Viral CNS Infections

Question 1

Two primary ways that viruses get into the CNS?

Answer 1

Blood and Neurons

Question 2

What is meningitis?

Answer 2

Inflammation of the lining of the brain

Question 3

What is Encephalitis?

Answer 3

Inflammation of the brain tissue

Question 4

What is Meningoencephalitis?

Answer 4

Widespread infection of the meninges and brain

Question 5

What is encephalopathy? Common cause?

Answer 5

Damage to brain tissues: Prions

Question 6

What is aseptic meningitis?

Answer 6

Meninges are inflamed and pyogenic bacterial source is not to blame; Infectious bug cannot be determined.

Question 7

What are typical causes of aseptic meningitis? What is the most common type of viral infection?

Answer 7

Virus, fungi, TB; Enterovirus (90%)

Question 8

Describe lumbar puncture findings of aseptic meningitis

Answer 8

Increased WBCs but no CSF

Question 9

What Tx is used for aseptic meningitis?

Answer 9

Not many options but few options for herpes, fungal, and mycobacterial infections

Question 10

What is Brudzinski’s sign?

Answer 10

Lift patient’s head upward when in the supine position and knees will bend up indicating meningitis

Question 11

Describe the general progression of encephalitis

Answer 11

Virus (generally) -> influx of immune cells in brain -> Cerebral edema destroys neurons -> Hemorrhage

Question 12

What are some urgent Syx of encephalitis?

Answer 12

Unresponsive/Coma, Seizures/Weakness/Paralysis, Memory Loss/Flat Affect/Withdrawal/Poor Judgement

Question 13

How do you diagnose encephalitis?

Answer 13

Spinal tap indicates inflammation in CSF, blood (possibly), PCR for viruses; EEG/MRI/CT

Question 14

What is the treatment for encephalitis? If herpes?

Answer 14

Supportive care/Syx relief, sedate (phenytoin), anti-inflamm/reduce edema (dexamethasone); Acyclovir

Question 15

What are typical complications of meningitis? Encephalitis?

Answer 15

Generally benign, resolve in 2 wks; Permanent neurologic ipairments to memory, speech, vision, hearing, muscle control, or sensation

Question 16

What are risk factors for viral CNS infection?

Answer 16

• Age (older)
• Immune status (Immunoincompetent)
• Genetics (Innate resistance of viruses)
• Exercise (may increase dissemination of virus)

Question 17

What is Acute Disseminated Encephalomyelitis (ADEM)?

Answer 17

Postinfectious encephalitis following viral infection by 1-2 wks; possibly autoimmune etiology

Question 18

What are the Alphaherpesviruses?

Answer 18

HSV-1/2, VZV;

Question 19

When can herpetic meningitis occur?

Answer 19

In both primary and recurrent infections

Question 20

What is the most common herpes virus that causes meningitis? What are other less frequent offenders?

Answer 20

HSV-1/2; VZV, CMV, EBV;

Question 21

Tx for herpesvirus meningitis?

Answer 21

Acyclovir, valaciclovir, famciclovir

Question 22

Describe the dessemination of Rabies Virus. Why is this relatively easy to treat?

Answer 22

Inoculated within an injured site -> Replicated w/i muscle -> Travel up nerve (slowly) -> Brain; It is so slow!

Question 23

How is rabies spread? What does the virus have a tropism for?

Answer 23

Through salivary glands! or organ transplants!

Question 24

What is the transmission of picornaviruses? Who does it affect? What are two to major Picornaviruses and which one are we currently worried about? What do we have a vaccine for?

Answer 24

Fecal-oral; Young children (mild disease), Old children, adult (asymp - paralytic); Polio and entero; Only to Polio

Question 25

What is the general rount of dissemination of picornavirus?

Answer 25

Mouth -> Oral/GI Mucosa -> Blood -> Brain

Question 26

What is the general circulating pattern of Arboviruses? What are the dead end hosts?

Answer 26

Betwixt birds and mosquitos; Horses and humans

Question 27

Name 4 Togaviruses

Answer 27

Venezuelan equine encephalitis, Eastern Equine Encephalitis, Western Equine Encephalitis, Chikungunya virus

Question 28

What are the subtypes of arbovirus we should know about?

Answer 28

Togavirus (WEE, VEE, EEE, Chikungunya) and Flavivirus (Japanese Encephalitis, St. Louis Encephalitis)

Question 29

When during the year are arboviruses most common?

Answer 29

Summer months

Question 30

How are arboviruses spread?

Answer 30

Mosquito

Question 31

Describe the basic pathogenesis of prion disease

Answer 31

Proteins (Prions) misfold -> aggregate -> fibril formation -> Disease (May come from exogenous causes as well)

Question 32

What is the major etiology of CJD? 2nd most? 3rd?=

Answer 32

Sporadic; Genetic; Iatrogenic

Question 33

Describe the pathology found in CJD? Time frame? Prognosis?

Answer 33

Brain atrophy, spongiform pathology; Dementia, loss of brain fn., 6-9 months until dead;

Question 34

Describe the Dx process for CJD

Answer 34

MRI (only suggestive), 14-3-3 protein in CSF, post-mortem analysis (autopsy general way to make Dx)

Question 35

Describe precautions for prion diseases. What are the highest risk body parts?

Answer 35

Currently all surgical/medical equipment is thrown out/incincerated; Brain, spinal cord, eye tissue

Question 36

What is a distinguishing feature of encephalitis?

Answer 36

Intracerebral hemorrhage

Question 37

What type of viral encephalitis would a patient likely get in the summer?

Answer 37

Enterovirus

Question 38

What is the route other than viremia where a virus may disseminate to the brain?

Answer 38

Retrograde transport from peripheral nerve endings or nasal mucosa!