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Flashcards in Infections of Nervous System Deck (72):
1

what may untreated CNS infection cause?

brain herniation and death

cord compression and necrosis with subsequent permanent paralysis

2

what is bacterial meningitis?

infection of brain meninges

3

what are the two types of meningitis?

acute pyogenic (bacterial) meningitis

acute aseptic (viral) meningitis

4

what causes meningitis in neonates?

listeria
group B strep
E. coli

5

what causes meningitis in children?

H influenzae

6

what causes meningitis in ages 10-21?

neisseria meningitidis

7

what causes meningitis in ages >21?

strep pneumoniae > neisseria meningitidis

8

what causes meningitis in ages >65?

strep pneumoniae > listeria

9

what causes meningitis in those with decreased cell mediated immunity?

listeria monocytogenes

10

what causes meningitis in those with head trauma / post neurosurgery?

staphylococcus
gram negative bacilli

11

what causes meningitis in those with fracture of cribiform plate?

strep pneumoniae

12

what causes meningitis in those with CSF shunt?

staph epidermis
staph aureus
aerobic GNR
propionibacterium acnes

13

what is the three main ways bacterial meningitis can colonise?

nasopharyngeal colonisation

direct extension of bacteria (from parameningeal foci or across skull defects)

from remote foci of infection (endocarditis etc)

14

what is the pathology of bacterial meningitis?

thick layer of suppurative exudate which covers leptomeninges over surface of brain

also exudate in basal and convexity surface

15

what is present in subarachnoid space in bacterial meningitis?

neutrophils

16

what are the symptoms of bacterial meningitis?

fever
neck stiffness
change in mental state
headache
rash
papilloedema (3%)

17

what is gold standard for diagnosis of meningitis?

lumbar puncture - send 4 tubes away

18

in what cases would you give a CT before lumbar puncture?

immunocompromised
history of CNS disease
new onset seizure
papilloedema (raised ICP)
altered level of consciousness
focal neurological deficit

19

what additional investigations may you carry out in suspected bacterial meningitis?

blood cultures
FBC + coagulation screening
swab rash
throat swab = meningococci

20

what is given as empirical treatment before lumbar puncture in bacterial meningitis?

10 days of ceftriaxone IV 2g bd and dexamethasone IV 10mg

penicillin allergic = chloramphenicol IV 25mg

21

what is the treatment once meningococcus (neisseria meningitidis) confirmed?

ceftriaxone (5-7 days)
stop dexamethasone

22

what is given when pneumococcus confirmed?

ceftriaxone (10-14 days)
4 days dexamethasone

23

what is given if listeria suspected (if >60 or immunocompromised)?

amoxicillin IV 2g hourly
stop dexamethasone

allergic = co-trimoxazole IV 120mg

24

what is given when H influenzae confirmed?

10 days ceftriaxone
stop dexamethosone

25

what do you add to treatment if patient has recently travelled to places with penicillin resistant pneumococcal?

vancomycin IV or rifampicin IV / PO

26

when would a hospital admission be required for bacterial meningitis?

signs of meningeal irritation

impaired conscious level

petechial rash

febrile or unwell and have had a recent fit

any illness (especially headache) and are close contacts of patients with meningococcal infection, even if they have received a prophylactic antibiotic

27

what measures can be taken to try and prevent secondary cases of bacterial meningitis?

telephone reporting to public health

GPs informed to locate close contacts to implement chemoprophylaxis and vaccination

28

what are the 3 options which can be given as contact prophylaxis of bacterial meningitis?

rifampicin PO 12-hourly for four doses (adults and children >12 years)

ciprofloxacin PO single dose for adults and children >12 years

ceftriaxone IM single dose in adults, IV single dose in children under 12 years

29

what are side effects of rifampicin?

reduced efficacy of oral contraceptives

red colouration of urine

staining of contact lenses

30

what are the complications of bacterial meningitis?

purulence
invasion
cerebral oedema
ventriculitis / hydrocephalus

31

where does purulence occur when it is a complication of bacterial meningitis?

clusters at base of brain

convexities of rolandic and sylvian sulci

exudate around cranial nerves (esp III and VI)

32

how does invasion occur when it is complication of bacterial meningitis?

pia prevents meningitis becoming abscess

abscesses can cause secondary ventriculitis and hence meningitis

33

where is neisseria meningitidis usually found in healthy carriers?

throat

34

how does neisseria meningitidis probably gain access to the meninges?

blood stream

35

are the symptoms of neisseria meningitidis are usually due to exotoxin or endotoxin?

endotoxin

36

who does neisseria meningitidis most often cause disease in?

young children

37

to prevent epidemics of neisseria meningitidis in training camps, military recruits are vaccinated with what?

purified capsular polysaccharide

38

as well as meningitis, what else can meningococcal infection cause?

local - conjunctivitis, arthritis

meningitis with septicaemia

fulminant septicaemia

39

where is H influenzae normally found?

throat

40

what type of H influenzae is most common cause of meningitis in children under 4?

type b

41

where is strep pneumoniae commonly found?

throat

42

who is most susceptible to pneumococcal meningitis?

hospitalised patients
patients with CSF skull fractures
diabetics / alcoholics
young children

43

there is some evidence that pneumococcal meningitis is related to CNS devices such as what?

cochlear implants

44

does the conjugate vaccine for pneumococcal pneumonia also protect against pneumococcal meningitis in children?

yes

45

who does listeria monocytogenes meningitis usually occur in?

neonates
>55
immunosuppressed especially malignancy

46

what type of bacteria is listeria monocytogenes?

gram positive bacilli

47

what vaccination is available for neisseria meningitidis?

serogroups A and C (W135 and Y)

commonly used in travel vaccination

48

what vaccination is available for haemophilus influenzae meningitis?

HiB vaccine

49

what vaccination is available for streptococcus pneumoniae meningitis?

pneumococcal vaccines (polysaccharide and conjugate)

50

what is more common - bacterial or viral meningitis?

viral

51

when does viral meningitis most commonly occur?

late summer / autumn

52

what causes viral meningitis?

enteroviruses eg ECHO
other microbes and non-infectious causes

53

how is viral meningitis diagnosed?

viral stool culture
throat swab
CSF PCR

54

how is viral meningitis treated?

supportive - self limiting

55

what is aseptic meningitis?

this is a term used to mean non-pyogenic bacterial meningitis

56

what is the characteristics of the spinal fluid in aseptic meningitis?

low WBC
elevated protein
normal glucose

57

what causes aseptic meningitis?

infection
carcinomatous
sarcoidosis
vasculitis
dural venous sinus thrombosis
migraine
drugs - co-trimox, IVIG, NSAIDs

58

what infection must you not forget is a cause of aseptic meningitis?

HSV

59

what is encephalitis?

infection of brain parenchyma

60

what are the symptoms of encephalitis?

insidious onset
meningismus
stupor, coma
seizures, partial paralysis
confusion, psychosis
speech, memory symptoms
focal or diffuse neurological signs

61

what is most common virus which causes encephalitis?

HSV

62

how is encephalitis diagnosed?

lumbar puncture
EEG
MRI

63

how do you treat encephalitis?

pre-emptive acyclovir

64

what is tuberculosis meningitis?

meningitis caused by M tuberculosis

65

who does tuberculosis meningitis usually affect?

elderly as reactivation

66

what are symptoms and investigation results in tuberculosis meningitis?

often non-specific ill health
previous TB on CXR
poor yield from CSF

67

what is treatment of tuberculosis meningitis?

isoniazid + rifampicin key

add pyrazinamide + ethambutol

68

what is cryptococcal meningitis and who does it usually occur in?

fungal type of meningitis which usually occurs in those with HIV

69

what is the CD4+ value in cryptococcal meningitis?

<100

70

what are the symptoms of cryptococcal meningitis?

subtle neurological presentation
disseminated infection symptoms

71

what investigations should take place in cryptococcal meningitis?

CSF - aseptic

serum and CSF cryptococcal antigen

72

what is treatment for cryptococcal meningitis?

IV amphotericin B + flucytosine for 2 weeks

add fluconazole PO for 8 weeks