中樞神經系統感染(2)課件

1、中樞神經系統感染(2)1 VIRAL MENINGITIS 軸突傳播軸突傳播：neuronal spread of the virus by axonal transport (eg, herpes simplex, rabies狂犬病病毒狂犬病病毒); 1. 自身免疫性感染后脫髓鞘自身免疫性感染后脫髓鞘：autoimmune postinfections demyelination脫髓鞘脫髓鞘 (eg, varicella水痘病毒水痘病毒, influenza). 中樞神經系統感染(2)7 Pathologic changes in viral meningitis consist of a

2、n inflammatory meningeal reaction mediated by lymphocytes. 病毒性腦膜炎的病理改變是由淋巴細胞介導的病毒性腦膜炎的病理改變是由淋巴細胞介導的 炎性腦膜反應。炎性腦膜反應。 中樞神經系統感染(2)8 Encephalitis is characterized by perivascular cuffing, lymphocytic infiltration, and microglial proliferation mainly involving subcortical gray matter regions. Internuclear

3、 or intracytoplasmic inclusions are often seen. 病毒性腦炎的病理改變特點是血管周圍套袖樣病毒性腦炎的病理改變特點是血管周圍套袖樣 改變、淋巴細胞浸潤，以及累及皮層下灰質的改變、淋巴細胞浸潤，以及累及皮層下灰質的 小膠質增生，并經常可見到核漿或細胞漿內包小膠質增生，并經?？梢姷胶藵{或細胞漿內包 涵體。涵體。 中樞神經系統感染(2)9 Clinical findings- symptoms and signs Clinical manifestations include fever, headache, neck stiffness, photop

4、hobia畏光畏光, pain with eye movement, and mild impairment of consciousness. Patients usually do not appear as ill as those with bacterial meningitis. Systemic viral infection may cause skin rash, pharyngitis咽炎咽炎, lymphadenopathy淋巴結病淋巴結病, pleuritis胸胸 膜炎膜炎, carditis心肌炎心肌炎, jaundice黃疸黃疸, organomegaly器官腫大器

5、官腫大, diarrhea腹瀉腹瀉, or orchitis睪丸炎睪丸炎, and these findings may suggest a particular etiologic agent病原體病原體. 中樞神經系統感染(2)10 Because viral encephalitis involves the brain directly, marked alterations of consciousness, seizures, and focal neurologic signs can occur. When signs of meningeal irritation 腦膜刺激征

6、腦膜刺激征and brain dysfunction coexist共存共存, the condition is termed meningoencephalitis腦膜腦炎腦膜腦炎. 中樞神經系統感染(2)11 中樞神經系統感染(2)12 Laboratory findings CSF analysis is the most important laboratory test. CSF pressure is normal or increased a lymphocytic or monocytic pleocytosis腦脊液細胞數增多腦脊液細胞數增多 is present, with

7、 cell counts usually less than 1000/ml. (higher counts can be seen in lymphocytic choriomeningitis脈絡叢腦膜炎脈絡叢腦膜炎 or herpes simplex encephalitis.) A polymorphonuclear多形核白細胞多形核白細胞 pleocytosis can occur early in viral meningitis, while red blood cells may be seen with herpes simplex encephalitis. 中樞神經系統感

8、染(2)13 Protein is normal or slightly increased (usually 80120mg/dL). Glucose is usually normal, but may be decreased in mumps腮腺炎腮腺炎, herpes zoster 帶狀皰疹帶狀皰疹, or herpes simplex encephalitis. Grams stain and bacterial, fungal, and acid-fast bacillius(AFB) cultures are negative. Oligoclonal bands寡克隆區(qū)帶寡克

9、隆區(qū)帶and CSF protein electrophoresis電泳電泳abnormalities may be present. An etiologic diagnosis can often be made by virus isolation, polymerase chain reaction, or acute- and convalescent phase恢復期恢復期CSF antibody titers抗體滴度抗體滴度. 中樞神經系統感染(2)14 Blood counts may show a normal white cell count, leukopenia白血球減

10、少白血球減少 癥癥, or mild leukocytosis白細胞增多白細胞增多. Serum amylase血清淀粉酶血清淀粉酶is frequently elevated in mumps 腮腺炎腮腺炎; abnormal liver function tests are associated with both hepatitis viruses肝炎病毒肝炎病毒and infectious mononucleosis單核細胞增多癥單核細胞增多癥. 中樞神經系統感染(2)15 The EEG is diffusely slow, especially if there is direct

11、 cerebral involvement. 中樞神經系統感染(2)16 Diagnosis 中樞神經系統感染(2)17 Differential diagnosis The differential diagnosis of meningitis with mononuclear cell pleocytosis includes partially treated bacterial meningitis治療不徹底治療不徹底 的細菌性腦膜的細菌性腦膜炎 as well as syphilitic梅毒梅毒 的, tuberculous結核性結核性的, fungal, parasitic寄生物

12、寄生物的, neoplastic腫瘤腫瘤的, and other meningitides腦腦(脊脊)膜膜炎. 中樞神經系統感染(2)18 Evidence of systemic viral infection and CSF wet mounts, stained smears, cultures, and cytologic examination細胞學檢查細胞學檢查can distinguish among these possibilities. When presumed early viral meningitis is associated with a polymorphon

13、uclear多形核白細胞多形核白細胞 pleocytosis of less than 1000 white blood cells/mL and normal CSF glucose, one of two strategies can be used. 中樞神經系統感染(2)19 The paitent can be treated for bacterial meningitis until the results of CSF cultures are known; Treatment can be withheld and lumbar puncture腰椎穿刺術腰椎穿刺術 repe

14、ated in 612 hours. If the meningitis is viral in origin, the second sample should show a mononuclear cell pleocytosis. 中樞神經系統感染(2)20 A disorder that may be clinically indistinguishable from viral encephalitis is the immune- mediated encephalomyelitis that may follow viral infections such as influenz

15、a, measles麻疹麻疹, or chickenpox水痘水痘. Progressive neurologic disfunction typically begins a few days after the viral illness, but can also occur either simultaneously同時發(fā)生同時發(fā)生 or up to several weeks later. 中樞神經系統感染(2)21 Neurologic abnormalities result from perivenous 靜脈周圍的靜脈周圍的 demyelination脫髓鞘脫髓鞘, with

16、 often severely affects the brainstem. The CSF shows a lymphocytic pleocytosis腦脊液細胞數增多腦脊液細胞數增多, usually with cell counts of 50150/mL, and mild protein elevation. 中樞神經系統感染(2)22 Treatment Except for herpes simplex encephalitis, which is discussed separately no specific therapy for viral meningitis and

17、 encephalitis is available. Corticosteroids are of no proven benefit except in immune- mediated postinfectious syndromes. 中樞神經系統感染(2)23 Headache and fever can be treated with acetaminophen醋氨酚醋氨酚, but aspirin should be avoided, especially in children and young adults, because of its association with

18、Reyes syndrome. Seizures usually respond to phenytoin 苯妥英鈉苯妥英鈉or phenobarbital苯苯 巴比妥巴比妥. Supportive measures in comatose昏昏 睡的睡的patients include mechanical ventilation and intravenous or nasogastric feeding鼻飼鼻飼. 中樞神經系統感染(2)24 Prognosis Symptoms of viral meningitis usually resolve spontaneously within

19、 2 weeks regardless of the causative agent, although residual deficits后遺癥后遺癥may be seen. The outcome of viral encephalitis varies with the specific virus -for example, herpes simplex virus infections are associated with severe morbidity and high mortality rates. Mortality rates as high as 20% have a

20、lso been reported in immune- mediated encephalomyelitis腦脊髓炎腦脊髓炎 following measles麻疹麻疹 infections. 中樞神經系統感染(2)25 Herpes simplex virus (HSV) encephalitis 中樞神經系統感染(2)26 HSV is the most common cause of sporadic散發(fā)的散發(fā)的 fatal encephalitis in the United States. About two-thirds of cases patients over 40 yea

21、rs of age. Primary herpes infections most often present as stomatitis口炎口炎 ( HSV type 1) or a venereally 性交性交 的的transmitted genital生殖器生殖器eruption 出疹出疹 (HSV tpye 2). 中樞神經系統感染(2)27 The virus migrates along nerve axons軸突軸突to sensory ganglia神經節(jié)神經節(jié), where it persists in a latent form and may be subsequent

22、ly reactivated. It is not clear whether HSV type 1 encephalitis, the most common type in adults, represents a primary infection or a reactivation of latent infection. 中樞神經系統感染(2)28 Neonatal新生兒的新生兒的HSV encephaltis usually results from acquisition獲得獲得 of type 2 virus during passage through the brith c

23、anal of a mother with active genital生殖器的生殖器的 lesions. Central nervous system involvement by HSV type 2 in adults usually causes meningitis, rather than encephalitis. 中樞神經系統感染(2)29 Pathology HSV tpye 1 encephalitis is an acute, necrotizing引壞死的引壞死的, asymmetric不對稱的不對稱的hemorrhagic出血性出血性 的的process with l

24、ymphocytic and plasma cell漿細胞漿細胞reaction. Usually involves the medial temporal and inferior frontal lobes. Intranuclear inclusions核內包涵體核內包涵體may be seen in neurons神經元神經元and glia神經神經 膠質膠質. Patients who recover康復期康復期 may show cystic囊的囊的necrosis壞死壞死of the involved regions. 中樞神經系統感染(2)30 中樞神經系統感染(2)31 中樞

25、神經系統感染(2)32 中樞神經系統感染(2)33 嗜酸性嗜酸性Cowdry A型包涵體型包涵體 中樞神經系統感染(2)34 Clinical Finding- A Symptoms and Signs The clinical syndrome may include headache, stiff neck, vomiting, behavioral disorders, memory loss, anosmia嗅覺喪失嗅覺喪失, aphasia, hemiparesis輕偏癱輕偏癱, and focal or generalized seizures. 中樞神經系統感染(2)35 Act

26、ive herpes labialis唇皰疹唇皰疹is seen occasionally, but does not reliably implicate HSV as the cause of encephalitis. 中樞神經系統感染(2)36 HSV encephalitis is uaually rapidly progressive over several days and may result in coma or death. The most common sequelae 后遺癥后遺癥 in patients who survive are memory and beh

27、avior disturbances, reflecting the predilection 嗜好嗜好, 偏愛偏愛of HSV for limbic structures. 中樞神經系統感染(2)37 Laboratory Findings 中樞神經系統感染(2)38 Laboratory Findings-CSF The CSF in HSV tpye 1 encephalitis most often shows increased pressure lymphocytic or mixed lymphocytic and polymorphonuclear多形核白細胞多形核白細胞 pl

28、eocytosis( 50100 white blood cells/mL) mild protein elevation, and normal glucose. Red blood cells, xanthochromia 黃變黃變, and decreased glucose are seen in some cases. 中樞神經系統感染(2)39 Laboratory Findings- VIRUS The virus generally cannot be isolated from the CSF, but viral DNA has been detected by the p

29、olymerase chain reaction聚合酶鏈反應聚合酶鏈反應 in some cases. 中樞神經系統感染(2)40 HSV抗體檢定 ELASA是現今國際上通用的HSV抗體檢測方 法。 本方法采用雙份血清和雙份腦脊液作HSV-1 抗體的動態(tài)檢測。 診斷標準： 雙份CSF抗體有增高趨勢，滴度1:8以上； 雙份CSF抗體4倍以上升高； 血與CSF的抗體比值40。 中樞神經系統感染(2)41 Laboratory Findings-EEG The EEG may show periodic周期的周期的 slow-wave complexes arising from one or bo

30、th temporal lobes 中樞神經系統感染(2)42 Laboratory Findings- CT MRI CT scans and MRI may show abnormalities in one or both temporal lobes. These can extend to frontal or parietal regions頂區(qū)頂區(qū) and are sometimes enhanced with the infusion注入注入of contrast material 造影劑造影劑. However, imaging studies may also be nor

31、mal. 中樞神經系統感染(2)43 中樞神經系統感染(2)44 中樞神經系統感染(2)45 中樞神經系統感染(2)46 中樞神經系統感染(2)47 Diagnosis 中樞神經系統感染(2)48 中樞神經系統感染(2)49 中樞神經系統感染(2)50 中樞神經系統感染(2)51 Differential Diagnosis The symptoms and signs are not specific for herpes virus infection. The greatest diagnostic difficulty is distinguishing between HSV enc

32、ephalitis and brain abscess腦膿腫腦膿腫, and the tow disorders often cannot be differentiated on clinical grounds alone. 中樞神經系統感染(2)52 brain abscess 中樞神經系統感染(2)53 brain abscess 中樞神經系統感染(2)54 Other CNS infections and vasculitis血管炎血管炎 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 EEG, CT, or MRI findings. Ho