Epstein-Barr Virus-associated Encephalitis and Lumbosacral Radiculitis, Evolved to Normal Pressure Hydrocephalus in an Immunocompetent Adult: A Case Report

Background Epstein-Barr virus (EBV) rarely causes central nervous system (CNS) infection in immunocompetent adults. EBV encephalitis is typically monophasic, with viral clearance expected. Reports of multiphasic EBV-related CNS disease with persistent infection are exceptionally scarce. Case Presentation: A previously healthy adult presented with acute EBV meningoencephalitis confirmed by cerebrospinal fluid (CSF) analysis (EBV DNA positive) and MRI (left frontal FLAIR hyperintensity), manifesting as aphasia and fever. Initial treatment with antivirals, moderate-dose glucocorticoids, and intravenous immunoglobulin (IVIG) resolved encephalitis. However, the patient subsequently developed acute demyelinating lumbosacral radiculitis (back pain, lower limb paralysis, albumin-cytological dissociation in CSF, EMG-confirmed demyelination), despite negative autoantibody panels. Symptoms resolved after a second IVIG course. Long-term follow-up revealed persistent EBV DNA and elevated protein in CSF for over 3 months, prompting extended antiviral and low-dose glucocorticoid maintenance therapy. Although no encephalitis recurrence occurred, the patient later developed normal pressure hydrocephalus (NPH), receiving lumbo-peritoneal shunting. Residual functional impairment persisted. Conclusions This case illustrates a unique, multiphasic EBV CNS infection involving sequential meningoencephalitis and radiculitis, with persistent intrathecal EBV replication and chronic neuroinflammation culminating in NPH. It challenges the paradigm of EBV encephalitis as solely monophasic and highlights the potential role for sustained immunomodulation alongside antivirals. Persistent CSF EBV and inflammation warrant vigilant monitoring for late complications like NPH.