Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 59, Num. 4, 2011, pp. 605-607

Neurology India, Vol. 59, No. 4, July-August, 2011, pp. 605-607

Case Report

Epstein Barr virus encephalitis: Clinical diversity and radiological similarity

J Kalita, PK Maurya, B Kumar, UK Misra

Centre of Excellence of Encephalitis Research, Department of Neurology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
Correspondence Address: U K Misra, Department of Neurology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raebareily Road, Lucknow - 226 014, Uttar Pradesh, India, drukmisra@rediffmail.com

Date of Submission: 03-Jun-2011
Date of Decision: 28-Jun-2011
Date of Acceptance: 06-Jul-2011

Code Number: ni11180

PMID: 21891943

DOI: 10.4103/0028-3886.84347

Abstract

Keywords: Chorea, electroencephalogram, encephalitis, Epstein Barr virus, movement disorder, magnetic resonance imaging, outcome, visual loss

Introduction

Epstein Barr virus (EBV) is a double-stranded herpes virus affecting B lymphocytes and epithelial cells. A large number of asymptomatic adults show EBV seropositivity. In children above 10 years of age, EBV infection results in infectious mononucleosis, fever, skin eruption, atypical monocytosis, thrombocytopenia, and liver dysfunction. Neurological manifestations of EBV infection include encephalitis, meningitis, cerebellitis, acute disseminated encephalomyelitis (ADEM), transverse myelitis and radiculopathy. ^[1] In regions endemic to encephalitis or during epidemics of encephalitis a number of sporadic encephalitis cases tend to be overlooked. The characteristic radiological findings often help in suggesting the possible etiology of encephalitis, e.g. frontotemporal involvement in herpes simplex encephalitis; thalamus, basal ganglia and brainstem involvement in Flavivirus encephalitis. ^[2],[3] Of the 41 patients with acute encephalitis seen during 2007, in two patients the encephalitis was due to EBV infection. In this communication we highlight the clinical diversity and typical magnetic resonance imaging (MRI) findings in these two patients.

Case Reports

Case 1

A six-year-old boy developed fever of 39°C for 10 days. He had irrelevant talk and hallucination on Day 4 and unconsciousness with extensor posturing on Day 7 of illness. Examination revealed normal vitals except for tachycardia and right conjunctival hemorrhage. There was no anemia, lymphadenopathy, or hepatosplenomegaly. On neurological examination he was drowsy, unresponsive to verbal command and had extensor posturing to pain. He had severe neck retraction and decerebration. Pupils were semidilated and reacting to light. He had severe spasticity and hyperreflexia. By Day 15, his sensorium started improving and extensor posturing reduced. The child was crying all the time and complained of blindness.

Investigations

Investigation revealed total white cell count 2368/ mm ³ with 75% polymorphs, 25% lymphocytes and no atypical cells, hemoglobin 10.3 g/dl, platelet count 27000/ mm ³ , normal blood biochemistry; and serum CK 3500 (MM 2250) U/L. Cranial MRI revealed bilateral parieto-occipital hyperintensity in T2 and FLAIR (fluid attenuation inversion recovery) sequence [Figure - 1]a which was isointense on T1. Cerebrospinal fluid (CSF) opening pressure was high and CSF analysis revealed 155 cells/ mm ³ (45% polymorph), 64.6 mg/dl protein and 43 mg/dl sugar. Serum IgM ELISA was negative for dengue and CSF IgM ELISA was negative for Japanese encephalitis (JE). CSF polymerase chain reaction (PCR) was negative for HSV1 but positive for EBV [Figure - 1]c. Electroencephalogram (EEG) showed delta slowing. He received intravenous acyclovir 10 mg/kg eight-hourly for 14 days. At the time of discharge, he was conscious and cooperative although blind. At three months' follow-up his vision improved to 6/12 in the right and 6/24 in the left eye. Severe spasticity persisted although he could stand with support. At 18 months' follow-up, he appeared cognitively normal but his visual and motor deficit remained the same. Repeat MRI at two months revealed reduction in signal changes [Figure - 1]b.

Case 2

An 11-year-old girl presented with fever and vomiting for 16 days. On Day 2, she had right focal seizure with secondary generalization, following which her consciousness deteriorated. Subsequently, she started having extensor posturing. On Day 16 of illness, vitals were normal, but she was dehydrated. There was no rash, lymphadenopathy or hepatosplenomegaly. She opened eyes spontaneously and responded by limb flexion to pain but no verbalization. Eyes were deviated down and in and there was left facial nerve palsy. There was spastic quadriparesis, more marked on the left side and muscle power was grade 3/5 with reduced deep tendon reflexes. On Day 23, she developed trunk, limb and tongue dystonia associated with choreiform movement in the upper limbs.

Investigations

Investigation revealed total white blood cell count 6600/ mm ³ with 73% polymorph, 22% lymphocyte, 1% eosinophil and 4% monocyte, hemoglobin 7.99 g/dl, platelet count 280000/ mm ³ , normal blood biochemistry, and serum CK (creatine kinase) 319 U/L. EEG revealed theta slowing. Cranial MRI revealed hyperintensity in bilateral parieto-occipital region in FLAIR image. CSF protein was 37 mg/ dl, sugar 57 mg/dl and 10 lymphocytes/mm ³ . CSF IgM ELISA was negative for JE, PCR was negative for herpes simplex virus I and positive for EBV. She received acyclovir 10 mg/kg eight-hourly for 14 days. Repeat MRI at one month was normal. At three months follow-up, she did not improve significantly, her dystonia, chorea and spasticity of lower limbs persisted and she was dependent for activities of daily living. At 18 months, her choreiform movements disappeared but mild dystonia and spasticity persisted. She was able to do her daily activities but could not go back to her school. The salient points in clinical and MRI findings of both the patients are summarized in the [Table - 1].

Discussion

Both the patients with EBV encephalitis presented with a clinical picture of acute encephalitis; however, the MRI finding in the first week revealed fronto-parieto-occipital involvement in the first patient and parieto-occipital involvement in the second patient. Such MRI features have been reported in EBV and based on these findings, we confirmed the diagnosis of EBV encephalitis by PCR. In the first patient, the splenium of the corpus callosum was also affected. Similar MRI features have been reported in hypoglycemia, hypoxia, prolonged seizures and electrolyte imbalance; however, in our patients these possibilities were excluded. ^[4],[5],[6] The MRI lesions disappeared in one and regressed in the other. The patient with normal repeat MRI study had severe pyramidal and extrapyramidal findings highlighting the limitation of clinico-radiological correlation. We did not find any abnormality in the basal ganglia region to account for the movement disorder, which is a more common feature of arboviral encephalitis. High frequency of Parkinsonian features and dystonia has been reported in JE. ^[7] In a patient with EBV encephalitis, Parkinsonian features such as rigidity, tremor, bradykinesia, staring eyes and perceptual abnormality were reported. Although the MRI was normal in this patient SPECT (single photon emission computed tomography) showed diminished perfusion of the right caudate nucleus. ^[8] In our patients, we did not undertake SPECT studies which could have revealed the functional changes not seen on MRI. In the first patient, the cortical blindness was the most important symptom which persisted for one month and gradually improved. A review of the literature did not reveal any reference to cortical blindness in EBV infection; however, involvement of the occipito-parietal area can very well explain the visual deficit.

Prognosis of EBV encephalitis is supposed to be good and the radiological changes are typically reversible. Though our patients revealed improvement on repeat MRI study, neurological deficits persisted in both the patients. Long-term follow-up revealed regression of movement disorder and visual deficit but spasticity persisted. In JE also, movement disorders have been reported to improve over time. ^[7]

We draw attention to the typical parieto-occipital cortical involvement in EBV encephalitis which may help in suggesting the diagnosis; however, it needs to be verified in a larger study. Blindness, movement disorders and spasticity underscore the diverse clinical presentation of EBV encephalitis.

Acknowledgment

We thank Mr. Rakesh Kumar Nigam for secretarial help.

References

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