Download Cholera Definition

Epidemic Encephalitis B
Dept. Of Infectious Disease
Shengjing Hospital
CMU
Definition
 Epidemic encephalitis B is acute infectious disease
caused by encephalitis B virus,usually occurs in summer
&fall.The virus is transmitted by mosquito.
 Pathologic lesions: cerebral parenchyma
 Clinical feature: high fever
altered consciousness
convulsion
meningeal irritation
respiratory failure
Etiology
 Causative agent: encephalitis B virus
genus flavivirus of flaviviridae
 single strain of positive-sense RNA,
 virion is spheric, diameter: 15 ~ 22nm,
Resistance: unstable in environment,
Sensitive to heat, disinfectants,
ultraviolet rays
Etiology
antigenicity: stable
 hemagglutination inhibiting Ab
 complement fixing Ab
 neutralizing Ab
Epidemiology
 Source of infection
domestic animals:
pig, horse, dog
poultry:
chicken, duck, goose.
patients:
Epidemiology
 Route of transmission
insect borne: mosquito biting ,
vector: mosquito, culex tritaeniorhynchus.
Survived winter mosquitoes
pigs
mosquitoes
mosquitoes
pigs
person
Epidemiology
 Susceptibility of population:
 universal susceptible
 lifelong immunity
 subclinical infection : overt infection
1000~2000:1
Epidemiology
 Epidemiologic features
 sporadic from July to Sep.
 children under 10yrs (2~6yrs)
 hypersporadic property
Pathogenesis
virus
mosquito biting
replication in mononuclear-phagocyte system (MPS)
blood stream
brief viremia
blood-brain barrier
clearance
CNS
subclinical inf.
onset of illness
No. of virus of invasion
cellular immunity
blood brain barrier
Pathology
 Place of lesion:
 all of CNS
 cerebral cortex, midbrain and thalamus .
 Pathologic features
 gross examination:
 congestion
 hemorrhage
 cerebral edema
 soften focuses
Pathology
 microscopic examination:
 vascular lesion: endothelial cells swelling,
necrosis
 neuron degeneration & necrosis
 neurogliocyte hyperplasia & inflammatory cells
infiltration,
perivascular cuffing ,
neuronophagia.
Clinical manifestation
 incubation period:10~14 days (4~21days )
 typical encephalitis B




Initial period
crisis period
convalescent period
sequela period
Clinical manifestation
 Initial period : on the 1st to 3rd days
 abrupt onset
 fever with headache , nausea, vomiting lethargy,
 abdominal pain , diarrhea,
Clinical manifestation
 Crisis period- on the 4th ~10th days
 high fever: >40℃, sustained for 7~10 days.
 altered consciousness:
lethargy, confusion, delirium, stupor, semicoma,
coma.
 convulsion or twitch:(40~60%)
 respiratory failure: 15~40%
Clinical manifestation
 central RF:
• reason of central RF:
• lesion of cerebral parenchyma (respiratory center
injury in oblongata
medulla)
• cerebral edema
• brain hernia
• intracranial hypertension
• hyponatremic encephalopathy
Clinical manifestation
• manifestation of
central RF:
• cacorhythmic breathing
(cheyne-stokes breathing, apnea)
• brain hernia
 peripheral RF:
• dyspnea, regular breathing
Clinical manifestation
 Other symptoms & signs of CNS

meningeal irritations (neck stiffness
Kernigs & Brudzinskis signs positive)

Deep tendon reflexes from hyperactive to
disappear

pathologic reflexes positive

limbs paralysis
Clinical manifestation
 Convalescent period
 T drop to normal in 2~5 days
 neurologic function regain gradually(2W)
 remain some behavioral & psychologic
abnormalities,
aphasia, dementia, rigidity paralysis.
 >6month - sequela
Clinical manifestation
 Sequela period
 aphasia
 dementia
 persistent paralysis
Clinical manifestation
 Clinical type:

mild type
 common type
 severe type
 fulminant type
Clinical manifestation
T
AC
CV
RF
DC
SQ
-
-
5~7d
-
-
mild
<39℃
lethargy
common
39~40 ℃
semicoma
±
-
10d
severe
40~41 ℃
coma
+
±
>2W
fulminant
>41℃
deep coma
+
+
death
+
+
Laboratory Findings
 Blood picture: WBC 10~20×109 /L
neutrophil >80%
 Cerebrospinal fluid - aseptic meningitis
 transparent or slightly cloudy,
 pressure may be elevated
 pleocytosis: 50~500×106/L
 protein may be elevated mildly
 glucose and chloride are normal
Laboratory Findings
 Serological test:
 specific IgM Ab: blood or CSF,
3~4d after onset, peak on 2 week
ELISA or indirect immunofluorescence
 complement fixing Ab:
2 week after onset, peak on 5~6 week,
 anamnestic diagnosis
 epidemiologic investigation
Laboratory Findings
 hemagglutination inhibition Ab:
5d after onset, peak on 2 week
 diagnosis: 4 fold increase in titer
 epidemiologic investigation
 neutralized Ab
epidemiologic investigation
Laboratory Findings
pathogenic test
virus isolation: blood, CSF, brain tissue
RT-PCR : RNA
Diagnosis
 Epidemiological data:
 7~9 month
 <10yrs
 Clinical manifestation:
fever, headache, vomiting, altered consciousness,
convulsion, meningeal irritation, pathologic
reflexes positive.
 Laboratory findings:WBC, CSF, IgM
Differential Diagnosis
 toxic bacillary dysentery
high fever,convulsion,coma.
 <24h
 circulatory failure: early
 stool examination: WBC, RBC
 CSF: normal
 meningeal irritation: negative
Differential Diagnosis
 tuberculous meningitis
CSF, meningeal irritation
 purulent meningitis
 other viral encephalitis
Treatment
 General therapy:
 Isolation:
preventing mosquito biting, T<30℃
 nursing: mouth, skin, eye,
turn over
clapping back
sputum aspiration
Treatment
 fluid & electrolyte supplementation
adult: 1500~2000ml/d
children: 50~80ml/kg/d
 Symptomatic therapy
 high fever: T<38℃
Treatment
 physical cooling
(ice bag, alcohol bathing, cold saline enema)
 drug cooling
antipyretic
subhibernation:
chlorpromazine 0.5~1mg/kg/time
phenergan 0.5~1mg/kg/time
4~6h, 3~5day
Treatment
 convulsion:
fever: cooling
brain edema: 20% mannitol 1~2g/kg/time
50% glucose
dexamethason
Treatment
sedative:
valium: adult:10~20mg/time
children: 0.1~0.3mg/ kg/ time
10% chloral hydrate:
adult:1~2g/time
children: 60~80mg/kg/time
subhibernation:
Treatment
 respiratory failure:
 keep airway clear
• sputum aspiration
• turn over , clapping back, postural drainage
• aerosolization
• inhalation of oxygen
Treatment
 reducing cerebral edema & hernia
dehydrate :
20% mannitol :1~2g/kg/time
50% glucose ,
 vasodilator:
654-2: adult: 20mg/time
children: 0.5~1mg/kg/time
10~30 min
Treatment
 respiratory stimulant:
lobeline: adult: 3~9mg/time
children: 0.15~0.2mg/kg/time
coramine: adult: 0.375~0.75g/time
children: 5~10mg/kg/time
 tracheal intubation or tracheotomy, biomotor
Treatment
 Convalescent & sequela period
 acupuncture
 massage
 exercise etc.
Prevention
 isolating patients and pig immunization,
 killing mosquito and preventing mosquito ,
 vaccination:
killed virus vaccine: 60~90%
病例分析
5岁患儿，8月15日开始发热头痛，呕吐
一次，次日排稀便两次，精神不振，第
三天晚间开始抽搐，神志不清。查体，
T40℃，急病容，脉充实有力，呼吸略促，
节律整，皮肤无瘀点、瘀斑，颈强(+)，
克氏征(+)，肢体肌张力增强。辅助检查：
病例分析
血WBC 15×109／L，便常规WBC 0～5个／
Hp， CSF细胞数75×106／L，糖
3.5mmol/L,氯化物115mmol/L，蛋白
0.45g/L
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治疗要点