to the editor: It has been estimated that less than 1 percent of persons infected with Epstein-Barr virus (EBV) have central nervous system complications. These complications include encephalitis, Guillain-Barré syndrome, aseptic meningitis, facial palsy, transverse myelitis and Bell's palsy.^1–3 EBV encephalitis is generally self-limited without sequelae but may produce cerebellar ataxia.^4,5 I would like to present a report on a child with encephalitis and cerebellar ataxia from EBV infection.

A two-year-old girl presented with a generalized seizure with tonic-clonic movements of all extremities. She was found to be in status epilepticus in the emergency department and was given 0.25 mg per kg of diazepam (Valium) intravenously, which stopped the convulsions. She responded to painful stimulation and was aroused by stimulation by her mother. Blood chemistries were within normal limits. A blood culture was obtained. A cerebrospinal fluid analysis was performed, which showed clear colorless spinal fluid with a glucose level of 66 mg per dL (normal range: 40 to 70 mg per dL), protein of 43 mg per dL (normal range: 15 to 45 mg per dL), red blood cell count of 10 per mm³, white blood cell count of 70 per mm³ with 50 percent lymphocytes. The electroencephalogram and computed tomographic scan were within normal limits.

The child became more responsive and the postictal state cleared, but she was ataxic with falling to her right side. The Bactogen panel for Haemophilus influenzae, Neisseria meningitidis and Streptococcus pneumoniae was negative. She was discharged and followed through outpatient office visits. Complete blood count on discharge revealed a white blood cell count of 11,400 per mm³, with 36 percent lymphocytes and 14 percent atypical lymphocytes. Blood and spinal fluid cultures were negative for growth. The patient was extremely fatigued and would sleep for long periods after participating in activities. An EBV antibody profile was submitted. Spinal fluid polymerase chain reaction results for herpes types 1 and 2 were negative. Two weeks after discharge, she appeared normal with her gait disturbance resolved. The EBV profile was positive, showing a viral capsid antigen (VCA)–IgM value of 20 arbitrary units (AU) with a positive reading defined as a value of 20 AU or greater; a VCA–IgG value greater than 170 AU (positive defined as a value of 20 AU or greater) and a nuclear antigen antibody greater than 200 AU (positive defined as a value of 20 AU or greater). The patient continues to do well at follow-up.

Because there are few distinguishable clinical features, a clinical diagnosis of viral encephalitis may be difficult to make. Evaluation of the cerebrospinal fluid of a child with encephalitis will typically show a lymphocytic pleocytosis with mild protein elevation and normal glucose level.³ Altered consciousness and generalized seizure are the most common presenting symptoms of postinfectious encephalitis.⁵ Cerebellar ataxia may occur with or follow viral infections of the nervous system. Most patients with neurologic complications recover within several months.²

It is possible that invasion of the nervous system by EBV-infected cells may commonly occur but only occasionally produce significant neurologic disease. The mechanism of injury may be the result of infected cells infiltrating neural tissue or inducing an inflammatory reaction that secondarily causes symptoms.^3,6