Acute Necrotizing Encephalopathy in Korean Infants and Children: Imaging Findings and Diverse Clinical Outcome

OBJECTIVE The purpose of our study was to describe acute necrotizing encephalopathy in Korean infants and children, and we sought to evaluate the prognostic factors. MATERIALS AND METHODS Acute necrotizing encephalopathy was diagnosed in 14 Korean infants and children. We retrospectively analyzed the neuroimaging findings including the follow-up changes. The clinical course of the disease was graded, and we evaluated prognostic factors including age, serum level of the aminotransferase, hemorrhage, and localized atrophy of the brain. RESULT This encephalopathy predominantly affected the bilateral thalami (n = 14), pons (n = 12), and midbrain (n = 10) in a symmetrical pattern. Hemorrhage was observed in eight patients (57%). On the follow-up images (n = 12), the brain lesions were reduced in extent for all patients, and generalized atrophy was seen in six patients. Localized tissue loss was observed in five patients and a complete resolution occurred for one patient. All the patients survived and two recovered completely; mild (n = 6) to severe (n = 6) neurological deficits persisted in the remaining 12 patients. The significant prognostic factors identified in this study were the presence of hemorrhage (p = 0.009) and localized atrophy (p = 0.015). CONCLUSION Acute necrotizing encephalopathy in Korean patients showed the characteristic patterns of the post-infectious encephalopathy as described in the literature. The high survival rate and the relatively favorable clinical course observed for the present study suggest a more diverse spectrum of disease severity than was previously described. The presence of hemorrhage and localized tissue loss on MR images may suggest a poor prognosis.