Rotavirus-infected children with clinically mild encephalopathy with a reversible splenial lesion (MERS).

To cite: Yokoyama T, Yamada S, Doichi N, et al. BMJ Case Rep Published online: [please include Day Month Year] doi:10.1136/ bcr-2013-008644 DESCRIPTION A previously healthy 2-year-old boy presented to our hospital with seizure. He had fever, diarrhoea and vomiting for 2 days before admission. His seizure continued for 2 min and was accompanied by loss of consciousness and tonic seizure. His seizure spontaneously stopped and he fully recovered. He did not have Kernig’s sign or neck stiffness. Blood test and cerebrospinal fluid (CSF) analysis were normal. We made a diagnosis of simple febrile seizure. However, 20 h after admission, 2 min of tonic seizure recurred when he was crying. At the same time, rotavirus (RV) antigen was detected in his stool. These were some atypical findings which were different from typical simple febrile seizure that not tonic-clonic seizures but tonic seizure, occurrence of the seizure 2 days after the onset of the illness, and occurrence of the second seizure 20 h after the first seizure. So, he was diagnosed as possibly having encephalitis and we performed neuroimaging evaluation. Diffusion-weighted MRI of the brain showed an intensified signal in the splenium of the corpus callosum (figure 1A). Apparent diffusion coefficient (ADC) mapping showed decreased ADC values at the abnormality (figure 1B). We confirmed a diagnosis of RV infectionassociated clinically mild encephalopathy with a