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Original Article

Imaging and cytological analysis of 92 patients

with Japanese encephalitis

Qi Meng, Yue‑Li Zou, Hui Bu, Jun‑Ying He
Department of Neurology, Second Hospital of Hebei Medical University, Shijiazhuang 050000, Hebei, China.

ABSTRA CT

Aim: Japanese encephalitis (JE) is caused by a mosquito-borne flavivirus and demonstrates high mortality and serious sequelae.
Imaging and cytological examinations are important for the diagnosis of JE. We performed this study to analyze the imaging and
cytological characteristics of JE. Methods: This study enrolled 92 JE patients with 108 cerebral spinal fluid (CSF) samples. Diagnosis
was based on clinical features and positive immunoglobulin M antibodies against JE virus, which were measured using enzyme-linked
immunosorbent assay. All patients received detailed neurological examinations, relevant cerebrospinal fluid tests, and brain
neuroimaging (computed tomography, magnetic resonance imaging, or both). Results: Prominent involvement in the hippocampus
was observed in 10 patients on neuroimaging, in addition to classic involvement in the thalamus and basal ganglia. Lumbar puncture
pressure was normal in 61 CSF samples. White cell count increased in 81.19% of CSF samples, 67.65% and 83.33% of CSF samples
demonstrated normal chloride and glucose concentrations, respectively, and 82.52% of CSF samples demonstrated > 0.4 g/L protein
content. JE patients demonstrate mixed-cell reaction on cerebrospinal fluid cytology in the early phase, which subsequently mainly
develop as mainly lymphocyte reaction or typical lymphocyte reaction. Conclusion: JE imaging is characterized by bilateral thalamic
involvement, and the basal ganglia and hippocampus are also commonly affected. The mixed-cell reaction in JE lasts longer than in
general viral encephalitis. This may facilitate the differential diagnosis of JE.

Key words: Cerebrospinal fluid, cytology, Japanese encephalitis, neuroimaging

INTRODUCTION decreased due to the wide application of the JE
vaccine, though outbreaks still occur in some districts
and the number of adult infections is increasing. [7]
Japanese encephalitis (JE), which is caused by infection
with the JE virus (JEV), is one of the most important Bilateral thalamic lesions developed in endemic areas
viral encephalitis in the world, especially in East and during susceptible seasons should be considered as
encephalitis. Cytological analysis of the cerebrospinal
Southeast Asia. Approximately 35,000–50,000 people fluid (CSF) may reflect the clinical course of JE. Here, we

develop JE each year, demonstrating annual mortality analyze the radiological and cytological features of JE.
of 10,000–15,000. [1-3] About one-third of patients die,
and half of all survivors develop severe sequelae. [4-6] JE
is characterized by high fever, conscious disturbance, METHODS
seizures, focal neurological deficit, signs of meningeal
irritation, etc. JE is regarded as a pediatric disease in This study enrolled 92 JE patients who were diagnosed and
treated at the Second Hospital of Hebei Medical University
endemic areas. The morbidity of JE has substantially between August 2013 and October 2013. Diagnosis
was positive confirmation of immunoglobulin M (IgM)
antibodies to JEV in sera using IgM antibody capture
Access this article online
enzyme-linked immunosorbent assay by the center for
Quick Response Code: disease control and prevention in Hebei province. All
Website:
www.nnjournal.net CSF samples were examined at Second Hospital of Hebei
Medical University to determine the cellular, glucose,
DOI: protein, chloride, and cytological characteristics. Ethics
10.4103/2347-8659.135574 approval was given by the review board of the Second
Hospital of Hebei Medical University.

Corresponding Author: Dr. Jun‑Ying He, Department of Neurology, Second Hospital of Hebei Medical University, 215 Heping
West Road, Shijiazhuang 050000, Hebei, China. E‑mail: hyj_zn@126.com

Neuroimmunol Neuroinflammation | Volume 1 | Issue 1 | June 2014 29