A Feasibility Study of Quantifying Longitudinal Brain Changes in Herpes Simplex Virus (HSV) Encephalitis Using Magnetic Resonance Imaging (MRI) and Stereology.

Kumar Das,Girvan Burnside,Rishma Vidyasagar,Tom Solomon,Neil Roberts,On Behalf Of Enceph Uk Study Group ,Simon S. Keller,Michael Griffiths,Laura M. Parkes,Sylviane Defres,Michael Kopelman

doi:10.1371/journal.pone.0170215

Abstract

ObjectivesTo assess whether it is feasible to quantify acute change in temporal lobe volume and total oedema volumes in herpes simplex virus (HSV) encephalitis as a preliminary to a trial of corticosteroid therapy.MethodsThe study analysed serially acquired magnetic resonance images (MRI), of patients with acute HSV encephalitis who had neuroimaging repeated within four weeks of the first scan. We performed volumetric measurements of the left and right temporal lobes and of cerebral oedema visible on T2 weighted Fluid Attenuated Inversion Recovery (FLAIR) images using stereology in conjunction with point counting.ResultsTemporal lobe volumes increased on average by 1.6% (standard deviation (SD 11%) in five patients who had not received corticosteroid therapy and decreased in two patients who had received corticosteroids by 8.5%. FLAIR hyperintensity volumes increased by 9% in patients not receiving treatment with corticosteroids and decreased by 29% in the two patients that had received corticosteroids.ConclusionsThis study has shown it is feasible to quantify acute change in temporal lobe and total oedema volumes in HSV encephalitis and suggests a potential resolution of swelling in response to corticosteroid therapy. These techniques could be used as part of a randomized control trial to investigate the efficacy of corticosteroids for treating HSV encephalitis in conjunction with assessing clinical outcomes and could be of potential value in helping to predict the clinical outcomes of patients with HSV encephalitis.

Highlights

Herpes simplex virus (HSV) encephalitis is the most common infectious cause of sporadic encephalitis [1,2,3,4]
The study analysed serially acquired magnetic resonance images (MRI), of patients with acute HSV encephalitis who had neuroimaging repeated within four weeks of the first scan
Temporal lobe volumes increased on average by 1.6% (standard deviation (SD 11%) in five patients who had not received corticosteroid therapy and decreased in two patients who had received corticosteroids by 8.5%

Summary

Introduction

Herpes simplex virus (HSV) encephalitis is the most common infectious cause of sporadic encephalitis [1,2,3,4]. It leads to haemorrhage, necrosis and extensive oedema, characteristically of the medial temporal lobes, and extends to affect other limbic areas including insular, cingulate and inferolateral frontal cortices [5]. Necrosis and extensive oedema, characteristically of the medial temporal lobes, and extends to affect other limbic areas including insular, cingulate and inferolateral frontal cortices [5] These changes are best visualized by use of Magnetic Resonance Imaging (MRI) [6]. Survivors are left with a variety of sequelae including personality and behavioural changes, seizures, dysphasia and neuropsychological sequelae including memory problems [12,13]

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