10 Neuropathology (CNS infections)

Question 1

Name the 4 routes via which infectious agents can enter the CNS

Answer 1

• hematogenous
• direct implantation
• local extension from adjacent site of infection
• axoplasmic transport along peripheral nerve axons

Question 2

Bacteria and yeast most often cause what type of meningitis?

Answer 2

pyogenic or granulomatous

Question 3

Hyphal forms of fungi most often cause ____ and _____

Answer 3

cerebritis

abscesses

Question 4

T/F- bacterial is the most common type of CNS infection and results in meningitis more frequently than abscess

Answer 4

true

Question 5

Viral infections usually cause what?

Answer 5

encephalitis, meningoencephalitis

Question 6

Describe the CSF findings in bacterial pyogenic meningitis

Answer 6

many neutrophils
high protein
low glucose

Question 7

Describe the clinical symptoms of bacterial pyogenic meningitis

Answer 7

headache
altered mental state-encephalopathy
increased intracranial pressure
seizures

Question 8

What 2 organisms cause acute (purulent) meningitis in neonates

Answer 8

Group B strep

Listeria Monocytogenes

Question 9

What 3 organisms cause acute meningitis in young children

Answer 9

N. meningitidis
Strep pneumoniae
H. influenzae (unvaccinated)

Question 10

What 2 organisms cause acute meningitis in older children/adults?

Answer 10

Strep. pneumoniae

Neisseria meningitidis

Question 11

T/F- in bacterial meningitis you’ll likely see pmns in leptomeninges

Answer 11

true

Question 12

Name 2 complications of meningitis

Answer 12

infarcts

chronic hydrocephalus

Question 13

Lymphocytic meningitis (aka aseptic/viral) is usually self limited. What will you see in the CSF?

Answer 13

lymphocytes
moderately high protein
Normal glucose

Question 14

Name 2 most common causes of lymphocytic/aseptic meningitis

Answer 14

echovirus

coxsackie virus

Question 15

Name 3 causes of chronic (granulomatous) meningitis

Answer 15

1. M. tuberculosis/avium
2. Yeast forms of fungi (cryptococcus, coccidioides, blastomyces)
3. rarely sarcoidosis

Question 16

What is a feared complication of chronic meningitis?

Answer 16

obliterative endarteritis leading to infarction of underlying brain

Question 17

chronic meningitis has a predilection for _____

Answer 17

base of brain

Question 18

What bacteria commonly cause cerebrates and abscess in the brain?

Answer 18

Anaerobic strep
Strep pneumoniae
Staph sp.

Question 19

What fungi cause cerebrates and abscess of the brain?

Answer 19

aspergillus
mucor
candida

Question 20

What protozoal infection can cause cerebrates and abscess of the brain?

Answer 20

toxoplasma

Question 21

What is the most common method of pathogen “spread” leading to cerebritis and abscess?

Answer 21

Direct spread (50%)
hematogenous spread (25%)

Question 22

Rank the following from most to least common location of brain abscess: parietal, cerebellum, frontal

Answer 22

Frontal»parietal>cerebellum

Question 23

What is cerebritis?

Answer 23

focal infection/inflammation before an established abscess (with a wall) forms

Question 24

T/F- abscesses present as a ring enhancing lesion on CT

Answer 24

true

Question 25

What type of pathogen (virus, bacteria, etc) is most often responsible for encephalitis?

Answer 25

viruses

Question 26

Will you see microglial nodules and neuronophagia with viral encephalitis?

Answer 26

yes

Question 27

Rabies: ____ body inclusion Herpes: ____ body inclusion

Answer 27

negri body | cowdry type A

Question 28

What virus causes progressive multifocal leukoencephalopathy?

Answer 28

JC virus

Question 29

In HIV encephalitis, you'll often see multinucleated giant cells located where?

Answer 29

around vessels

Question 30

in PML you'll see bizarre, atypical ______ as well as intranuclear inclusions in ______ cells

Answer 30

1. astrocytes (reactive, not neoplastic) | 2. oligodendroglial cells

Question 31

Is toxoplasmosis a ring enchancing lesion?

Answer 31

yes

Question 32

In spongioform encephalopathy are the vacuoles in the white or gray matter?

Answer 32

gray

Question 33

Classic triad of symptoms in prion diseases?

Answer 33

rapid dementia myoclonus periodic short wave activity on EEG

Question 34

Are most cases of CJD sporadic or familial?

Answer 34

most are sporadic | only 10-15% familial

Question 35

What chromosome is the normal gene for protease resistant prion protein on?

Answer 35

chrom20

Question 36

Describe the pathogenesis of prion disease

Answer 36

- Disease occurs with conformational change of PrP 3D structure into ß-pleated sheet - Single pathogenic PrP can induce further protein conversions of wild type protein creating a chain reaction - PrP accumulates in and outside of cells in the form of amyloid

Question 37

Is there a mutation that increase your risk for sporadic CJD?

Answer 37

Homozygosity for Met or Val at codon 129 increases risk of sporadic CJD

Question 38

T/F- CJD brain will always show atrophy

Answer 38

false, may look normal or may show atrophy

Question 39

Describe the microscopic appearance of CJD

Answer 39

Neuronal loss, gliosis, and spongiform change (often patchy), defined by small “punched out” vacuoles in gray matter (cortex ± deep nuclei)