Radiological features of herpetic encephalitis in children

Background and Objectives Nonspecific clinical manifestations and unclear radiological features may delay treatment initiation in pediatric Herpes simplex encephalitis (HSE). Aim of this study is to analyze the clinical and radiologic features of the disease. Methods Clinical, laboratory, and magnetic resonance imaging (MRI) data were obtained retrospectively from a group of 37 hospitalized pediatric patients older than two months and with a polymerase chain reaction-confirmed HSE diagnosis. Clinical severity (i.e, mechanical ventilatory support), and outcome at discharge (i.e., pediatric modified Rankin Scale, ped-mRS) were also assessed. Results Median age was 14 months [interquartile range: 10-36]. All patients survived, 15 (41%) had complete recovery (i.e., ped-mRS=0) and 10 (27%) had significant residual disability at discharge (i.e., ped-mRS>3). Brain MRI was obtained in 31 patients. T2-hyperintense lesions were usually bilateral (28, 90%) and multifocal (30, 97%). Hemorrhage and mass effect were observed in 13 (42%) and 14 (48%) patients, respectively. Parenchymal lesions involved temporal lobes (94%), insula (90%), parietal lobes (84%), and frontal lobes (61%). Occipital lesions were rare. In multivariable binary logistic regression models the presence of altered consciousness was associated with mechanical ventilation (odds ratio [OR]=8.2, Nagelkerke R2=0.22), while the involvement of the occipital lobe (OR=7.8) and the administration of vasopressors (OR=12.1) were independent predictors of poor outcome (Nagelkerke R2=0.41). Conclusions Brain MRI is useful for diagnosis and outcome assessment in pediatric HSE. Radiological patterns with common frontotemporal involvement overlap adults, but multifocal and parietal lobe abnormalities are seen as well.