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CNS Infections- Viral
Viral Infections of CNS- from Moscatello
65
Microbiology
Professional
04/26/2012

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Cards

Term
Name 3 ways in which viruses cross the blood brain barrier:
Definition
Growing across it
Being passively transported across it in intracellular vacuoles
Being carried across by WBCs
Term
What is the receptor for measles?
Definition
CD46
Term
What is the receptor for polio?
Definition
CD155PVR
Term
What is the receptor for HSV?
Definition
Heparin sulfate, TNF receptor
Term
What is the receptor for rabies?
Definition
AChR, NCAM
Term
What is the receptor for HIV?
Definition
CD4+CCR5 or CXCR4
Term
What is hematogenous entry and what two types of viruses can do this?
Definition
Directly into blood stream
Arboviruses- mosquito injection
Rabies- from a bite
Term
What is neural entry into the CNS, and what viruses do this?
Definition
Spread from distal neural structures to CNS-
Rabies, HSV, VZV
Travel up ganglia
Term
What are the symptoms of frontal lobe abscess?
Definition
Frontal sinusitis
Headache
Memory defects
Attention loss
Diminished intelligence
Term
What are the symptoms of temporal lobe encephalitis?
Definition
Personality changes, visual field defects, hemiparesis (with large lesion), focal seizures
Term
What are the symptoms of basilar meningitis?
Definition
Headache- suboccipital
Neck stiffness
Diplopia
Cranial Nerve palsy
Term
What are 3 important aspects of the immune response to CNS pathogens?
Definition
-inflammation->edema->tissue death
-decreased capillary perfusion to brain
-neurological symptoms
Term
What is the main class of enteroviruses, and how are they spread?
Definition
Picornaviridae- SMALL RNA VIRUSES- fecal-oral transmission without symptoms of diarrhea
Term
What changes do we see in CSF in bacterial infection?
Definition
Highly elevated PMNs
Protein above 100
Glucose less than 45
Term
What changes do we see in CSF in viral infection?
Definition
Presence of lymphocytes/monocytes
Protein 50-100
Normal Glucose (Esper said differently)
Term
What are the classic symptoms of viral meningitis?
Definition
Fever, nuchal rigidity, photophobia, headache
-irritability, nausea/vomiting, rash, weakness x 18-36 hours
Term
How long does viral meningitis usually take to clear?
Definition
Self limiting withing 7-10 days
Term
What virus causes Hand Foot and Mouth disease?
Definition
Coxsackie A
Term
What virus causes viral myocarditis?
Definition
Coxsackie B
Term
What class of virus is polio? Describe it?
Definition
Enterovirus
+ stranded RNA, non-enveloped
Spread fecal-oral
Term
What viruses are estimated to cause >85% of all meningitis?
When are we more likely to see these cases?
Definition
Non-polio enteroviruses
Warmer months
Think coxsackie A and B
Term
What are some symptoms associated with enterovirus meningitis (besides the main meningitis symptoms)?
Definition
Pharyngitis, pleurodyna (pain in pleura), rash, pericarditis
Term
Describe Arboviruses generally and what they cause:
Definition
Postive stranded enveloped RNA viruses
Mosquito vector borne
Cause ENCEPHALITIS (and sometimes meningitis)
Term
What is the most common arbovirus in the US?
Definition
Saint Louis Encephalitis (SLE)
Term
What is the most common arbovirus worldwide?
Definition
Japanese B
Term
What is the most common clinical manifestation of arbovirus infection?
Definition
Meningoencephalitis instead of pure aseptic meningitis
Term
Why are seizures more common in arbovirus infection?
Definition
Because they cause encephalitis too
Term
Describe mumps and its most important permanent effect:
Definition
Mumps- negative stranded RNA virus- helical- ENVELOPED
Meningitis is a common complication
Causes Bilateral Parotitis (chipmunk cheeks)
CAN CAUSE STERILITY IN MALES (orchitis)
Term
What virus is the leading cause of encephalitis?
Definition
HSV-1
Term
Which herpes is responsible for genital infections and neonatal meningitis?
Definition
HSV-2
Term
Describe the structure of herpes viridae:
Definition
DNA virus; Icosahedral; ENVELOPED
Term
When is VZV CNS infection most common?
Definition
Zoster REACTIVATION
Term
What drug should be given immediately upon suspicion of herpes viral infection?
Definition
Acyclovir IV
Term
What are two ways in which viral encephalitis can be prevented?
Definition
Mosquito eradication
Sanitation
Term
Your patient presents with obvious infectious lesions of the temporal lobes and obvious visible vesicular outbreak on their face. What is your best guess for the causative agent?
Definition
HSV
Term
Your patient presents with a rash and encephalitis. You notice the rash covers a distinctive/definable region. What is your best guess for the causative agent?
Definition
VZV- shingles
Term
Your patient presents with a bite and neurological symptoms. What is your best guess for a causative agent?
You slay the offending animal and look at its brains. What do you find?
Definition
Rabies
NEGRI BODIES
Term
When is a patient most likely to acquire herpes encephalitis?
Definition
On REACTIVATION of HSV-1
Term
Where does HSV-1 reactivate and where does it infect?
Definition
Usually reactivation in the trigeminal ganglia
Infects temporal lobe
Term
What characterizes an "intermediate" host?
Definition
Lower viral titers, difficult to spread
A "dead end" for the virus
Term
Where on earth would you find arboviruses in their highest titre form?
(tricky question)
Definition
Mosquito salivary glands
Term
What aspect of a patient history is super important in cases of encephalitis?
Definition
Travel history
Term
Describe the structure of the rabies virus:
Definition
Negative stranded RNA virus
HELICAL, ENVELOPED
BULLET SHAPED
Term
What does rabies cause?
Definition
Acute, progressive, incurable and DEADLY encephalitis
Term
What 4 animals most commonly transmit rabies in the US? Worldwide?
Definition
Racoons, bats, foxes, skunks

Worldwide= dogs
Term
How long is the incubation period for rabies?
Definition
1-3 months
Term
How does rabies travel in the CNS?
Definition
RETROGRADE TRANSPORT
Term
Describe the path of travel of the rabies virus in an infected person:
Definition
From the brain, the virus returns to the periphery, to the salivary glands (which are highly innervated)
Term
What are the symptoms of rabies?
Definition
Fever, chills, headache, difficulty swallowing, HYDROPHOBIA
Hallucination, disorientation, paralysis, coma, death
Term
Describe the prodrome of rabies:
Definition
Flu-like
Term
How does rabies eventually kill the patient?
Definition
Cardiac or respiratory arrest
Term
How is rabies diagnosed?
Definition
Perivascular cuffing
Skin biopsy, corneal impression, brain biopsy with PCR/IF
NEGRI BODIES
Term
How is rabies treated?
Definition
Clean the wound, VACCINATION (only time we vaccinate after exposure)
Half in the wound, half IM
Confirm if animal is rabid
Term
Describe the structure of HIV:
Definition
Positive stranded RNA RETROVIRUS
Enveloped
Term
Describe the course of HIV encephalitis
Definition
Invades CNS shortly after initial infection- pleocytosis in CSF, mild meningitis like illness
Later subacute encephalitis with dementia
Term
Describe the pathology of HIV related dementia:
Definition
Brain shrunken with enlarged ventricles
Vacuolization of myelin tracts
Virus infects the macrophages (microglia) in the CNS
Term
What does mumps encephalitis usually follow?
Definition
Parotitis (7-10 days)
Term
What virus causes subacute sclerosing pan encephalitis (SSPE)?
Definition
Measles
Term
What characterizes the pathology of subacute sclerosing pan encephalitis?
Definition
Progressive neurological deterioration due to brain inflammation and nerve cell death
Term
What are some symptoms of SSPE?
Definition
Behavior changes, intellect/memory issues, movement issues, gait problems, seizures, speech difficulty, dysphagia
Term
What causes myelitis?
Definition
POLIO- replication in neurons of gray matter of brain and spinal cord
FLACCID PARALYSIS without sensory loss
Term
What is affected in bulbar polio?
Definition
Respiratory muscles, medulla oblongata
Term
What are the two types of polio vaccine and which can revert to virulent strain?
Definition
Salk- Killed
Sabin- Live- can revert
Not used in US anymore
Term
What viruses that cause encephalitis can be revealed by a Tzanck test?
Definition
Herpes, VZV
Term
What virus causes Progressive Multifocal Leukoencephalopathy, and in what patient population?
Definition
JC Virus- immunocompromised patients
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