[A child with inexplicable alteration of consciousness].

A 4-year-old girl presented with an alteration of consciousness and absence of speech after a short period of vomiting, diarrhoea and fever. MRI of the brain revealed a focal lesion in the splenium of the corpus callosum. Rotavirus was detected in the faeces. We concluded that the rotavirus infection had caused mild encephalopathy with a reversible splenial lesion.