[A cause of acute encephalitis: primary infection due to Epstein-Barr virus]

The neurologic complications of Epstein-Barr virus (EBV) primary infection are frequently overlooked, yet EBV is responsible for some cases of acute encephalitis. We report on a case of an infant with acute brain-stem encephalitis during EBV primary infection.

A 22-month-old boy was admitted to the hospital for acute neurological symptoms. Initially, he presented ataxia and dysphagia. During the first days, his neurological status worsened with loss of consciousness requiring ventilatory support. A progressive improvement appeared after a 1 week course. One month later, a moderate ataxia was still noted, but 3 months later, the clinical examination was normal. The neuroradiological explorations revealed damage of the white matter, with high T2-weighed signal on the first brain magnetic resonance imaging. One month later, the control magnetic resonance imaging was normal. The diagnosis of EBV encephalitis was based upon the exclusion of other possible causes and positive serology for EBV, consistent with acute primary infection.

EBV infection should be looked for during the etiologic work-up of an acute encephalitis. The different cases reported in the literature show a favorable initial outcome, but neurological relapse and sequelae are possible. No specific treatment is effective.