VIRAL ENCEPHALITIS

DR.PRAVEEN NAGULA

INTRODUCTION

Acute febrile illness plus altered level of consiousness

Signs and symtpoms reflect the site of inflammation

Impossible to distinguish reliably on the clinical grounds alone one type from other.

Etiology

Sporadic cases -- immunocompetent patients HSV,VZV,EBV.

Epidemics – arbovirusesAlphavriuses – EEE ,western equine virusFlaviviruses – WNV,st louis encephalitisBunyaviruses

NIPAH virusToscana virus

Lab investigations

CSF examination : To be done in all cases Same as meninigtis of viral origin Absent CSF pleocytosis –

immunocompromised,glucocorticoid,malignancies >5 cells/ul -90 % cases >500 cells/ul – 10 % cases >1000 cells /ul –mumps ,LCMV.

ATYPICAL LYMPHOCYTES – EBV,CMV,HSV

Mollaret cells –WNV

Neutrophils -40% WNV,echovirus

>20% RBC – HSV hemorrhagic encephalitis

Decreased CSF glucose – MUMPS,LCMV

CSF PCR –Primary test for CMV,HSV,VZV,EBVSensitive and specific for HSVPostivity increases with duration of illnessNot affected by less than 1 week of therapyNext specific for enterovirusesNot established for EBVLess specific than Ab IgM --WNV

MRI Increased signal intensity in

frontotemporal,cingulate,linuglar regions on t2 weighted images

10 % may have normal MRI

EEG – periodic complexes sharp and slow at regular intervals of 2-3 sec.

Biopsy not reponding to treatment

DIFFERENTIAL DIAGNOSIS

AMOEBIC ENCEPHALITIS***:Naegleria fowleri – 1 amoebic meningoencephalitisIn immuno competenth/o swimming in potentially infected ponds.CSF nuetrophilic pleocytosisHypoglycorrhachiaMotile trophozoites –wet mount of warm fresh

CSF.Mortality is 100% Acanthoemba--- chronic granulomatous illness

HSV encephalitis

Olfactory ,gustatory hallucinationsAnosmiaUnusual or bizzare behaviourDifferentiation is important as specific treatment

avialable.Temporal lobe intensity

rabies

Encephalitis rabies (furious rabies) :Fever,fluctuating consciounessAutonomic hyperactivityHydorphobiaAerophobiaParalytic dumb rabies Acute ascending paralysisPhobic spasms not seen in due to rabies from bat

exposure…

Treatment

ICU CAREICP monitoringFluid restrictionAvoid hypotonic fluidsAnticonvulsantsPrevent apsirationPhysiotherapyDVT prophylaxis

treatment

Acyclovir start empirically10 mg/kg IV every 8 hrs for 14 days30 mg/kg/dayAdditional 7 days in case of positive CSF PCR at

14 days.Ganciclovir 5m g/kg bidfoscarnet -CMV virus 60 mg/kg every 8 hrsCidofovir – nucleotide analogue

THANK YOU

Sagittarian