Types of viral encephalitis Flashcards
what part of the brain is affected by viral encephalitis
brain parenchyma
what are the most frequent etiology of viral encephalitis
Arbovirus
HSV-1
What is the key in signs and symptoms of viral encephalitis
to determine whether signs and symptoms is focal or diffused
what are etiologic agents of diffused encephalitis besides arbovirus
HSV1
non-polio enterovirus
what are etiologic agents of focal encephalitis besides HSV-1
arbovirus
non-polio enterovirus
rarely polio virus or rabies
if one of the viral encephalitis agents produces an asymptomatic infection does the infection spread to the CNS
NO
What are togaviridiae group of arbovirus
comprised most arthropod-borne virus, also rubella
what are categories of togaviridae
Alphavirus and flavivirus
what are examples of alphaviruses
EEEV, WEEV, VEEV
what are examples of flavivirus
SLEvirus
WNEvirus
POWvirus
what are examples of bunyavirus
Hantavirus
California Virus, Jamestown canyon virus, LaC virus
where is the highest incidence of California encephalitis serogroup
California, Midwest, SE U.S.
what are examples of reoviridae
rotovirus, CLTFvirus
arbovirus causes what two primary syndromes
hemorrhagic fever
encephalitis/meningitis
what is the seasonality of arbovirus
varies annually, peak in summer months when animals are out
what is the primary cause of epidemic encephalitis
arbovirus
what are the principle arthropod vectors
mosquitoes and ticks
what are CLFV and POW virus spread by and what about the rest
ticks
Rest is spread by mosquitoes
what are the principle reservoir of arbovirus
birds and small mammals
how is arbovirus transmitted to humans
tangent transmission
what is the age and gender relationship in arbovirus
primarily children others in elderly
N/A gender
what is the seasonality of arbovirus
sporadic epidemic occur in summer months when reservoir vector and humans are out doors
what is the RF for arbovirus in individuals
summer exposure to mosquitoes and ticks, age
for creation of arbovirus epidemic what is needwed
large reservoir (birds), large vector (mosquitoes), favorable climate
how do you monitor the arbovirus activity in the US
sample mosquitoes,
wild birds are captured and bleed
sick dying animals are observed
what is the pathogenesis of arboviris
primary viral replication causes none/mild symptoms
secondary replication causes viremia attacks brain and other organs
what is the most common clinical manifestation of arbovirus
asymptomatic infection most common result
what are possible disease outcomes of arbovirus
self-limiting flu
self-limiting aseptic meningitis
encephalitis and death +/- flaccid paralysis
how do diagnose arbovirus
CSF
Serological
EEG
CT
what is the treatment of arbovirus
supportive
what is the prevention of arbovirus
goal is limiting the vector population and education and precaution (DEET)
What type of immunity is there against arbovirus
specific and life long
2 vaccines for horse
US military vaccine against EEV and WEEV
what geographical location does EEEV predominate
East Coast , wooded areas near swamps and marshes
what arbovirus has the worst mortality rate and more likely to manifest with neurological sequelae
EEEV
How is EEEV unique to other arboviruses
asymptomatic is not the norm. Norm is Eastern Equine Encephalitis
what geographical location does WEE predominate
west of Mississippi River highest in rural residence
what age does most WEEV occur
50% in children <1yo
what arbovirus is the most benign form of encephalitis
WEEV
what geographical location does SLEV predominate
Midwest
What age does most SLEV occur
varies due to herd immunity
Children in West
Elderly in East
what is the leading cause of epidemic arboviral encephalitis before WNEV in 2002
SLEV
What agent does WNEV relate to
SLEV
what is the geographic distribution of WNEV
Africa, Europe, middle east, west Asia, Australia. North america
what is the most common arbovirus in the US today
WNEV
how else can WNEV be transmitted beside mosquitoes
transfusions, in utero
what are s&s of West Nile Fever
flu symptoms, muscle aches, nausea, maculopapular rash, frontal HA, eye pain
what are S&S of West Nile Encephalitis
West nile fever with at least one of the following:
meningitis, encephalitis, parkinsonism, focal muscle weakness
what is treatment of WNEV
Ribavirin useful in vitro
where does CAL serogroup predominate
California, East of Mississippi
What is the age relationship in CAL serogroup
almost all occur in children and adolescents
what is the most important cause of arbovirus pediatric encephalitis in the USA
LAC
what symptom of CAL serogroup is unique and can occur as a sequelae
siezures
what is poliomyelitis
acute infection systemic infectious disease destroying motor neurons in the spinal cord results in flaccid, ascending, asymmetrical paralysis
what is the morphology of Polio virus
enterovirus, non-enveloped, + sense RNA virus
which serotype of Polio virus is responsible for most of the paralytic polio
type 1
what serotype of Polio virus is often isolated in vaccine-associated poliomyelitis
types 2 and 3
why is Polio virus rare in us today
vaccine
what was the original though of Polio virus
disease of developed countries in older populations, but child and young adults present with serious disease
where is paralytic polio still a significant concern
underdeveloped counyties
what is the transmission of Polio virus
fecal oral route through water. Virus in stool for 3-6 weeks
less so through respiration (oral-oral)
what is the host of Polio virus
humans
what are the reservoir of Polio virus
humans and water
how infectious is Polio virus
highly communicable
what population is primarily infected by Polio virus
<3yo children, but young adults, prego, and elderly can be susceptible as well
what is the relationship with severity of polio/paralytic polio and age
severity and chance of getting paralytic polio increases with age
what is the seasonality of polio
summer-fall
what is the pathogenesis of Polio virus
incubation is long
infected cells train to lymph nodes along GI, first pharynx then intestine, shed in resp. weeks shed in feces for months
is Polio virus lytic or lysogenic
lytic
what is a rare occurrence of Polio virus in the body
entering cns is rare
what happens if Polio virus enters cns
but if it does it spread through neural routes and pns like rabies and herpes destroys nerve fiber pathway
results in flaccid paralysis with no sensory lose (unlike GBS)
what is the most common clinical syndrome in Polio virus
asymptomatic
what are signs of minor poliomyelitis
fever, malaise, HA, muscle aches, pharyngitis, nausea, abd pain, constipation last 72 hours
what are signs of aseptic meningitis in Polio virus without paralysis
signs of minor poliomyelitis and
pain in neck, back, and leg
muscle stiffness and tenderness or spasm lasts 1-2weeks
what are signs of paralytic poliomyelitis
initial like aseptic meningitis
paralysis after that complete by fever break, muscle spasms, loss of superficial and deep tendon reflex, abnormal sensations
what are three forms of paralytic poliomyelitis
spinal
bulbar polio
bulbospinal polio
what is post polio syndrome
survivors of paralytic polio fatigue, new muscle weakness/pain, progressive atrophy
happens in 30-40yo not activation of latent virus but to over use
how do you diagnose Polio virus
stool sample
PCR
partial genomic sequencing of stool
what is the treatment of polio virus
supportive
what is the prevention of polio
vaccine, IPV, eIPV
what is needed after Polio virus vaccine especially in developing countries
booster, 4th booster in developing countries
how does oral polio vaccine differ from parental polio vaccine
oral is live attenuated. can put unvaccinated at risk
what is rabies
acute, fatal. fulminant, focal encephalitis and myelitis
what are characteristic of rabies
rhabdoviridae, lyssavirus, -ssRNA, bullet shaped
how many serotypes of rabies
1
what is a negri body
eosinophilic cytoplasmic inclusions of viral nucleoptoteins
what is the incidence rate of rabies
low because of control of cats and dogs
what is the transmission of rabies
animal bite or scratch
what is the reservoir of rabies
dogs cats, skunks, fox, racoon. bat, wolves others
what is the geographic distribution of rabies
in the us, rabies is epizootic
what is the age/gender relationship in rabies
NONE
what is the seasonality of rabies
NONE
what are RF of rabies
uncontrolled animals
what animal is the most common source of rabies in US
bats
what is pathogenesis of rabies
virus enters PNS at unmyelinated sensory terminals and nm junctions
retrograde axoplasmic flow to spinal cord then brain
what part of the brain does rabies predominate
gray matter , but localizes in limbic system
when is a rabies pt potentially infectious
from 2 weeks before onset of symptoms to death
what is the point of no return for rabies
moment the virus enters sensory terminals and NM junctions
Can the rabies virus be isolated in blood
no
what is the prodrome of rabies
flu like symptoms for 2 to 4 days
what length of rabies disease is always fatal
5 to 6 days
what forms of rabies disease cab be seen
paralytic/dumb form
Excititation-furious form
What is paralytic/dumb rabies
signs are similar to viral encephalitis
paralysis extremity to trunk
hypoventilation and hypotension to coma and death
what is excitation-furious rabies
photo/phonophoba
hyperactivity sexual agressive, agitation anxiety, insomnia. confusion, foaming at mouth to coma and death
which rabies form is more common
excitation-furious rabies
how is rabies diagnosed
csf, DFA of cytoplasmic inclusions, isolation of virus via mouse inoculation
what is treatment for rabies
none
wat is prevention of rabies
vaccination pre and post exposure
where should you never inject rabies vaccine
gluteal injections
what should you do after exposure
clean wound, tetanus prophylaxis, Vaccination AND antiserum two diff sites
what agent cause 20% of all cases of viral encephalitis in the US and most common cause of all non epidemic/ sporadic focal encephalitis
HSV
who does HSV have peak incidence in
nenates with infected mother
young adults/elderly via reactivation of latency
what is the transmission of hsv
saliva, vagina secretion (esp. post partum), semen
in utero but rare
what is the pathogenesis of hsv
spread to the CNS by retrograde axoplasmic flow
is hsv lytic or lysogenic
lytic
what is hsv manifestation in adults
focal encephalopathy in one lobe usually temporal.
memory defect, psychosis, slurred speech, personality changes
relapse and death is high
in adults primary genital herpes infections can result in?
a benign, aseptic meningitis
what are the 3 possible presentations of HSV in neonate
Local herpes infection, SEM
Disseminated
CNS disease
what is the etiologic agent in bells palsy
hsv and vsv
how is hsv diagnosed
symptoms presentation
CSF- viral glucose protein levels, mononuclear pleocytosis and lost of RBCs
Other Tests
what is treatment for hsv
antivirals and nucleoside analogs, not a cure
where is the most common hsv infection in children from infected mother
intrapartum
how is hsv diagnosed in pregnant women
clinical exam plus one of the following
Swab- PCR or viral culture
or Serology for type specific AB test
what is tx of hsv in prego women
suppressive on in last 4 weeks of pregnancy
acyclovir daily
discuss delivery stategy
Csection if virus was aquired 3rd trimester or lesion is present
What does HAND stand for
HIV associated neurocognative disorders
what does HAD stand for
HIV associated dementia
what is HAND
it is a slowly progressobe demylenation of disease with neuronal loss of the CNS
what is the incidence of cns disease of HIV pts pre-HAART
60% will show evidence of neuropathy
what is RF of HAND
IVDA even despite HAART
what is a good prognostic indicator of pts who have HAND
plasma and viral load supression
what is the pathogenesis of HAD
direct infection of cns and pns occurs early in HIV infection
what cells does HIV replicate and infect in HAD pathology
monocyte, macrophage, microglia of CNS
what cells does HIV not infect
neurons and oligodendrocytes
hiv in the CNS is M-trophic which utilizes which receptor as a cofactor
CCR5
what is hiv related neuronal damage due to
gp120 or Tat proteins
HAD is NOT due to
autoimmune, lymphoma, infection (other than HIV of course)
HAD is characterized by
, astrocytosis, micrglial nodules, diffuse or focal myelin pallor or neuronal loss
what are manifestation of of HIV associated CNS
peripheral neuropathy, aseptic meningitis, acute encephalitis, HIV motor complex, vacuolar neuropathy, sensory pain of feet
what is asymptomatic neurocognative impairment (ANI)
impairments seen through testing but are symptomatic in their daily life
what is HIV associated mild neurocognative disorder (MND)
impairments causing mild disturbances in daily life
what Hiv associated cns disease is more common in the new area of HAART
ANI -> NMD
what type of changes are seen in HAD pts
Early: Cognitive, Motor, Behavioral
Late: Progression, mute, spasticity, death
how is hiv associated cns disease diagnosed specifically HAD
if pts have one or more (pleocytosis, abnormal CSF ig recoverable HIV in CNS)
Use HAD Scale
what should imaging studies show in HAD
cortical atrophy, enlarged ventricles , demylenation of white matter, abscence of focal abnormalities
what is the treatment of CNS HIV disease
HAART, could cause increase in sensory neuropathy and should be able to cross BBB
what does PML stand for
progressive multifocal leukoencephalopathy
what kind of disease is PML
uncommon, subacute, progressive demyelination of CNS
what is the etiologic agent in PML
papovavirus
what is the morphology of papovavirus
naked dsDNA with icosahedral symmetry
what are examples of papovavirus
Polymavirus (JC virus, BK virus, SV40)
HPV
what is the result of PML in immunocompetant
common asymptomatic infection
what percentage of people world wide are positive for BK virus
60-90%
how can JC and BK virus become fatal
underlyining disorder which causes reactivation of virus through immunosuppression
what does BKV cause
a fatal opportunistic kidney disease in renal transplant pts
or severe UTI in HIV
what does JCV cause
a rare opportunisitic CNS reactivation of disease in advanced HIV/AIDS and pts on Natalizumab
what is the pathogenesis of JCV
invades oligodendrocytes cause cell death and causes infection along the myelin tract and infects astrocytes
what virus is present in most pediatric brain tumors
JVC
what part of the brain is most affected by JVC
subcortical white matter
what would cells would be affected by JVC
abscence of oligodendrocytes, abnormal astrocytes, sparing of neuron and axons, enlarged oligodendritic cells with inclusions
INFLAMMATORY CELLS ARE ABSENT
What are the clinical manifestation of JVC disease
Rapid, Muscle weakness, ataxia, cognitive/speech impairments, visual loss
how do you diagnose pml
clinical signs, PCR of CSF, Neuroimaging of demyelnation, pathology seen in brain biopsy
what is the tx for pml
cidofovir
HAART in aids pts.
Prognosis good if HAART is started when CD4>100
