Viral Meningitis Flashcards
Which is more common, viral or bacterial meningitis?
VIRAL much more common!
Recurrent viral meningitis, look for:
Persistent/latent infxns: HSV1/2
Viruses causing meningitis:
Enterovirus (80%): Echovirus, Coxsackie virus, Enterovirus 71
Mumps: RARE due to MMR vacc. May be seen in idiots who do not vaccinate their kids.
Recurrent aseptic meningitis: HSV2, HIV, Varicella Zoster
Viruses causing encephalitis:
Arboviruses- genus flaviviridiae (30%): trans. by mosquitos/ticks, seasonally
Enteroviruses: familial epidemics due to URI, GI infxns
HSV-1 (30%): tx w/ acyclovir!
What are the Flaviviruses (Arboviruses) we need to keep in mind concerning encephalitis?
West Nile, St. Louis, Japanese Enceph. virus
Pestiviruses
HCV
Flaviviruses use host or virally encoded machinery for replication?
Host Ribosomes translate RNA genome
Viral/Host proteases for cleavage of polyprotein
Viral polymerase to replicate genome
Describe how Flaviviruses make it into the brain to cause encephalitis from the blood stream.
Arthropod vector deposits virus into blood stream of human.
Replicates in endothelium. –> primary viremia
1 wk later, replicates in macrophages, spleen, lymphnodes.
Results in mild systemic disease (most infxns STOP here)
If infxn continues in immunocompromised host—> 2ndary Viremia—> Encephalitis
PCR confirms that your pt has St. Louis encephalitis. What is the prognosis?
How should you treat this?
50% survive the week
20% survive beyond 2 weeks.
Supportive care. No vaccine/tx available
PCR confirms your pt has West Nile virus infxn. What is the prognosis?
How do you treat this?
Most cases are mild dz.
Rarely, stupor–> coma—> death
Supportive care. No vaccine/tx available
Your pt is traveling to SE Asia for 3 months on business. You recommend they get vaccinated to prevent contracting:
Japanese Encephalitis Virus. MOST SIGNIFICANT WORLDWIDE!
Also, prob not a bad idea to get some penicillin G, Bactrim, and 3rd gen Ceph and Z-pack prophylaxis for syphilis, the Clap, and the Yella Stank, respectively. Bc come on, business? I THINK NOT.
Togaviridiae =
Equine (Horse) viruses!
Either you have a fever and get over it, or it KILLS YOU IN 2 WKS!
Bunyaviruses, what are they?
Prognosis?
CA encephalitis virus
La Crosse virus
Good prognosis.
Pt MIGHT have Rabies. What do you do?
Symptoms may not present for MONTHS.
Give human IgG in/around wound site and 5 course vaccine (far from wound site bc it inactivates IgG) to ALL suspected victims IMMEDIATELY.
This virus replicates by the unconventional “ambisense” strategy:
Arenaviridiae- Lymphocytic ChorioMeningitis Virus (LCMV)
How do you contract Arenaviridiae (LCMV)?
Aerosolized rodent excreta/saliva. Don’t hang out around sneezing bats unless you want LCMV.
Although it is rarely fatal. Most pts recover w/o serious neurological deficits.
