Mild Encephalopathy/Encephalitis With Reversible Splenial Lesion Associated With Meningitis Related to Mumps Disease: An Unusual Presentation in a Male Adult.

Mild encephalitis/encephalopathy with reversible splenial lesion (MERS) is characterized by mild neurological manifestations associated with spontaneously reversible lesions of the splenium of the corpus callosum. While various conditions and diseases can trigger MERS, infectious causes predominate, with mumps being notably linked to MERS in the pediatric population. Although rare in adults, there are sporadic case reports associating mumps with MERS. Here we report a 23-year-old male patient with a typical presentation of mumps who presented with meningeal syndrome, dizziness, seizures, and right orchitis. Brain MRI showed classic findings of MERS syndrome while cerebrospinal fluid analysis demonstrated lymphocytic pleocytosis. Our patient had a confirmed diagnosis of mumps disease with multiple complications, including MERS, meningitis, and orchitis, and was managed with symptomatic medications and antiviral therapy. Subsequently, there was a gradual resolution of these manifestations and the outcome was favorable, with no residual sequelae.