Mild Encephalopathy with a Reversible Splenial lesion, a differenzial diagnosis to consider in children 
Background 
Mild Encephalopathy with a Reversible Splenial lesion (MERS) is an uncommon clinical-radiological entity characterized by magnetic resonance imaging (MRI) findings of a reversible lesion in the splenium of corpus callosum associated with significant neurological manifestation of encephalopathy.  We report three cases of children with different clinical and radiological presentation, associated to an infection.
Case Presentation Summary 
The first case is a 14 years old girl admitted for malaise, fever, headache and later a worsening of neurological aspect with confusion, psychomotor crisis, urinary and fecal retention. Laboratory tests showed hyponatremia and HHV6 infection. Anomalies were evident to electroencephalogram (EEG) and somatosensory evoked potentials (SEEP). The brain MRI showed lesions in the corpus callosum at the splenium level.
The second patient is a 3 years old boy admitted for fever, hyponatremia and hypoglicemia. Neurological examination showed poor mental status, lethargy with absence of lower limb tendon reflexes. Cranial MRI showed a focal lesion in the splenium of the corpus callosum. The electroencephalogram (EEG) revealed diffuse slow waves. Pharyngeal swab PCR was positive for Influenza B. 
The third case is a 11 years old female admitted to our department because of fever, strabismus of the left eye and diplopia. Neuro-ophtalmologic evaluation was normal. Cranial MRI revealed the presence of high signal lesion in the splenium of corpus callosum. The laboratory tests showed HHV6 infections. 
Learning Points/Discussion 
MERS is an important differential diagnosis to consider in children presenting with acute encephalopathy/encephalitis. In our experience, patient’s symptoms recovered quickly and the splenial lesion disappeared, as described in literature. MERS in clinical practice is very low, but knowledges about its existence are essential to suspect and manage it.

ESPID 2018