中枢神经系统感染1精选课件

1、中枢神经系统感染1精选中枢神经系统感染1精选中枢神经系统感染1精选中枢神经系统感染1精选Viral meningitis refers to meningitis caused by a viral infection. Children and young adults are frequently affected. Viral meningitis is most often caused by enteric 肠道的viruses Viral encephalitis by childhood exanthems皮疹, arthropod-borne节肢动物agents虫媒性病原体,

2、and herpes simplex type 1.Viral meningitis refers to menCause最常见柯萨奇病毒ECHO病毒肠道病毒其次流行性腮腺炎单纯疱疹病毒腺病毒Cause最常见其次PathologyViral infections can affect the central nervous system in three ways血源性播散 ：hematogenous dissemination of a systemic viral infection(eg, arthropod-borne viruses虫媒性病毒); 轴突传播：neuronal spre

3、ad of the virus by axonal transport (eg, herpes simplex, rabies狂犬病病毒); 自身免疫性感染后脱髓鞘：autoimmune postinfections demyelination脱髓鞘 (eg, varicella水痘病毒, influenza). PathologyViral infections can Pathologic changes in viral meningitis consist of an inflammatory meningeal reaction mediated by lymphocytes.病毒性

4、脑膜炎的病理改变是由淋巴细胞介导的炎性脑膜反应。Pathologic changes in viral meEncephalitis is characterized by perivascular cuffing, lymphocytic infiltration, and microglial proliferation mainly involving subcortical gray matter regions. Internuclear or intracytoplasmic inclusions are often seen. 病毒性脑炎的病理改变特点是血管周围套袖样改变、淋巴细

5、胞浸润，以及累及皮层下灰质的小胶质增生，并经常可见到核浆或细胞浆内包涵体。Encephalitis is characterized Clinical findings-symptoms and signsClinical manifestations include fever, headache, neck stiffness, photophobia畏光, pain with eye movement, and mild impairment of consciousness.Patients usually do not appear as ill as those with bact

6、erial meningitis. Systemic viral infection may cause skin rash, pharyngitis咽炎, lymphadenopathy淋巴结病, pleuritis胸膜炎, carditis心肌炎, jaundice黄疸, organomegaly器官肿大, diarrhea腹泻, or orchitis睾丸炎, and these findings may suggest a particular etiologic agent病原体. Clinical findings-symptoms aBecause viral encephali

7、tis involves the brain directly, marked alterations of consciousness, seizures, and focal neurologic signs can occur. When signs of meningeal irritation脑膜刺激征and brain dysfunction coexist共存, the condition is termed meningoencephalitis脑膜脑炎. Because viral encephalitis inv中枢神经系统感染1精选Laboratory findingsC

8、SF analysis is the most important laboratory test. CSF pressure is normal or increaseda lymphocytic or monocytic pleocytosis脑脊液细胞数增多 is present, with cell counts usually less than 1000/ml. (higher counts can be seen in lymphocytic choriomeningitis脉络丛脑膜炎or herpes simplex encephalitis.) A polymorphonu

9、clear多形核白细胞 pleocytosis can occur early in viral meningitis, while red blood cells may be seen with herpes simplex encephalitis. Laboratory findingsProtein is normal or slightly increased (usually 80120mg/dL). Glucose is usually normal, but may be decreased in mumps腮腺炎, herpes zoster带状疱疹, or herpes

10、simplex encephalitis.Grams stain and bacterial, fungal, and acid-fast bacillius(AFB) cultures are negative. Oligoclonal bands寡克隆区带and CSF protein electrophoresis电泳abnormalities may be present. An etiologic diagnosis can often be made by virus isolation, polymerase chain reaction, or acute- and conva

11、lescent phase恢复期CSF antibody titers抗体滴度.Protein is normal or slightly Blood counts may show a normal white cell count, leukopenia白血球减少症, or mild leukocytosis白细胞增多. Serum amylase血清淀粉酶is frequently elevated in mumps 腮腺炎; abnormal liver function tests are associated with both hepatitis viruses肝炎病毒and i

12、nfectious mononucleosis单核细胞增多症. Blood counts may show a normalThe EEG is diffusely slow, especially if there is direct cerebral involvement.The EEG is diffusely slow, espDiagnosisDiagnosisDifferential diagnosisThe differential diagnosis of meningitis with mononuclear cell pleocytosis includes partia

13、lly treated bacterial meningitis治疗不彻底的细菌性脑膜炎 as well as syphilitic梅毒的, tuberculous结核性的, fungal, parasitic寄生物的, neoplastic肿瘤的, and other meningitides脑(脊)膜炎. Differential diagnosisEvidence of systemic viral infection and CSF wet mounts, stained smears, cultures, and cytologic examination细胞学检查can disti

14、nguish among these possibilities.When presumed early viral meningitis is associated with a polymorphonuclear多形核白细胞pleocytosis of less than 1000 white blood cells/mL and normal CSF glucose, one of two strategies can be used. Evidence of systemic viral infThe paitent can be treated for bacterial menin

15、gitis until the results of CSF cultures are known;Treatment can be withheld and lumbar puncture腰椎穿刺术 repeated in 612 hours. If the meningitis is viral in origin, the second sample should show a mononuclear cell pleocytosis.The paitent can be treated forA disorder that may be clinically indistinguish

16、able from viral encephalitis is the immune-mediated encephalomyelitis that may follow viral infections such as influenza, measles麻疹, or chickenpox水痘. Progressive neurologic disfunction typically begins a few days after the viral illness, but can also occur either simultaneously同时发生 or up to several

17、weeks later. A disorder that may be clinicaNeurologic abnormalities result from perivenous 静脉周围的demyelination脱髓鞘, with often severely affects the brainstem. The CSF shows a lymphocytic pleocytosis脑脊液细胞数增多, usually with cell counts of 50150/mL, and mild protein elevation.Neurologic abnormalities resu

18、lTreatmentExcept for herpes simplex encephalitis, which is discussed separately no specific therapy for viral meningitis and encephalitis is available.Corticosteroids are of no proven benefit except in immune-mediated postinfectious syndromes. TreatmentExcept for herpes simHeadache and fever can be

19、treated with acetaminophen醋氨酚, but aspirin should be avoided, especially in children and young adults, because of its association with Reyes syndrome. Seizures usually respond to phenytoin 苯妥英钠or phenobarbital苯巴比妥. Supportive measures in comatose昏睡的patients include mechanical ventilation and intrave

20、nous or nasogastric feeding鼻饲.Headache and fever can be treaPrognosisSymptoms of viral meningitis usually resolve spontaneously within 2 weeks regardless of the causative agent, although residual deficits后遗症may be seen. The outcome of viral encephalitis varies with the specific virus -for example, h

21、erpes simplex virus infections are associated with severe morbidity and high mortality rates. Mortality rates as high as 20% have also been reported in immune-mediated encephalomyelitis脑脊髓炎following measles麻疹 infections. PrognosisSymptoms of viral menHerpes simplex virus (HSV) encephalitisHerpes sim

22、plex virus (HSV) encHSV is the most common cause of sporadic散发的 fatal encephalitis in the United States. About two-thirds of cases patients over 40 years of age.Primary herpes infections most often present as stomatitis口炎( HSV type 1) or a venereally 性交的transmitted genital生殖器eruption出疹 (HSV tpye 2).

23、 HSV is the most common cause oThe virus migrates along nerve axons轴突to sensory ganglia神经节, where it persists in a latent form and may be subsequently reactivated.It is not clear whether HSV type 1 encephalitis, the most common type in adults, represents a primary infection or a reactivation of late

24、nt infection. The virus migrates along nerveNeonatal新生儿的HSV encephaltis usually results from acquisition获得of type 2 virus during passage through the brith canal of a mother with active genital生殖器的lesions. Central nervous system involvement by HSV type 2 in adults usually causes meningitis, rather th

25、an encephalitis.Neonatal新生儿的HSV encephaltis usPathologyHSV tpye 1 encephalitis is an acute, necrotizing引坏死的, asymmetric不对称的hemorrhagic出血性的process with lymphocytic and plasma cell浆细胞reaction. Usually involves the medial temporal and inferior frontal lobes. Intranuclear inclusions核内包涵体may be seen in n

26、eurons神经元and glia神经胶质. Patients who recover康复期 may show cystic囊的necrosis坏死of the involved regions.PathologyHSV tpye 1 encephalit中枢神经系统感染1精选中枢神经系统感染1精选中枢神经系统感染1精选嗜酸性Cowdry A型包涵体嗜酸性Cowdry A型包涵体Clinical Finding- A Symptoms and SignsThe clinical syndrome may include headache, stiff neck, vomiting, behav

27、ioral disorders, memory loss, anosmia嗅觉丧失, aphasia, hemiparesis轻偏瘫, and focal or generalized seizures. Clinical Finding- A SymptomsActive herpes labialis唇疱疹is seen occasionally, but does not reliably implicate HSV as the cause of encephalitis.Active herpes labialis唇疱疹is seHSV encephalitis is uaually

28、 rapidly progressive over several days and may result in coma or death. The most common sequelae 后遗症 in patients who survive are memory and behavior disturbances, reflecting the predilection 嗜好, 偏爱of HSV for limbic structures. HSV encephalitis is uaually raLaboratory FindingsLaboratory FindingsLabor

29、atory Findings-CSFThe CSF in HSV tpye 1 encephalitis most often shows increased pressurelymphocytic or mixed lymphocytic and polymorphonuclear多形核白细胞 pleocytosis( 50100 white blood cells/mL) mild protein elevation, and normal glucose.Red blood cells, xanthochromia 黄变, and decreased glucose are seen i

30、n some cases. Laboratory Findings-CSFThe CLaboratory Findings-VIRUSThe virus generally cannot be isolated from the CSF, but viral DNA has been detected by the polymerase chain reaction聚合酶链反应in some cases. Laboratory Findings-VIRUSTheHSV抗体检定ELASA是现今国际上通用的HSV抗体检测方法。本方法采用双份血清和双份脑脊液作HSV-1抗体的动态检测。诊断标准： 双

31、份CSF抗体有增高趋势，滴度1:8以上； 双份CSF抗体4倍以上升高； 血与CSF的抗体比值40。HSV抗体检定ELASA是现今国际上通用的HSV抗体检测方法Laboratory Findings-EEGThe EEG may show periodic周期的slow-wave complexes arising from one or both temporal lobesLaboratory Findings-EEGThe ELaboratory Findings- CT MRICT scans and MRI may show abnormalities in one or both t

32、emporal lobes. These can extend to frontal or parietal regions顶区and are sometimes enhanced with the infusion注入of contrast material造影剂. However, imaging studies may also be normal.Laboratory Findings- CT MRIC中枢神经系统感染1精选中枢神经系统感染1精选中枢神经系统感染1精选中枢神经系统感染1精选DiagnosisDiagnosis中枢神经系统感染1精选中枢神经系统感染1精选中枢神经系统感染1

33、精选Differential DiagnosisThe symptoms and signs are not specific for herpes virus infection. The greatest diagnostic difficulty is distinguishing between HSV encephalitis and brain abscess脑脓肿, and the tow disorders often cannot be differentiated on clinical grounds alone.Differential DiagnosisThe sympbrain abscessbrain abscessbrain abscessbrain abscessOther CNS infections and vasculitis血管炎can also mimic HSV encephalitis. Deginitive diagnosis can be made by biopsy of affected brain areas, with the choice of biopsy site guided by the