Micro: Greenberg 3 Flashcards
What are the clinical hallmarks of encephalitis?
confusion, disorientation, acute changes in ideation and thought
What will CSF exam of viral meningitis show?
elevated WBC, usually w mononuclear pleocytosis of lymphocytes, normal or elevated protein, normal glucose
What is the microbiology of enteroviruses?
small nonenveloped RNA called picornaviruses
includes coxsackie A & B, echovirus, polio, enterovirus 71 (brainstem encephalitis)
humans only natural hosts, most common cause of viral meningitis
How are enterviruses spread?
fecal oral - poor hygienic environments, day care
resistant to pH, detergents and disinfectants, heat and sewage treatment
household spread common
most common in SUMMER (jun-Oct)
How is enterovirus diagnosed? Treated?
PCR
most resolve spontaneously, only few have sequelae, no current treatment or vaccine
maybe ISG for neonates and immunocompromised, interferon alpha
What are the clinical manifestations of enterovirus?
non-specific febrile illness, respiratory illness, hematologic conjunctivitis, herpangina (mouth blisters), hand-foot-mouth syndrome, pleurodynia, myocarditis, meningitis, encephalitis, congenital/neonatal inf
What is HSV type II meningitis?
sexually transmitted
pts have typical presentation and lab findings of viral meningitis
What is Mollaret’s meningitis?
benign recurrent aseptic meningitis - symptoms resolve w/i 5 days and pt recovers without sequelae
LP consistent w viral meningitis
mostly caused by HSV2 - only minority have genital herpes
prophylactic acyclovir
Which types of transmission/syndromes are caused by which type of HSV?
HSV type 1 = encephalitis, respiratory
HSV type 2 = meningitis, sexually transmitted
How is HSV encephalitis diagnosed?
mostly in temporal lobe
CSF PCR - false negative if hemoglobin or other inhibitors present –> repeat PCR 1-3 days later
What are the four main clinical syndromes of poliomyelitis?
asymptomatic: viral replication limited to oropharynx and gut
minor illness: nonspecific febrile illness, headache, malaise, sore throat, usually prompt resolution
nonparalytic aseptic meningitis: resolves w/o seqeulae
secondary viremic spread to nervous system –> flaccid paralysis
What is the diagnosis/treatment/prevention of polio?
CSF findings of aseptic meningitis
no antiviral therapy - maintain fxn
2 types of vaccine - live attenuated (IgA and GALT but not used anymore) and killed (only IgG)
What is the cycle of HSV-1 inf causing HSE?
after acute inf causes latent in trigeminal ganglion - reactivates and replicates - some fibers innervate meninges adjacent to temporal lobe
What is the virology of west nile virus?
member of flavivirus family
+sense ssRNA
belongs to japanese encephalitis virus group - St. Louis also a member
When does St. Louis encephalitis cause disease?
late summer and early fall - dz primarily in older people
What are the clinical manifestations of St. Louis encephalitis?
coarse tremors (inv of substantia nigra)
muscular weakness rare
transient parkinson like tremor
How is St. Louis encephalitis/WNV diagnosed?
serologically off blood and CSF, demonstrate presence if IgM
What are the clinical syndromes associated w WNV?
vast majority just have asymptomatic or febrile syndrome
neuroinvasive = meningitis, ecephalitis, meningoencephalitis, or polio-like syndrome
older individuals affected predominately, acute flaccid paralysis
What clinical manifestations help distinguish WNV from St. Louis encephalitis?
tremor if basal ganglia involved but mild and in minority in WNV
muscular weakness profound in WNV
What are factors involved in neurotropic WNV?
upregulation of genes involved in IFN signalling, T cell recruitment, MHC class I and II antigen presentation, apoptosis HTN and vascular dz may predispose
What is the vector control for WNV?
aerosols don’t affect aquatic stages of mosquitos
mortality restricted to “adults” in flight
graded drainage systems
fix poorly constructed apts
What is the treatment and prevention for WNV?
no effective vaccines for humans or antiviral agents
looking for protease inhibitors
MyD88 inhibits by inhibiting replication in subset of cells
vaccine for horses
What kind of virus is the rabies virus?
RNA rhabdovirus
What is the cycle of the rabies virus once it enters the body?
binds to peripheral nerves - spreads retrograde back up to the brain - affects hippocampus, brainstem, pons, Purkinje cells of cerebellum - disseminates along nerves to salivary glands and other cells
What is the clinical progression/stages of inf with rabies?
incubation period - most variable in length
prodromal phase - fever, lethargy, vomiting, anorexia, headache, pain at bite - 2-10 days
neurological stage - loss of coordination, paralysis, delirium, confusion (hypersalivation, hydrophobia)
coma and death - almost invariably fatal
How is rabies diagnosed?
late, viral antigen in CNS
can be isolated and cultured but only after neurological dz
brain biopsy - Negri body = intracytoplasmic inclusions of viral nucleocapsid
What are the two cycles of reservoirs of rabies? the two forms?
urban - dogs main transmitters
sylvatic - large number of hosts
encephalitic, paralytic
What is the prevention of rabies?
vaccine - pre-prophylactic for high risk, prophylactic post-exposure - also give hyper-rabies immunoglobulin (HRIG) - *not effective once symptoms develop
How is anti NMDA receptor encephalitis diagnosed?
mild CSF lymphocytic pleocytosis
T2 FLAIR hyperintensities
tumors often found
What are the treatment and prognostic factors for anti NMDA receptor encephalitis?
most respond to immunotherapy (steroids, IVIG, plasmapheresis) second line (rituximab, cyclophosphamide) recovery can take up to 10 months, 3/4 do recover
What is postinfectious encephalitis?
after viral inf (VZV), most commonly children, winter or spring
characterized by multi-focal perivenous demyelination (CD8 cells, autoimmune)
ADEM not consequence of specific inf or immunization
outcome usually favorable, 30% will develop MS
What are signs and symptoms of postinfectious encephalitis?
meningeal signs
multi focal neurologic signs raise suspicion of ADEM
MRI w gadolinium enhancement
What is the virology of JC virus and PML?
polyoma family (includes BK and SV40) predominately in pts w advanced AIDs related to papillomaviruses
What is subacute sclerosing panencephalitis?
associated w prior measles inf
recover, then 6-15 yrs later progressive neurological degeneration
intact viral particles not present, but particles lacking M protein and viral nucleic acids detected
no treatment, usually death
What is Reye’s syndrome?
encephalopathy (not encephalitis) associated with inf viral illness
influenza B and varicella mostly
has acute fatty liver
linked to use of aspirin
