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Flashcards in CNS Infections Deck (77)
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1

What can an untreated CNS infection cause?

Brain herniation and death
Cord compression and necrosis with subsequent permanent paralysis

2

What does the gross morphology of pyogenic (bacterial) meningitis show?

Thick layer of suppurative exudate covering the leptomeninges over the surface of the brain
Exudate in basal and convexity surface

3

What does pyogenic meningitis show microscopically?

Neutrophils in the SA space

4

What is the DDx for fever and altered mental status?

Encephalitis
Meningitis
Meningoencephalitis
Encephalomyelitis
Severe sepsis syndrome due to infection elsewhere

5

When does viral meningitis usually present?

Late summer/autumn

6

What causes viral meningitis?

Enteroviruses e.g. ECHO virus
Other microbes and non-infectious causes also

7

How is viral meningitis diagnosed?

Viral stool culture, throat swab and CSF PCR

8

What is the treatment for viral meningitis?

Supportive as self-limiting

9

What viruses can cause viral encephalitis?

HSV (serious)
VZV
CMV
HIV
Measles

10

What is the treatment of HSV encephalitis?

Aciclovir IV high doses- must be recognised, admitted and treated within 6 hours

11

What is the history and treatment of VZV encephalitis?

History of shingles
High dose acyclovir

12

What are the travel related causes of viral encephalitis?

West Nile, Japanese B encephalitis, Tick Borne encephalitis

13

What are the occupational related causes of viral encephalitis?

Rabies

14

What are the non-infectious causes of viral encephalitis?

Autoimmune etc

15

What are the clinical features of encephalitis?

Insidious onset-sometimes sudden
Meningismus
Stupor, coma
Seizures, partial paralysis
Confusion, psychosis
Speech, memory symptoms

16

What investigations are required in viral encephalitis?

LP
EEG
MRI

17

If there is a delay in investigations in suspected viral encephalitis what should be done?

Start pre-emptive acyclovir as prompt therapy improves outcome

18

What are the MRI findings in encephalitis?

Inflamed portion of the temporal lobe, involving the uncus and adjacent parahippocampa I gyrus (brightest white on MR)

19

What are the common causes of bacterial meningitis related to age?

Neonates: listeria, group B streptococci, E. coli
Children: H. influenza
10 to 21: meningococcal
21 onward: pneumococcal >meningococcal
Elderly: pneumococcal>listeria

20

What are the common causes of bacterial meningitis related to RFs?

Decreased CMI: listeria
S/P neurosurgery or opened head trauma: Staphylococcus, Gram Negative Rods
Fracture of the cribiform plate: pneumococcal

21

What is the likely causative organism in bacterial meningitis due to an immunocompromised state?

S. pneumoniae
N. meningitidis
Listeria
aerobic GNR (including Ps.aeruginosa)

22

What is the likely causative organism in bacterial meningitis due to a basilar skull fracture?

S. pneumonia
H. influenzae
beta-hemolytic strep group A.

23

What is the likely causative organism in bacterial meningitis due to head trauma or post-neurosurgery?

S.aureus
S.epidermidis
aerobic GNR

24

What is the likely causative organism in bacterial meningitis due to a CSF shunt?

S. epidermidis
S. aureus
aerobic GNR
Propionibacterium acnes

25

What can be some long term effects of meningitis and septicaemia?

Limb loss
Deafness
Blindness
Cerebral palsy
Quadriplegia
Severe mental impairment

26

What is the pathogenesis of bacterial meningitis?

1. Nasopharyngeal colonisation
2.Direct extension of bacteria: parameningeal foci (sinusitis, mastoiditis, or brain abscess), across skull defects
3. From remote foci of infection: (e.g. endocarditis, pneumonia, UTI etc)

27

What are some agents of meningitis in immunocompromised patients?

Conventional agents- s.pneumonia, s.aureus etc
Listerio monocytogenes
Mycobacterium tuberculosis
Nocardia asteroides
Cryptococcus neoformans (AIDS)

28

What does Neisseria meningitides cause?

Meningococcal meningitis

29

What are the symptoms in meningococcal meningitis due to?

Endotoxin from bacteria

30

In whom does Meningococcal meningitis most commonly occur?

Young children