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Flashcards in CNS infections - cellular pathogens Deck (33):
1

In which age group do CNS infections most commonly occur?

0-4 years

Paediatric disease 

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2

In which age group do CNS infection have the highest mortality rate?

>65 years

 

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3

What are the major categories of causes of meningitis?

Viral

Bacterial

Other (eg. TB)

Non infectious 

 

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4

What is the most common casue of meningitis?

Viral

Usually enterovirus

5

Even though viral meningitis is more common than bacterial meningitis, why is bacterial meningitis more worrying?

Viral meningitis does not cause sequelae, whereas bacterial meningitis does

Bacterial meningitis is more harmful, viral is self-limiting

6

What is aspetic meningitis?

Any form of meningitis that is not caused by bacteria

7

Which three bacteria are the commonest causes of meningitis?

H.influenza

N.meningitidis

S.pneumoniae

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8

Which of the bacterial causes of meningitis is the biggest killer?

In Africa, H.influenza A

9

Why are H.influenza, N. meningitidis and S.pneumoniae the commonest causes of bacterial meningitis?

These bacteria are best at evading the immune system 

Encapsulated with polysaccharide capsule > evade phagocytosis and complement activation

10

At less than three months of age, which additional causes of meningitis are infants susceptible to?

Those acquired in the birth canal

Group B strep, Listeria and E.coli

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11

Describe the host and bug factors that determine the likelihoods of infection?

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12

Describe how pathogens are able to penetrate defences and cause CNS infection?

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13

What are the major clinical features of meningitis?

Non-specific: fever, vomiting/nausea, headache, irritable and stop feeding (children)

More specific: stiff neck, altered mental state, bulging fontanelle, photophobia, seizures

 

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14

What are the major signs and symptoms of bacterial meningitis?

Fever

Vomiting

Stiff neck

Photophobia

Difficult to wake

Confused

Non-blanching rash

Seizures 

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15

What are the signs and symptoms of meningococcal septicaemia?

Non-blanching rash plus:

Fever

Vomiting

Lethargy

Muscle ache/joint apin

Cold extremities

Leg pain

Pale/mottled skin

Breathlessness

Confusion

Difficult to wake 

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16

Which investigations are usually carried out to diagnose meningitis?

CSF

Skin scraping

?Blood

?Neuroimaging

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17

Why don't blood samples provide a definitive diagnosis for meningitis?

May be changes in blood present that are not specific to meningitis

18

What are the normal values for CSF?

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19

Why can CSF values be unreliable whej diagnosing menigitis?

CSF values differ with age, and meningitis is predominately a paediatric disease

20

 Describe the CSF values for viral, bacterial and tuberculous meningitis?

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21

Describe viral, bacterial and tuberculous meningitis in terms of protein and white cell count in the CSF?

Viral: normal-high protein, normal-high white cells

Bacterial: high protein, very high white cells

Tuberculous: very high protein, high white cells

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22

What are the major contraindications for a lumbar puncture?

Raised ICP

Shock

Extensive purpura

Unstable convulsions

Coagulation abnormalities

Loacl superficial infection

Respiratory insufficiency

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23

Is CSF that is normal in appearrance necessarily normal?

No

Need large cell change to change appearance of CSF

24

Why is delay in CSF analysis a problem?

CSF cell count rapidly declines due to cell lysis

Unreliable if not measured immediately 

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25

What is the problem in using CSF values to diagnose meningitis?

Some bacterial patients will present like viral patients, and vice versa 

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26

What is the treatment for meningitis?

Resuscitation/life support

Fluids

Antibiotics

Steroids 

27

Which antibiotics are used to treat meningitis?

Intravenous 3rd generation cephalosporin

For paediatrics, add those that target the ones from the birth canal

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28

What is the most common complication of bacterial meningitis?

Hearing loss

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29

How is encephalitis treated?

Acyclovir

30

What is encephalitis?

Inflammation of the brain

31

What is the most common cause of encephalitis?

Almost always viral: HSV

32

Describe the conscious state in meningitis vs encephalitis?

Meningitis: normal consciousness

Encephalitis: altered conscious state

33

Describe how meningitis can be prevented?

Conjugate vaccines