[Infection-related acute encephalopathy: CT scan/MRI finding, laboratory examination and prognosis]

CT/MRI findings, laboratory examinations and prognoses of 42 patients with acute encephalopathy (AE) (Japan Coma Scale > or = 200) were reported. 1. Findings on CT/MRI were divided into the following 7 categories: Group 1 (normal), Group 2 (CT/MRI looked normal in acute phase, but brain atrophy developed and progressed slowly by weeks or months), Group 3 (CT/MRI looked normal within a few days after the onset of AE, but cortical laminar necrosis developed at 4-5 days after the onset), Group 4 (marked brain edema developed within 2 days after the onset of AE), Group 5 (AE with symmetric thalamic lesions), Group 6 (symmetric pallidum, lesions on MRI which appeared after brain edema disappeared), and Group 7 (the brain shrinked during acute phase, which normalized on the follow up CT/MRI). 2. Serum AST elevated in approximately 50% of the patients with AE. Sixty percent of them exhibited DIC, whose prognoses were poor. Cerebrospinal fluids (CSF) neopterin (NP) and/or interleukin (IL)-6 were elevated in all the 8 patients examined. In the two cases whose serum NP and IL-6 were measured at the same time, their values in the CSF were higher than those in the serum in one case, and almost the same in the other. In a patient with a condition mimicking hemorrhagic shock and encephalopathy, serum IL-6 concentration was very high (94,000 pg/ml). 3. Mild hypothermia (around 34 degrees C) combined with methylprednisolone pulse therapy was excellently effective on AE. A 6-year-old boy exhibited tonsillar herniation at admission recovered well to be able to run. 4. Differentiation between Reye syndrome and HSE, and the pathogenesis of AE were also discussed.