CNS Infections - Cellular Pathogens Flashcards Preview

MD1 Neuroscience > CNS Infections - Cellular Pathogens > Flashcards

Flashcards in CNS Infections - Cellular Pathogens Deck (60):
1

What is meningitis?

Inflammation of meninges

2

What is encephalitis?

Inflammation of brain

3

What is myelitis?

Inflammation of spinal cord

4

What is neuritis?

Inflammation of nerves

5

What is a brain abscess?

Pus in brain

6

What is a subdural empyema?

Pus in subdural space

7

What is an epidural abscess?

Pus in epidural space

8

Where are most cases of bacterial meningitis found?

96% in less developed countries

9

What is the mortality rate of bacterial meningitis globally?

50%

10

How many people have neurological sequalae after bacterial meningitis?

Half of survivors

11

Who is meningococcal disease most common in?

Children under age of 5

12

How does the likelihood of death from bacterial meningitis change over different age groups?

More likely as you get older

13

What are the causes of meningitis?

Culture positive
- Bacteria
Culture negative
- Bacteria
- Viruses
- Other

14

What is aseptic meningitis?

Culture negative
- Didn't grow bacteria
- Caused by something else

15

What is the most common cause of meningitis?

Viruses

16

What are the most common viral causes of meningitis?

Enteroviruses
- Coxsackie
- Echo

17

What are other infectious causes of meningitis?

TB
Fungus
Parasites
Syphilis
Lyme

18

What are some non-infectious causes of meningitis?

Malignancy
Drugs
- NSAIDs
- Antibiotics
- IV Ig
Inflammatory conditions
- Sarcoidosis
- Connective tissue disorders
- Lupus
- Vasculitis

19

Does viral meningitis usually need treatment? Why?

Doesn't usually need treatment because
- Self-limiting
- Don't get neurological sequelae

20

What are the most common causes of bacterial meningitis?

Neisseria meningitidis
Streptococcus pneumoniae
Haemophilus influenzae

21

Who gets infected with the three most common causes of bacterial meningitis?

Infants
Children
Adults

22

What are the most common types of N meningitidis in Australia?

B and C

23

Which type of N meningitidis is the most common killer of people and especially children worldwide?

A

24

Which type of H influenzae is most common in Australia?

Type b

25

Where are the three most common causes of bacterial meningitis usually found?

In nasopharynx

26

Which bacteria additionally cause bacterial meningitis in neonates and infants under the age of three months?

E coli and other Gram negative rods
Group B Streptococcus
Listeria monocytogenes

27

Where are the bacteria that especially infect neonates and young infants found?

In birth canal of mother

28

Which bacteria don't usually cause bacterial meningitis?

Streptococcus pyogenes (group A)
Staphylococcus aureus

29

What are the host factors that predispose a person to bacterial meningitis?

Genetics
Young age
Recent respiratory infection
Neuroanatomical defects
Immunodeficiency

30

What are the pathogen factors that predispose a person to bacterial meningitis?

Polysaccharide capsule
Infecting dose
Competing commensals

31

What are the environmental factors that predispose a person to bacterial meningitis?

Overcrowding
Smoke exposure
Season
Attendance at daycare
Sharing food, drink, and dummies

32

What are the steps in the development of bacterial meningitis?

1. Colonisation of nasopharyngeal mucosa
2. Invasion of bloodstream > bacteraemia
3. Survival and multiplication > septicaemia
4. Crossing of BBB
5. Invasion of meninges and CNS
6. Increased permeability of BBB
7. Pleocytosis
8. Increased intracranial pressure
9. Release of pro-inflammatory cytokines
10. Neuronal injury

33

What causes neuronal injury in bacterial meningitis?

Immune response

34

What are the non-specific symptoms and signs of meningitis?

Fever
Vomiting/nausea
Headache

35

What are more specific signs of meningitis?

Stiff neck
Altered mental state
Photophobia
Seizures

36

What is meningococcal disease often associated with?

Petechial or purpuric rash

37

How do you test if a rash is purpuric?

Put glass against rash > doesn't blanch

38

What are the normal values of CSF?

Pressure: 60% blood

39

Do normal CSF values change with age?

Yes

40

What does the CSF look like with viral meningitis?

Increased WCC
Negative Gram stain
Increased protein
Normal glucose

41

What does the CSF look like with bacterial meningitis?

Raised pressure
Cloudy
Hugely increased WCC
Positive Gram stain
Increased protein
Decreased glucose

42

What does the CSF look like with TB meningitis?

Raised pressure
Cloudy
Increased WCC
ZN positive stain
Increased protein
Decreased glucose

43

When don't you perform a lumbar puncture?

Raised ICP
Shock
Spreading purpura
After convulsions
Coagulationk abnormalities
Infection at site of lumbar puncture

44

What happens to the CSF sample if it isn't sent off to the lab immediately?

Cells start to lyse > WCC and glucose rapidly decrease

45

Can normal CSF results exclude meningitis?

No

46

Does pre-treatment with antibiotics change the WCC in CSF?

No

47

What is the treatment for bacterial meningitis?

Resuscitation/life support
Fluids
Antibiotics
Steroids
Contact prophylaxis

48

What are the antibiotics used for the treatment of bacterial meningitis?

IV 3rd generation cephalosporin
- Eg: cefotaxime/ceftriaxone
For neonates and infants under 3 months, add
- IV penicillin
- IV gentamicin

49

Why is the family of the patient also treated?

Because family at increased risk of infection, especially if bacteria N meningitidis

50

What antibiotic is given to contacts for prophylaxis?

Rifampicin

51

Which bacteria is associated with the worst complications?

Streptococcus pneumoniae

52

What is the most common neurological sequelae of bacterial meningitis?

Hearing loss

53

Why are steroids used in the treatment of bacterial meningitis?

Suppress immune response that causes damage

54

What is the state of consciousness in a person with meningitis?

Normal

55

What are the causes of encephalitis?

Almost always viral

56

What is the most common cause of viral encephalitis?

HSV

57

What are the symptoms of encephalitis?

Fever
Headache
Altered conscious state
+/- convulsions

58

What is added to the treatment if encephalitis is suspected?

Acyclovir

59

Why is acyclovir added to treatment of bacterial meningitis if encephalitis is suspected?

People can have meningoencephalitis

60

Which types of bacteria that cause meningitis are we vaccinated against?

H influenzae type b
S pneumoniae
N meningitidis A - given to travellers only
N meningitidis B - not on schedule, but available - very expensive
N meningitidis C

Decks in MD1 Neuroscience Class (55):