Infections of the Central Nervous System

Zheng dongming

Pathogen

all kinds of pathogens,such as virus,bacteria,Rickettsia,Spirochaeta,parasite,prion protein,etc.

Category

• Encephalitis:brain parenchyma

• Meningitis:meninges

• Meningoencephalitis

• Hematogenous disemination

• Neuronal spread of the virus

• Direct infection

Herpes simplex virus encephalitisHSE

• The most common type viral encephalitis.

Etiology and Pathogenisis

•

• HSV-I:90%(70%)

• trigeminal ganglia• HSV• (DNA)• HSV-II:neunatal

Pathology

• An acute necrotic ,asymmetric hemorrhagic process with lymphotic and plasma cell reaction.

• Usually involves the medial temporal and inferior frontal lobe.

•

Clinical manifestaion• Prodromal infection:fever,headache,muscle pain,diarrhea.• Acute onset.last for several days ~1 or 2 months

• unacceptably high mortality (20–30% with acyclovir)

1 focal or generalized seizure

2 behavioral disorders;cognitive function impaired ,memory loss

3 hemiparesis,aphasia,ataxia,ophthalmoplegia, stiff neck,etc.

4disorder of consciousness.somnolent coma

5 intracranial pressure death

Laboratory findings• CT,MRI:

MRI:the most sensitive method of detecting early lesions focal oedema in the medial region of the temporal and orbital surface of the frontal lobes. Meningeal and gyral enhancement , CT usually shows reduced attenuation in one or both frontal or temporal lobes and sometimes small haemorrhages and with midline shift.

Laboratory findings

• EEG:slow-wave, from one or two temporal or frontal lobes.

• CSF:

• Biopsy

Pressure:normal or increasedcell:lymphocyte and monocyte increased ,RBC.protein:increased mildglucose and CL-:normalpathogen:antigen,antibody,DNA.

Diagnosis

• The diagnosis of HSE is usually established from the combination of the clinical and investigative features.

• definitive diagnosis:find hsv in brain or CSF by all methods .

Differential Diagnosis

• Varicella-zoster encephalitis• cytomegalovirus encephalitis• gastrointestinal viral encephalitis• ADEM

Treatment

• Antiviral therapy :Acyclovir 15~30mg/kg.d 14~21 days Ganciclovir

• immune therapy• symptomatic therapy

High fever

seizure

high intracranial pressure

infections