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Flashcards in CNS infections Deck (85):
1

what is meningitis inflammation of

all the meninges

2

why is time important in CNS infections

to save neural tissue
untreated infection may cause:
-brain herniation and death
-cord compression and necrosis (paralysis)

3

what is encephalitis

global infection of the brain parenchyma often caused by viruses

4

what is meningoencephalitis

inflammatory process (most often caused by viral infection), involving both the brain and meninges

5

what is encephalomyelitis

inflammation of the brain and spinal cord

6

what is neuritis

inflammation of one or more nerves

7

what are the types of menigitis

acute pyogenic (bacterial)
acute aseptic (viral)
acute focal suppurative infection (brain abscess, subdural and extradural empyema)
chronic bacterial infection (TB)

8

what is encephalopathy

any disease or disoder that affects the brain

9

what are the features of pyogenic meningitis

have a thich layer of suppurative exudate covering the leptomeninges over the surface of the brain
exudate in basal and convexity surface

10

what is seen microscopically in pyogenic meningitis

neutrophils in the subarachnoid space- lots of neutrophils in lumbar puncture= bacterial meningitis

11

do you get lots of neutrophils in CSF in a viral meningitis

no

12

what bacteria commonly cause bacterial meningitis

pneumococcus (strep pneumoniae)
meningococcus
haemophilus influenzae

listeria if >60 or immunocompressed

13

what is the treatment for bacterial meningitis

ceftriaxone IV
(if penicillin allergy chloramphenicol)
+
dexamethasone (IV) start with or just before abx

if listeria cover required add in amoxicillin IV (or co-trimoxazole if p allergic)

if recent travel ass in vancomycin IV for pneumococcal resistance

14

why should you make sure someone is allergic to penicillin before giving chloramphenicol

as v nasty drug - grey baby

15

what type of bacteria is strep pneumoniae

gram +ve cocci

16

what type of bacteria is listeria monocytogenes

gram +ve rod

17

what type of bacteria is haemophilis influenza

gram -ve bacillus

18

what causes viral meningitis

enteroviruses (echo virus)
herpes simplex (will have coldsores)
varicellar zoster virus


(in immunosuppressed EBV and CMV)

19

how is viral menigitis diagnosed

viral stool culture
throat swab
CSF PCR (will have only a few lymphocytes)

20

what is the treatment for viral meningitis

initially same as bacterial

supportive- e.g. vomiting give anti emetic

21

what should you not delay in suspected encephalitis

lumbar puncture (unless they have had seizures)

22

what Tx for viral encephalitis

IV aciclovir
LP after 14 days, HSV PCR weekly until negative

23

what are the clinical features of encephalitis

insidious onset
meningismus (features of meningitis without inflammation of the meninges)

cerebral cortex is diffusely involved:
mental changes
confusion
stupor
coma
seizures
partial paralysis
speech and memory symptoms
pychosis
focal or diffuse neurological changes

24

what are the clinical features of meningoencephalitis

features of encephalitis but with alos:
-headache
-fever
-neck stiffness

25

what viruses commonly causes viral encephalitis

herpes simplex

26

what investigations for encephalitis

LP, EEG, MRI

27

what are the symptoms of meningitis

headache
vomiting
pyrexia
neck stiffness
photophobia
lethargy
confusion
rash (non blanching)
muscle pain

28

what causes bacterial meningitis in neonates

listerior, group B strep, e coli

29

what causes bacterial meningitis in children

h influenza (vaccinate against this)

30

what causes bacterial meningitis in ages 10-21

neisseria meningitidis

31

what causes bacterial meningitis in ages over 21

strep pneumoniae , neisseria meningitidis

32

what causes bacterial meningitis in overs 65s

streptococcus pneumoniae, listeria

33

what causes bacterial meningitis in the immunocompromised

S. pneumoniae, N. meningitidis, listeria, aerobic GNR

34

what causes bacterial meningitis in basilar skull fractures

s. pneumoniae, h. influenzae, beta hemolytic strep group A

35

what causes bacterial meningitis in head trauma/ post op

s. aureus, s epidermis, aerobic GNR

36

what causes bacterial meningitis in a CSF shunt

s. epidermis, S aureus, aerobic GNR, p. acnes

37

what are the possible complications of meningitis

as limb loss, deafness, blindness, cerebral palsy, quadriplegia and severe mental impairment

Purulence
Exudate around nerves (III, VI cranial nerves particularly vulnerable)

invasion and abscesses

cerebral oedema

ventriculitis/ hydrocephalus

38

what are the pathogeneses of bacterial meningitis

-nasopharyngeal colonisation (most common)
-direct (sinusitis, mastoiditis, brain abscess, skull defects/ fracture
-from remote foci of infection (endocarditis, pneumonia, UTI)

39

what do you analyse in CSF from a lumbar puncture

Tube 1. Hematology: cell count, differential
Tube 2. Microbiology: gram stain, cultures
Tube 3. Chemistry: glucose (will be low in meningitis as bacteria eating it), protein
Tube 4. Hematology: cell count, differential

opening pressure
lactate

40

what precautions must be made in lumbar punctures

be careful of raised ICP (dont do)
treat with antibiotics first in suspected bacterial infection

41

what CSF results are 99% predictive of bacterial meningitis

high WBC count
higher neutrophils
high protien
low glucose
low glucose (CSF/serum)

42

what are the typical CSF findings in viral meningitis

lymphocytes
protein normal/ slightly high
glucose usually normal
gram stain will be negative

43

what will the gram stain be in TB CSF analysis

may be pos or negative

44

what causes the symptoms in neisseria meningitis

endotoxin

45

who usually gets neisseria meningitis

young children

46

what does the rash look like in meningococcal infection

non blanching purpura that look like coalesced bruises

47

what does H influenza require for growth

blood factors

48

what is the most common cause of meningitis in children under 4

h influenzae

49

where is strep pneumoniae usually found- why is this important

nasopharynx

Hospitalized patients, patients with CSF skull fractures, diabetics/ alcoholics and young children are most susceptible to S. pneumoniae meningitis.

50

what tx for cryptococcus meningitis

will have very high ICP so give serial LPs and anti fungals (IV amphotericin A/ flucytosine, fluconazole)

51

who gets cryptococcus

HIV patients

52

what is the most common meningitis in immunocompromised

listeria

53

what are the features of cryptococcal meningitis

fungal
mainly in HIV disease
low CD4
disseminated infection
aseptic CSF

54

who gets listeria meningitis infections

neonates
>55s
immunosuprpessed (esp malignancy)

55

what antibiotic for listeria

IV amoxicillin (or ampicillin)

56

what are the features of tuberculous meningitis

reactivation, elderly
often non specific illness
previous TB on CXR
hard to diagnose- poor yield on culture

57

tx for TB meningitis

Isoniazid + rifampicin key (add pyrazinamide + ethambutol)

58

why can bacterial meningitis be culture negative

10-15% are anyway
pre LB use of oral antibiotics can lower culture

59

what other than bacterial meningitis can a neutrophilic & low glucose CSF mena

early viral
leakage of abscess into ventricle
TB

chemical meningitis
behcet syndrome
drug induced

60

what is aspetic meningitis

non pyogenic bacterial meningitis:
spinal fluid that contains
-low WBC
-minimally elevated protein
-normal glucose

can be lots of things other than viral meningitis

61

what are the (treatable) causes of aseptic meningitis/ encephalitis

Infectious:
HSV 1 and 2
Syphilis
Listeria (occasionally)
Tuberculosis
Cryptococcus
Leptospirosis
Cerebral malaria
African tick typhus
Lyme disease

Non-Infectious:
Carcinomatous
Sarcoidosis
Vasculitis
Dural venous sinus thrombosis
Migraine
Drug
Co-trimoxazole
IVIG
NSAIDS

62

what are the contact prophylaxis regimes for meningitis

500 mg ciprofloxacin orally as a single dose for adults and children aged more than 12 years

600 mg rifampicin orally 12-hourly for four doses (adults and children over 12 years)

63

should you involve public health about meningitis

yes- all suspected cases

64

what vaccines protect against meningitis

travel vaccinations (neisseria)
HiB vaccine
pneumococcal vaccines

65

which space are samples obtained from in an LP

subarachnoid space

66

what are normal CSF WBC and RBC counts

white 0-5
red 0

67

what are the expected ratios for protein and glucose in CSF

glucose 0.6 (should be 2/3rds of blood glucose)
protein 150-450:1

68

proportionally more neutrophils (aka polymorphs) in CSF= ?

bacterial infection

69

proportionally more lymphocytes in CSF= ?

viral/ fungal infection

70

what is petechea

non blanching rash, meningitis

71

what are the rules for CTs and LPs

NEVER DO LP WITHOUT DOING CT AS MIGHT HAVE RAISED ICP- cause brain to herniate = coning (when cerebellum goes through foramen magnum)

unless
in suspected meningitis if patient has no focal deficit, is not immunocompromised, no skull #, has had no seizures,no Hx of CNS disease, no papilloedema, normal conscious level then do LP ASAP and start antibiotics

72

gram -ve cocci meningitis= ?

meningococcus meningitis (caused by neisseria)

73

what drug for chemoprophylaxis for bacterial meningitis

ciprofloxacin

74

what is the abx treatment for a brain abscess

IV ceftriaxone
IV metronidazole

add flucloxacillin in staph suspected
IV vancomycin if pen allergic/ MRSA suspected

for 4 weeks minimum

75

what other tests should be done in viral meningitisi

throat swap
stool sample
HIV test

76

what CNS infection causes oedema in the temporal loves

herpes simplex encephalitis

77

what test to confirm herpes simplex encephalitis

PCR from LP

78

what 3 tests do you prioritise in meningitis

LP
CT
blood culture

79

gram +ve diplococci meningitis= ?

pneumococcus

80

where can an brain abscess originate from

mastoiditis
sinusitis
orbital cellulitis

81

what organisms can cause brain abscesses

streptococci, bacteriodes, staphylococci, anaerobes, colliforms

82

why do you give ceftriaxone and not penicillin for meninigitis

as lasts longer in CSF

83

when do you delay an LP in meningitis

signs of severe sepsis
cardiac/ resp compromise
rapidly evolving rash
significant bleeding risk
signs suggesting shift of brain compartments (do CT)
- focal neuro signs
- papilloedema
- seizures that are continuous/ uncontrolled
- GCS = 12

84

buzzworrds: summer/ autumn time, GI symptoms

enterovirus viral meningitis

85

what is the key symptom in encephalitis

confusion