1. Infections of the Central Nervous System Zheng dongming

2. Pathogen all kinds of pathogens,such as virus,bacteria,Rickettsia,Spirochaet a,parasite,prion protein,etc.

3. Category Encephalitis:brain parenchyma Meningitis:meninges Meningoencephalitis Hematogenous disemination Neuronal spread of the virus Direct infection

4. Herpes simplex virus encephalitis HSE The most common type viral encephalitis.

5. Etiology and Pathogenisis HSV-I:90%(70%) trigeminal ganglia HSV (DNA) HSV-II:neunatal

6. Pathology An acute necrotic,asymmetric hemorrhagic process with lymphotic and plasma cell reaction. Usually involves the medial temporal and inferior frontal lobe.

9. 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

10. 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.

11. Laboratory findings EEG:slow-wave, from one or two temporal or frontal lobes. CSF: Biopsy Pressure:normal or increased cell:lymphocyte and monocyte increased,RBC. protein:increased mild glucose and CL - :normal pathogen:antigen,antibody,DNA.

12. 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.

13. Differential Diagnosis Varicella-zoster encephalitis cytomegalovirus encephalitis gastrointestinal viral encephalitis ADEM

14. Treatment Antiviral therapy :Acyclovir 15~30mg/kg.d 14~21 days Ganciclovir immune therapy symptomatic therapy High fever seizure high intracranial pressure infections