Introduction To Encephalitis Flashcards
What are a significant causes of encephalitis?
Autoimmune
Post infection
50% are idiopathic
What are some characteristics of encephalitis?
Seizures (common poor prognosis)
Fever
Cerebral defects
What are some clinical evidences of encephalitis?
Altered level of consciousness for more than 24hrs
At least two of the following:
Fever or a history of
Seizures and/or focal neurological defects
CSF pleocytosis
Imaging
Why is there a wide range of geographical encephalitis?
Microorganism have higher prevalences in winter
Arvoviruses need vectors so you need humans to live by those vectors
Westnile and such
Arthropod born sometimes?
Only 5 per 100000 per year
What is the biggest known cause of encephalitis?
Herpes simplex (HSV-1,2)
What is the biggest class of viruses that cause encephalitis?
Herpes virus alpha
What is a post infection cause of encephalitis?
Measles
What do you consider with diagnosis of encephalitis?
Fever Seizures Coma White blood cells in CSF CT scan MRI (ADEM, and post infections)
What is the empiric treatment when encephalitis is thought to exist?
Acyclovir for alpha herpes virus
IV administration
What should CSF be tested for when thinking encephalitis?
PCR WBC Protein Glucose Serum for post infection antibodies
What is temporal lobe involvement a sign of?
HSV infections
What do flaviviruses target in the brain?
Basal ganglia and thalamus
What are the WBC for viral encephalitis?
High lymphocytesw
Where is the site of latency for alpha herpes viruses?
The neuron
What are characteristic for alpha herpes virus?
Skin
Lymph node
Spleen liver respiratory
What are some characteristics on HSV 1 and 2?
Icosaherdral nucleocapsid Enveloped Ds linear genome Simplex Viral DNA defendant DNA polymerase Proteins are major target Cell mediated
How do you tell HSV 1 and 2 apart?
1 - typically above the waste
2 - below the waste, neonatal
Both cause encephalitis
50% of known causes
Where do you get a HSV infection?
The mouth
Beaten back into the trigeminal ganglion
What is the most common cause of encephalitis in immunocompromized patients?
Zoster
Second cause in spontaneous encephalitis
What is acyclovir?
Like a base g Ribose sugar Precursor until it gets phosphorylated Need thymidine kinase for initial phosphorylation Need herpes for this Uses this to replicate viral genome DNA chain inhibitor
What is a acyclovir like drug for beta herpes viruses?
Gancylcovir
They do have another kinase
What is a caveat of these cycloid drugs?
They only treat ongoing infections
What is ADEM and the causes?
Acute disseminated encephalomyelitis
Demyelinating disease by measels, mumps, rubella, zoster, influenze
What are some characteristics of measels virus?
Ssdna negative
Group 5
Helical capsid
Enveloped
What is the path of infection of the measles virus?
Spread through the air Mucus mem Lymph nodes Blood organs Whole process is 10-14 days
What do you need to mount a good immune response against the measles?
INF-alpha
IL-2
If you don’t have them you niger neurological problems
What is primary measles encephalitis?
Rare
During initial infection
What is subacute sclerosing panencephalitis?
Can occur 3-20 years you see problems
Before age of 2 is greatest risk
Slow infection
Behavior function is low
How often does primary measles encephalitis occur?
1-3 out of 1000 Pxs
Supportive treatment
Survivors have neurological damage
What is acute disseminated encephalomyelitis?
APME
Occurs 1 out of 1000
Results in demyelination
Weeks to months later
What is the treatment of APME?
Anti inflammatory drugs
What about enteroviruses?
Picornavirus
Fecal to oral with occasion hit to brain
What are two main arboviruses?
Westnile
Le crosse encephalitis virus
Flu like
What are characteristics of rabies encephalitis infection?
Uncontrollable spasms of the throat
Death is due to respiratory paralysis
What is the diagnosis of rabies encephalitis?
Obervation of Negri bodies
What is the treatment of rabies?
Passive immunity RIG immune globulin buying time for vaccine
Vaccine is injected at the bite intramuscularly
