HHV6-related mild encephalopathy with reversible splenial lesion (MERS) presenting with urinary and fecal retention in an Italian adolescent.

Mild encephalopathy with a reversible splenial lesion (MERS) is an uncommon clinico-radiological entity characterized by magnetic resonance imaging (MRI) findings of a reversible lesion in the splenium of corpus callosum associated with a significant neurological manifestation of encephalopathy. The majority of reported cases involve the Asiatic population and are closely associated with infection. We report the case of an adolescent with an HHV6-related MERS presenting with hyponatremia and urinary and fecal retention. To our knowledge, urinary retention is not a constant aspect of the disease and has rarely been described, while fecal retention has never been reported before. Despite the self-limiting nature of the disease, it is mandatory to suspect it for a faster diagnosis and it might be useful to know its rare occurrences in order to better understand its etiopathogenetic mechanisms.