流行性乙型脑炎的教育课件

1、流行性乙型脑炎的教育课件Case reportHistory taking：A boy,4 years old，born in the countryside.Fever last for 4 days，convulsion and confusion last about 6 hours.Physical examination：T 40.5，R 30bpm，P 120bpm，BP100/60mmHg. Unconsciousness, conjunctival edema, lungs can be heard wheezes. Muscle hypertonia, knee hyperr

2、eflexia, Babinski sign(+)Other history?Accessory examination?AbstractJapanese encephalitis(JE), an acute infectious disease caused by the mosquito-borne Japanese encephalitis virus(JEV) and featured as inflammation in brain parenchyma.Fever, confusion, coma, convulsion,pathological reflex and mening

3、eal irritation . Respiratory failure in severe cases,high mortality,and10% result in permanent neuropsychiatric sequelea.EtiologyA single stranded RNA, 40-50nm,11 kilobases genomes.RNA genome is packaged in the capsid protein forming the core of the virus.The genomes also encodes several nonstructur

4、al proteins (NS1,NS2a,NS3,NS4a,NS4b,and NS5)JEV can be killed by disinfectant,100 2 minutes or 56 30 minutesEtiologyAntigenic stability, infection can produce complement-binding antibodies, neutralizing antibodies and hemagglutination inhibition antibodies, contribute to clinical diagnosis and epide

5、miological investigationEpidemiologySources of infection: JE is a zoonosis, mosquitoes become infected by feeding domestic pigs and wild birds infected with the JEV. JEV is amplified in the blood systems of the domestic pigs and wild birds. Pigs are the improtant amplified and reservoirs.Other reser

6、vior includes cow, sheep, horse,duck,goose and chicken.EpidemiologyRoute of transmission: the bite of an infected mosquito, primarily Culex species. Humans are a dead-end host in the JEV tramsmission cycle. JEV is not transmitted from person-to-person. Only domestic pigs and wild birds are carriers

7、of the JEV.Epidemiology.Susceptible population: Generally susceptible, especially residents of rural areas in endemic location, mostly asymptomatic. The ratio of patients and latent infection was 1 :1000-2000 . Pre-existing antibodies. Countries that still have periodic epidemics include India ,Camb

8、odia ,Nepal and so on.Epidemiology.Epidemic feature: most cases in temperate and subtropical areas occur from June to September, while in tropical areas occur throughout the year.Five genotypes : genotypes I ,II ,III, IV,V. Genotypes I and III occur principally in temperate, epidemic areas,and genot

9、ype II and IV occur principally in tropical ,endemic regions.Pathogenesis and PathologyJEVMononuclear macrophages multiplyviremiaInvade the CNSNot invade the CNSIncidenceLatent infectionThis section of brain was taken from a patient with Japanese encephalitis, and shows the gross pathology found in

10、all of the arbovirus encephalitides. The changes, which consist of perivascular congestion and hemorrhage, may be diffuse or focal, but they are seen predominantly in cortical gray and deep gray matterPathogenesis and PathologyJEVDirect invasionAntigen-antibody binding to the immune attackNerve cell

11、 lesionsVascular sheath formationThalamus, basal ganglia, brain stem, cerebellum,hippocampus, cerebral cortexGlialcell proliferationShow softening lesions, oval-shaped light pale area, the structure was loose meshClinical manifestationsIncubation period of 5-15 days.the vast majority of infections a

12、re asymptomatic,only 1 in 250 infections develop into encephalitis.Typical manifestation:there are four stagesThe primary stage (1-3 days): onset was sudden with high fever, up to 39-41 in 1-2 days accompanied headache and malaise. Anorexia, nausea,or abdominal pain. Apathy and neck rigidity.Clinica

13、l manifestationsThe proximity stage (fourth to tenth days)HyperthermiaConscious disturbanceConvulsionRespiratory failureOther nervous symptoms and signsCirculation failureClinical manifestationsThe proximity stage：Hyperthermia: acute onset; more than 40, lasts 7-10 days generally and some grave case

14、s can last for 3 weeks. The higher temperature, the longer course, the more serious of JE.Clinical manifestationsThe proximity stageConscious disturbance：Lethargy, delirium, coma, and disorientation are main presentationsAppears mostly at the 3-8 days,lasting for almost 1 weekA positive corralation

15、between the serious and the lasting time of coma and the gravity of JE and prognosisClinical manifestationsThe proximity stage Convulsion：Causes: high fever, cerebral edema, brain parenchymal inflammationOne or more focal/asymmetric signs appearing in the first few daysLight : the face, lips, local

16、convulsions, severe cases of the bodyAbout 30% of survivors have frank persistent motor language impairment.Clinical manifestationsRespiratory failure: caused by inflammatory of brain parenchyma, hypoxia, cerebral edema, acute intracranial hypertension and cerebral hernia Cerebral henia：Spitting vom

17、iting, convulsionsComa increasedPupil changes. Anterior fontanel bulging, papilledemaClinical manifestationsThe proximity stage：Circulation failure: rarely, tachycardia, hyper or hypotension and rarely ECG evidence of pericarditis.Other nervous symptoms and signs: superficial reflex disappears or we

18、akens; deep reflex accentuations first and the disappears and there are symptoms and meningeal irritation.Clinical manifestations hyperthermiaconvulsionRespiratory failureAre critical presentations of JE and respiratory failure is the leading cause of deathClinical manifestationsThe convalescence st

19、age：Defervescence of fever and neurologic improvementIt usually lasts for at least two weeksClinical manifestationsThe sequelae stage：the existence of neuropsychiatric symptoms after 6 months 。 The incidence of about 5% to 20%. Axial T2 weighted (TR/TE=2500/90) image. (A) Hyperintense lesions at bil

20、ateral thalami (arrows) were shown on the 14th days after onset. (B) Small hyperintense lesions at bilateral thalami (arrows) on the 60th day after onsetClinical manifestationsLaboratory examinationsWhite blood cell: grows up to 1020109/L,neutrophil occupied more than 80%. Some patients have normal

21、WBC counts.Cerebrospinal fluid (CSF)：lumbar puncture to obtain CSF samples. Laboratory examinationsCerebrospinal fluid (CSF)：The opening pressure is usually normal but may be raised. Mononuclear white blood cells may be 50500106/L; Glucose levels are normal; Protein levels are mildly elevated in mos

22、t cases,often less than 900mg/dlLaboratory examinationsAntiboby detection: Specific IgM antibodies is the standard diagnostic test for JE, nearly 100% sensitivity; IgM antibody levels may be found even within 7 days of symptoms. False-negative results may occur if the samples are testd too early. So

23、me cross-reactivity may arise from other flaviviruses and from JE and yellow fever vaccinations Laboratory examinationsNucleic acid detection: detection of viral genome by RT-PCR is easier to perform and highly reliable with 100% sensitivity , JEV has been isolated up to even almost 4 months after c

24、linical symptoms have begunInmaging studies: MRI and CTDiagnosisEpidemiology data: rigorous seasonality :summer and autumn; less than 10 years old are more susceptible but more adult patients are seen now Clinical features：acute onset headache, vomitting, hyperthermia, convulsion and positive pathol

25、ogic reflex and meningeal irritation signDiagnosisLaboratory examinations：peripheral blood picture , CSF, serum antibodies,EEG,CT and MRI, brain biopsy Virological investigation: JEV is difficult to be separated from blood and CSF. JEV antigen can be detected in such body fluid using PCR.Differentia

26、l diagnosisToxic bacillary dysenteryTuberculous meningitisPurulent meningitisEncephalitis bOnsetAcute，24 hour peakChronic,long course1-2 peak1-2 peakSeasonSummer to autumnNon-seasonalwinter and springSummer to autumnCSFNormalChloride and glucose are low, high protein, cell count 50*106/LChloride and

27、 glucose are low, high protein, cell count 1000*106/LChloride and glucose are normal, high protein, cell count 50500*106/LPathogenAnus dry smear of pus cells, blood cultures of ShigellaCSF film smear TBCSF smear staining bacteriaCSF bacterial testing was negative. Specific IgM antibodiesTreatmentGen

28、eral treatmentSymptomatic treatment hyperthermia, convulsion , respiratory failure TreatmentGeneral treatmentComa patients should pay attention ：Oral cleaningPrevent secondary bacterial infectionPrevent bed sores occurProtect the corneaAnti-falling bedprevent the tongue bittenNote that water, electr

29、olytes, acid-base balance, but not too much infusion volume to prevent brain edemaTreatmenthyperthermia：Lower the room temperaturePhysical cooling:ice or alcohol cool salineWith convulsions: hibernation therapy (chlorpromazine + promethazine)Treatmentconvulsion：Cerebral edema: dehydration, 20% manni

30、tol 1-2g / Kg, intravenous infusion, 4-6h time, while combined with adrenal cortex hormones, furosemide, 50% GS, to reduce vascular permeability, Prevention of brain edema and dehydration agent rebound applicationRespiratory blockage: suction, oxygen, if necessary, tracheotomyTreatmentRespriatory fa

31、ilure：Brain edema : dehydrating agentCentral respiratory failure: available respiratory stimulantsImprove microcirculation, reduce cerebral edema: vasodilatorsTreatmentRespriatory failure：Respiratory secretions Infarct: suction, atomization inhalation of -chymotrypsin; with bronchospasm may be 0.25%

32、 -0.5% isoproterenol inhalation. And appropriate treatment with antibiotics such as bacterial infection. If necessary, endotracheal intubation or incision, artificial respiration ventilationTreatmentRecovery and sequelae of treatment: acupuncture, physical therapy, hyperbaric oxygen therapyprognosis

33、Control the source of infection : Vaccine the pigs before the epidemic seasonCut off the transmission: anti-mosquito, mosquito control.Protection of susceptible populations, vaccination injectionsprognosisVaccination injections: the current dosing schedule for patients aged 3 years or older is 1ml s

34、ubcutaneously on days 0,7,and 30 (0.5ml in patients aged 1-2y). Administer the last dose of vaccine at least 10days prior to travel in an endemic area.Adverse reactions include local pain and redness, fever, gastrointestinal symptoms, headacheCase reportHistory taking：A boy,4 years old，born in the countryside.Fever last for 4 days，convulsion and confusion last about 6 hours.Physical examination：T 40.5，R 30bpm，P 120bpm，B