Microbiology and Immunology - Viral Meningitis - Jennifer Moffat Flashcards
Is aseptic meningitis caused by bacteria?
No
Causes: viruses, funghi, TB, infections near the CNS
What is the most common cause of aseptic meningitis?
Enteroviruses (80%)
then HSV 1 and 2 and arboviruses
What is the distinguishing feature between encephalitis and meningitis?
Mental status remains normal in meningitis;
Intracerebral hemorrhage can happen in encephalitis but not meningitis
Symptoms of meningitis:
photophobia, headache, fever, malaise, stiff neck, chills, sore throat, nausea, vomiting, abdominal pain, rash, muscle pain
What WBC count is expected in aseptic meningitis?
Elevated WBC
glucose normal
viruses may be detected in CSF
What is Brudzinski’s sign?
Sign of meningitis
Neck is so stiff that knees flex when neck is flexed
CNS infections include alphaherpesviruses and rabies, which spread in what way?
Neuronal spread ie trigeminal nerve in HSV-1
CNS infections include enteroviruses (a kind of picornavirus) which spread in what way?
Fecal-oral
CNS infections include arboviruses (flaviviruses, togaviruses) which spread in what way?
Insect vectors
Which herpvesvirus is most likely implicated in meningitis?
Primary HSV-2
How would you best diagnose HSV-1 encephalitis?
PCR of CSF
MRI shows predominantly unilateral temporal lobe abnormalities
How does rabies travel neuronally?
Replicates at bite site in muscle
Infects peripheral nerves and travels to the brain
Spreads to salivary glands
Why is post-exposure immunization preventative against rabies?
Rabies has a long incubation period, weeks to months
Where does poliovirus replicate?
tonsils and Peyer’s patches (lymphoid tissue)
(+) sense
RNA virus
naked
acid stable
These are characteristics of what virus?
Poliovirus AND Coxackie A and B, all picornaviruses
What is the only picornavirus not spread fecal-orally?
Rhinovirus (droplets/fomites)
**is acid labile, can’t get through GI tract
How does rhinovirus enter host cells?
ICAM-1 receptor
What are the distinguishing symptoms of coxsackie B virus?
Dilated cardiomyopathy
“Devil’s grip” / Bornholm’s disease/ Pleurodynia - unilatera, trouble breathing
Can cause aseptic meningitis, encephalitis
common in summer months
What are the distinguishing symptoms of coxsackie A virus?
hand, foot and mouth disease - red vesicular rash
common in summer months
Can cause aseptic meningitis, encephalitis
What is ADEM (Acute disseminated encephalomyelitis)?
- -Postinfectious encephalitis following viral viral infection by 1-2 weeks
- -Associated with measles, mumps, VZV, influenza, parainfluenza viruses
- -can be associated with autoimmune disorder
VEE
EEE
WEE
are all examples of:
Togaviruses that cause encephalitis
Japanese encephalitis and St. Louis encephalitis are examples of:
Flavaviruses
West Nile patients who are at higher risk of developing WNV meningoencephalitis include:
Cancer
Diabetics
HTN
Kidney disease
Viral infections of the CNS cause meningitis, encephalitis, or both, and have many common symptoms. What is a distinguishing characteristic of encephalitis?
A. Virus detected in CSF by culture or PCR
B. Intracerebral hemorrhage
C. Stiff neck, aka Brudzinski’s sign
D. Headache
E. Prognosis may be good, with few sequelae
B. Intracerebral hemorrhage
A patient diagnosed with viral encephalitis in the summer is most likely infected with what type of virus?
A. Enterovirus B. CMV C. HSV-2 D. Rabies virus E. Mumps
A. Enterovirus
Viremia can result in skin rashes, congenital infections, and CNS infections. What is an alternate route for viruses to enter the CNS?
A. Extravasation through the meningeal or cerebral capillaries
B. Implantation of an organ from a donor infected with HSV-1
C. Retrograde transport from peripheral nerve endings or nasal mucosa
D. Bites from Aedes, Culex or Culiseta mosquitos carrying togaviruses
C. Retrograde transport from peripheral nerve endings or nasal mucosa
Which type of HSV-1 is more likely to be associated with meningitis, HSV-1 primary or recurrent infection?
Recurrent HSV-1 infection
