Viral infections of the Nervous System Flashcards
natural host of LCM virus (lymphocytic choriomeningitis)
Mus musculus
causes fifth disease in young children characterized by high fever and markedly flushed cheeks, irritability and sometimes febrile seizures
in adult may cause brachial neuritis
Parvovirus
may be associated with cauda equina neuritis
HSV and HIV
HVS- with preceding genital infection with the virus
causes encephalitis in immunocompromised patients
HIV, chemo for neoplasm, organ transplantation or hematologic or lymphoid malignancy
HHV-6
CMV
VZV
Vogt-kayanagi-Harada syndrome
iridocyclitis
depigmentation of a thick swath of hair and of skin
vitiligo aorund eyes, loss of eyelashes, dyacusis, deafness
Most serious among the arbovirus infections In the US
eastern equine encephalitis (EEE)
predilection of lesions in Herpes Simplex Encephalitis
inferomedial or lateral portions of the frontal and temporal lobes, and insula
T/F Lesions in HSE are usually bilateral and always symmetrical.
False
usually bilateral but not symmetrical
p751
T/F
In the acute stages of HS encephalitis, intranuclear eosinophilic inclusions are found in neurons and glia cells in addition to the usual microscopic abnormalities of acute encephalitis and hemorrhagic necrosis.
True
p751
EEG findings in Herpes Simplex Encephalitis
lateralized periodic high-voltage sharp waves in the temporal regions and slow-wave complexes at regular 2-3/s intervals
T/F
In HSE, False-negative tests for HSV PCR are most likely to occur in the first 72 hrs of febrile infection.
False
48 hrs
p752
Dose and duration of Acyclovir in HSE
30mg/kg/d
10-14 days
Main cause of relapses in HSE in adults
treatment with low doses for a brief period
prognosis in Herpes Simplex Encephalitis
if treatment begun 4 days of onset of illness, survival is greater than 90%
in an evaluation after 2 yrs, 53% were dead or severely impaired
Neurologic sequelae in HSE
korsakoff amnesic defect or global dementia
seizures
aphasia
causative agent in roseola
exanthemia subitum
HHV-6
viral agents that appear as causes of encephalitis with some regularity in stem-cell and organ transplants pts
parvovirus CMV EBV adenovirus HSV VZ virus
incubation period for Rabies
10-20 days, as short as 14 days
main neurologic symptoms for rabies include apprehension, dysrathria, psychomotor overactivity, followed by dysphagia, spasms of throat muscles, dysarthria, numbness of the face, diplopia, spasma of facial muscles indicate involvement of
tegmental medullary nuclei
Rabies is distinguished by the presence of cytoplasmic eosinophilic inclusions called
Negri bodies
most prominent in the pyramidal cells of hippocampus and Purkinje cells
Focal collections of microglia in Rabies are called
Babes nodules
Dose of Human Rabies immune globulin HRIG for postexposure prophylaxis
20 U/kg
provides passive immunnization for 10-20 days
Acute ataxia of childhood is most often associated with
chickenpox
most common causative organisms to cause acute ataxia in adults
varicella, EBV, mycoplasma
characterized clinically by radicular pain, vesicular cutaneous eruption, segmental sensory and delayed motor loss
Herpes Zoster
VZV DNA is localized primarily in which ganglia
trigeminal
thoracic
Lipschutz inclusion bodies are seen in
herpez zoster
multiplication of virus in epidermal cells causes swelling, vacuolization, lysis of cell boundaries, leading to the formation of vesicles
how long does pain and dysesthesia usually last in Herpes Zoster
1-4 weeks
in others - pain persists for months or years
what to look for in Tzanck smear
multinucleated giant cells in scrapings from the base of an early vesicle
thoracic dermatomes frequently involved in herpes zoster
T5 - T10
followed by craniocervical regions
complication of VZV
2-10 weeks after onset of ophthalmic zoster, patient develops an acute hemiparesis, hemimanesthesia, aphasia or other focal neurologic or retinal deficits associated with mononuclear pleocytosis in the spinal fluid and elevated IgG in CSF
cerebral angiitis
in Zoster angiitis
Acyclovir shortens the duration of acute pain and speeds the healing of vesicles provided that treatment started within approximately how many hrs?
48 hrs
some say 72
Zoster angiitis
for immunocompromised patients, what is the treatment
intravenous acyclovir given for 10 days
Treatment for Toxoplasmosis in AIDS
pyrimethamine 100mg initially then 25 mg daily
sulfonamide 4-6g daily
Nonfocal complication in AIDS
presenting with retinitis, acute confusional state or delirium combined in a small proportion of cases with cranial nerve signs including ophthalmoparesis, nystagmus, ptosis, facial nerve palsy or deafness
Cytomegalovirus
Early histopathologic changes in poliomyelitis
anterior horn cells - central chromatolysis of the nerve cells
along with an inflammatory reaction
Prion encephalopathy or all types has now been firmly associated with the conversion of a normal cellular protein PrPc to
an abnormal isoform, PrPsc
True or False
in prion encephalopathy
The transformation involves a change in which its helical proportion diminishes and the proportion of Beta pleated sheet increases.
True
p770
In CJD
Several competing classification systems have been devised that are based on both the presence of what two amino acids at codon 129 of the prion protein
methionine
valine
which of the ffg is the most common variant in spongiform enceph
a. MM1
b. MM2
c. MV1
d. VV1
MM1
rapidly or subacutely progressive and profound dementia is associated with diffuse myoclonic jerks
early stages of neurologic disease are characterized by a great variety of clinical manifestations, changes in behavior, emotional response, intellectual function followed by ataxia and abnormalities of vision such as distortions of shape and alignment of objects or impairment of visual acuity
early phase: confusion, hallucinations, delusion, agitation
CJD
EEG pattern in CJD
distinctive and changing over the course of disease from diffuse and nonspecific slowing to one of stereotyped high-voltage slow 1-2Hz and sharp-wave complexes on an increasingly slow and low-voltage background
In CJD EEG
the high-voltage sharp waves which give the appearance of periodicity are synchronous with
myoclonus but the pattern may persists even without myoclonus
MRI findings in CJD
hyperintensity of lenticular nuclei on T2 and DWI when disease is fully established
long contiguous segments of cortex as well as various parts of BG also show these alterations
what parts of the brain are mostly affected in CJD
major neuropathologic changes are found in:
cerebral and cerebellar cortices
in CJD
the microscopic vacuoles, which gives the brain tissue the typical sponge appearance are found in
cytoplasmic processes of glia cells and dendrites of nerve cells
how viruses gain entrance to the body
VZV, measles and mumps -
polioviruses, enteroviruses -
HSV -
VZV, measles and mumps - respiratory
polioviruses, enteroviruses - oral-intestinal
HSV - oral or genital mucosal route
intermediate step to seeding in the brain/CSF
viremia
viruses which utilize the peripheral nerve pathway
VZV
rabies
HSV
In Progressive multifocal leukoencephalopathy, there is a selective lysis of
oligodendrocytes
clinical syndrome of aseptic meningitis
fever, headache, signs of meningeal irritation
predominantly lymphocytic pleocytosis in the spinal fluid with normal glucose
mild depression of CSF glucose (nerve below 25mg/dL) occurs with meningitis caused by
mumps
HSV-2
lymmphocytic choriomeningitis
VZV
most common cause of aseptic meningitis
viral
mostly enteroviruses - mainly echovirus and Coxsackie virus
Elsberg syndrome
associated with HSV2
aseptic meningitis
bladder failure
vaginal or vulvar pain after a bout of genital herpes
Most common sporadic cause of encephalitis and has no seasonal or geographic predilections
HSV
primary infection with EBV, complicated by meningitis, encephalitis, facial palsy, or polyneuritis of the GBS
infectious mononucleosis
T/F
Status epilepticus in Herpes Seimplex Encephalitis is common.
False
rare
p751
pathologic lesions in Herpes Simplex Encephalitis
intense hemorrhagic necrosis of the inferior and medial temporal lobes and the mediorbital parts of the frontal lobes
region of necrosis may extend upward along the cingulate gyri and sometimes the insula or the lateral parts of teh temporla lobes or caudally into the midbrain but always contiguous with areas of mediotemporal lobe necrosis
route of entry of HSV into the CNS
latent in trigeminal ganglia and with reactivation may infect the nose and then the olfactory tract
may also soread along nerve fibers that innervate the leptomeninges of the anterior and middle fosaee
imaging findings in Herpes Simplex Enceph
CT - hypodensity of the affected temporal lobe areas in 2/3 of cases
MRI - increased signal in T2 weighted images
T1- low signal intensity with surrounding edema and sometimes scattered areas of hemorrhage occupying the inferior parts of the frontal and temporal lobes
ehancement to some degree with contrast: indicates cortical and pial abnormalities of BBB
T/F
Antiviral treatment seems to affect PCR assay results in cases of herpes simplex encephalitis.
False
antiviral treatment did not appear to affect the results.
p752
establishes cause of a medial temporal lobe (limbic) encephalitis in adult patients following allogenic hematopoeietic stem cell bone marrow transplants
HHV-6
T/F
One attack of zoster provides lifelong immunity.
False
p755
hazard in ophthalmic herpes
herpetic involvement of cornea and conjunctiva resulting in corneal anesthesia and residual scarring
syndrome
facial palsy in combination with a herpetic eruption of the external auditory meatus
Ramsay Hunt Syndrome
takes the form of a slowly or subacutely progressive dementia accompanied variably by abnormalities of motor function
treatment with antiretroviral drugs can result in cognitive improvement
AIDS Dementia Complex
sensitive tools in the early stages of AIDS dementia complex except trail making CDT pegboard symbol-digit testing
except CDT
test of psychomotor speed seem to be most sensitive in the early stages of dementia
pathologic basis of dementia
diffuse and multifocal rarefaction of teh cerebral white matter accompanied by scanty perivascular infiltrates of lymphocytes and clusters of a few foamy macrophages, microglial nodules, multinucleated giant cells
pathologic description of HIV myelopathy
vacuolar degeneration
with pathologic resemblance to subacute combined degeneration because of vitamin B12 deficiency
antiretroviral drug that can cause myopathy
zidovudine
because of its effect on the mitochondria
p760
MRI findings in CMV in AIDS
T2 hyperintesities in the periventricular regions may extend more diffusely in the white matter and be accompanied by meningeal enhancement by gadolinum
Shingles involving several contiguous dermatomes is known to occur in AIDS with CD4 counts
below 500
T/F
Poliomyelitis
Inclusion bodies can be seen in the spinal cord.
False
p764
No inclusion bodies
T/F
Acyclovir or famciclovir can be given to patients with poliomyelitis.
False
p764
The authors know of no systemic study of the potency of antiviral agents in this disease.
mortality from acute paralytic poliomyelitis
5-10%
in polio, the return of muscle strength occurs mainly in the first ___ months
3-4 months
p765
probably the result of morphologic restitution of partially damaged nerve cells
history of primary measles infection at a very early age, before 2 years
followed by a 6-8 year asymptomatic period
initially, decline in proficiency at school, temper outbursts, changes in personality, difficulty with language, loss of interests in usual activities
progressive intellectual deterioration, focal or generalized seizures, widespread myoclonus, ataxia, visual disturbances, progressive chrorioretinitis
Subacute sclerosing panencephalitis
EEG in SSPE
periodic (every 5-8s) bursts of 2 to 3/s high voltage waves, followed by a relatively flat pattern
T/F
Cerebellum is usually affected in SSPE.
false
usually spared
p766
develops several days to weeks
personality changes, intellectual impairment
combination of hemiparesis progressing to quadriparesis
visual field defects, cortical blindness, aphasia, ataxia, dysarthria, , dementia, confusional states, coma
seizures are infrequent
develops in patient with a neoplasm or chronic immunodeficiency state
CSF - normal
CT and MRI - nonenhancing demyelinating lesions
Progressive Multifocal Leukoencephalopathy
Prognosis in PML
death occurs in 3-6 months
causative agent in PML
JC virus
human polyomavirus
a CD4 count of _______ is a poor prognostic sign for recovery from PML
100 cells /uL
ophthalmoplegia and pronounced somnolence
1/3/ bradykinesia, catalepsy, mutism, chorea, myoclonus
20% died within a few weeks, survivors have varying degrees of impairment of mental function
most extraordinary feature: parkinsonian syndrome after an interval of weeks or months
Encephalitis Lethargica
von Economo Disease, Sleeping Sickness
T/F
Prion diseases may be both genetic and infectious.
True
p769
outstanding neuropathologic changes in CJD
widespread neuronal loss and gliosis accompanied by a striking vacuolation or spongy state of the affected regions
subacute spongiform encephalopathy
Prion encephalopathy has now been firmly associated with the conversion of a normal cellular protein PrPc to an abnormal isoform PrPsc - the transformation involves a change in conformation of the protein - describe the change in number of helical and beta pleated sheets
the helical proportion diminishes and the proportion of beta pleated sheets increases
test of CSF in CJD - finding by immunoassay of peptide fragments of normal brain proteins termed
14-3-3
