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Flashcards in Viral CNS infxn Deck (68):
1

Viral Meningitis

Usually mild and self-resolving

2

Bacterial Meningitis

Life threatening

3

Predictors of bacterial etiology regarding meningitis?

- Low CSF glucose
- High CSF protein
- High CSF white count
- High CSF neutrophil count

The presence of any one of these predicts bacterial etiology with 99% certainty

4

Viral meningitis appearance

- Pts don't appear extremely ill, are NOT ENCEPHALOPATHIC
- fever and malaise
- headache
- neck stiffness
- low back pain

Usually lasts 10-14 days
Recurrent viral meningitis can result from persistent or latent infections (HSV)

5

Most common cause of Viral Meningitis?

Enteroviruses....80%

6

What are some of the enteroviruses that cause viral meningitis?

echo, coxsackie, enterovirus 71

7

10% of viral meningitis caused by

Mumps

8

How are enteroviruses spread

oral/fecal route

9

HSV-2 generally causes

genital herpes

Can also be a cause of RECURRENT aseptic meningitis

10

Mollerat cells in the CSF?

HSV-2

11

HIV and VZV cause?

recurrent meningitis

12

30% of viral encephalitis caused by

Arboviruses (arthropod born viruses) such as St. Louis, West Nile, La Crosse

Transmitted by mosquitos and ticks
Predominantly affects the children or the elderly

13

25% of viral encephalitis caused by

Enteroviruses (echo, coxsackie, entero 71)

14

25% of viral encephalitis caused by

Herpes Simplex 1

15

What is important to recognize about HSV-1

It is a deadly cause of encephalitis if not treated promptly with acyclovir

16

Clinical course of viral encephalitis

fever
headache
lethargy
URI
Confusion
then.... seizures, coma, death in some cases

If you see Fever, headache, lethargy and a prodromal URTI...think encephalitis

- Looks exactly like bacterial meningitis so you MUST treat it empirically before you really even know what the diagnosis is

17

What is the prognosis associated with mosquito born viruses?

poor

18

What is the characteristic site of damage in HSV encephalitis?

Temporal lobe....MRI shows necrosis in temporal lobe

19

Diagnosis of HSV1?

PCR is definitive but false negatives occur

20

Mortality without tx for HSV1

70%

21

Flaviviruses

St. Louis and West Nile

22

Flavivirus morphology

Small, enveloped, +RNA viruses

23

Flavivirus replication cycle

1) Enters by receptor mediated endocytosis
2) + strand genome is translated into single polyprotein, that polyprotein is cleaved.
3) virions bud into intracellular organelles and are transported via the eocytotic pathway and released

24

All members of the flavivirus genus are transmitted how>

through insect vectors....They are the most important group of arboviruses

25

Flaviviruses that cause disease in the US

- St. Louis, West Nile, Dengue fever, Yellow Fever

SWDY

26

Disease course of flavivirus

Virus replicates at the site of inoculation.

Initial infection = primary viremia (mild fever, chills, aches)

Usually cleared by reticuloendothelial system (spleen, liver, etc..)

Continued replication can give rise to a secondary viremia which can invade CNS. Generally would only occur in children, elderly, or immunocompromised

27

SLE ( St. Louis Encephalitis) syndromes and symptoms slide

SLE found in north, central, and south america

- Onset characterized by flu-like symtpms, most do not progress. If secondary viremia occurs, it can lead to acute or subacute neurological signs and symptoms associated with CNS disease.

28

Primary host for west nile

birds

29

Vector for west nile

mosquitos

30

West nile disease symptoms and treatments

- Febrile, influenza like illness with abrupt onset
- moderate to high fever
- headache, sore throat, backache, myalgia, arthralgia, fatigue
- Rash, lymphadenopathy
- Acute aseptic meningitis or encephalitis
- most fatal cases occur in the elderly

31

Most significant cause of arbovirus encephalitis worldwide?

Japanese Encephalitis Virus

32

Vaccine available for JEV?

yes....people who are going to spend at least a month in a rural area should be vaccinated

33

Togaviridae includes what viruses

Rubella and Alphaviruses

34

Togaviridae morphology

small, enveloped, nonsegmented, positive stranded RNA virus.....like flavi

35

One genera of togaviridae is alphavirus which incldes

western, eastern, and venezuelan equine encephalitis

All transmitted by mosquitoes

36

Alphavirus symptoms

- ranges from asymptomatic to terrible
- Encephalitis generally seen in young and old
- Adults get mild disease with fever and drowsiness

37

ALphavirus vaccine?

reserved for lab workers and military.
Vaccines for horses used extensively

38

Bunyavirus morphology

enveloped, single stranded negative sense RNA

39

Two kinds of bunyavirus we need to know

california encephalitis virus
La Crosse virus

40

MOst common cause of arboviral induced pediatric encephalitis in US

LaCrosse

Pretty low mortality rate though

41

Rabies Virus (Rhabdoviridae) morphology

enveloped, nonsegmented, - RNA

Bullet shaped morphology

42

Rhabdoviruses have a single membrane glycoprotein called G which is both the attachment protein and the fusion orotein

ok...Low pH induces membrane fusion

DO NOT INDUCE SYNCYTIA

43

Rabies the disease

Slow progressive disease that characteristically involves the CNS. Why? Because the rabiesvirus glycoprotein has a neurotropism

- Rabies initially replicates only in the neuronal cells but then disseminates to other organs

- found in high concentrations in the salivary glands during the final stages of the disease

44

incubation period of rabies

anywhere from 1 week to 2 months depending on bite site (how close it is to the CNS)

45

Rabies replicates in muscles and then travels through nervous system to brain

3 phases of rabies disease development
1) prodromal period: 2-10 days following exposure includes malaise fever and headache
2) Acute neurologic phase: can occur months to years after initial exposure, nervous system dysfunction,

46

Know LCMV

Enveloped, segmented, ambisense RNA viruses. Virions contain two RNA segments
- Enter by pH dependent pathways

Transmission occurs by inhalation of aerosolized rodent excreta and saliva.

The disease is characterized by two phases. The initial phase shows a prodrome of fever, headache, nausea, and vomitting
Aseptic meningitis appears two days later. ....rarely fatal

47

Epidural abscess signs and symptoms

- Point tenderness
- Elevated ESR which is a non-specific index of an inflammatory process.
- Elevated white count

48

Tumor destroys bone but spares disc,

infection involves the disc but spares the bone

49

A key feature of the back pain associated with spinal epidural abscess?

Worsening pain on recumbency, because the venous plexus that drains teh lower thoracic and lumbar vertebrae has no valves when you are lying down

50

Bowel and bladder dysfunction mean?

There is a 24-48 hour window in which treatment can save the spinal cord

51

Failing to recognize spinal epidural abscess is one of the top 10 reasons that doctors are sued for malpractive

so is bacterial meningitis and subarachnoid hemorrhage

52

Most common pathogen for spinal epidural abscess

Staph

53

Rocky Mountain Spotted Fever causative organism

Rickettsia

54

Describe Rickettsia

Gram negative intracellular anaerobe
- attack vascular endothelial cells
- cause systemic vasculitis
- transmitted by ticks

55

RMSF signs and symptoms

Fever, headache, flu-like symptoms 3-14 days after a tick bite

Early petechial rash in distal extremities, rash moves proximally

56

Lyme disease

Neuroborreliosis
- spirochete transmitted by ticks
- Rare in memphis
- Target skin rash at the bite site (erythema migrans)...gradually expands over the next few days
- Within weeks pts experience flu-like symptoms, acute arthritis, heart block, headache, stiff neck,

57

3 stages of syphillis

Primary- painles genital chancre 3 weeks after infection

Secondary- 2-3 weeks after chancre, macular-papular rash on PALMS, SOLES and body, adenopathy, iridocyclitis, arthritis, meningitis or meningo-vascular stroke

Tertiary: If untreated, skin, cardio, and neuro complications arise after 15-20 years.

58

Who is at high risk for meningitis and stroke due to secondary syphillis

immunocompromised

59

What is the CSF profile for an HIV pt with neurosyphillis

Positive serum FTA (fluorescent treponemal antibody)

Positive CSF VDRL

If FTA is positive but the CSF VDRL is negative, one diagnosis probably neurosyphillis as long as their is CSF pleocytosis (inc white cell count) and elevated CSF protein

60

If untreated, TB can produce

Granulomatous meningitis that is especially severe at the base of the brain. Can entrap multiple cranial nerves and block CSF flow, causing hydrocephalus and raised ICP

61

Chronic meningitis clinical symptoms

- fever
- headache
- lethargy
- poor appetite/wt loss
- cranial neuropathy
- personality change
- cognitive impairment

62

In addition to meningitis, TB can cause

vasculitis with vessel thrombosis and brain infarcts

63

Early clinical features of TB Meningits

confusion
lethargy
low grade fever
headache vomitting

64

How do you confirm the diagnosis of TB

- one option is a new RNA PCR test
- you also want to isolate the org from the CSF though

65

CNS TB treatment

BIG THREE plus one (IRP + strep or eth)

Isoniazid, Rifampin, Pyrazinamide

Plus streptomycin or ethambutol

66

main risk for zoster

Ulceration of the cornea

67

HSV-1 encephalitis responds to

acyclovir

68

CMV encephalitis responds to

ganciclovir