Infectious CPC

Question 1

most common arbovirus

Answer 1

1) west nile
2) st louis
3) eastern/western equine

all live in tick vector
can cause epzootic infections

Question 2

west nile virus pathogenesis reaching brain

Answer 2

1) mosquito bites you
2) replicates in langerhans cell
3) dendritic cell go to infect
macrophages and WBC
4) go to blood —> viremia
5) enters CNS
6) also go to spleen with secondary viremia

Question 3

ratio of asymp-WN fever- CNS disease with WNV infection

Answer 3

80% asymp

20% west nile fever

Question 4

meningoencephalitis symptoms

Answer 4

1) fever, HA, nuchal rigidity
2) n/v/neck pain
3) low back pain
4) parkinsonism and tremor
5) myoclonus
6) flaccid paralysis via anterior horn disease
7) CN palsy
8) cerebellar signs

Question 5

neuroimaging of WNV infection

early vs later

Answer 5

early = MRI normal

later = abnormalities in deep gray nuclei (thalamus, basal ganglia, midbrain, brainstem)

Question 6

WNV encephalitis
dx method

CSF WNV

Answer 6

LP WNV IgM = IgM made in brain

PMN pleocytosis
reactive lymphocytes (plasma cells)
incr protein
normal glucose

if PCR positive, then diagnositc but rare

Question 7

therapy for WNV

Answer 7

ribavirin makes worse

US IVIG
Interferon a 2b

Question 8

most common cause of sporadic vs epidemic encephalitis

Answer 8

HSV= sporadic
WNV = epdiemic

Question 9

clinical method of meningitids diagnosis

Answer 9

1) blood culture + empiric treatment for bacteira +/- antiviral for HSV2
2) LP = viral (aseptic) or bacteiral CSF
3) imaging before #2 but usu neg
4) if viral, likely = enterovirus, HSV2, WNV

Question 10

clinical method of encephalitis diagnosis

Answer 10

1) MRI = mass lesion or other brain involvement?
2) LP = viral or bact CSF profile
3) empiric antiviral for HSV1 +/- antibiotics