of acute encephalopathy in siblings, who showed symmetrical low density areas in both thalami on brain CT images and report these cases with a brief review of related literatures.