CNS infections

Question 1

histological appearance of bacterial meningitis

Answer 1

neutrophils in subarachnoid space

Question 2

common viruses which cause meningitis

Answer 2

enteroviruses (eg ECHO)
herpes simplex
varicella zoster
paramyxovirus

Question 3

how to diagnose viral meningitis

Answer 3

viral stool culture
throat swab
CSF PCR

Question 4

treatment of viral meningitis

Answer 4

Supportive therapy - it is self-limiting

Question 5

if viral meningitis, what else should be tested for

Answer 5

HIV

if HSV, test for other sexually transmitted diseases

Question 6

encephalitis is usually bacterial/viral

Answer 6

viral - HSV1+2 most common

Question 7

clinical features of encephalitis

Answer 7

meningism 
odd 
behaviour/confusion
low GCS/coma
fever 
headache 
focal neurological symptoms/seizures
PRECEDED BY SYMTPOMS OF INFECTION

Question 8

investigations for encephalitis

Answer 8

blood cultures (including toxoplasma IgM titre and malaria film)
lumbar puncture (increased protein and lymphocytes, decreased glucose, send for PCR)
EEG
MRI - inflamed portion of temporal lobe

Question 9

Start treatment immediately/after lab results in encephalitis

Answer 9

immediately

Question 10

treatment for viral encephalitis

Answer 10

If herpes/varicella, IV acyclovir for 14 days then repeat lumbar puncture
continue until PCR is negative

Question 11

common bacterial organisms in neonates

Answer 11

listeria
group B strep
Ecoli

Question 12

common bacterial organism in children

Answer 12

H influenza

Question 13

common bacterial organism age 10-21

Answer 13

Neisseria meningitidis

Question 14

common bacterial organism >21

Answer 14

strep pneumonia

can be Neisseria meningitides

Question 15

common bacterial in ?65

Answer 15

strep pneumonia

can be listeria

Question 16

bacterial organism if cell mediated immunity (e.g. neonatal, immunosuppressed, malignancy)

Answer 16

listeria monocytogenes
S. pneumoniae
N. Meningitidis
aerobic GNR

Question 17

bacterial organism if neurosurgery/head trauma/CSF shunt

Answer 17

S. Aureus
S. epidermidis
aerobic GNR

Question 18

bacterial organism if fracture of cribiform plate

Answer 18

strep pneumonia
H influenza
beta-haemolytic strep group A

Question 19

most common organisms causing meningitis

Answer 19

meningococcus (Neisseria meningitides)

pneumococcus (strep pneumoniae) - MOST COMMON

Question 20

where does Neisseria meningitides usually reside

Answer 20

throats of healthy carriers - gets to meninges through bloodstream

Question 21

what meningitis organisms have a prophylactic vaccination

Answer 21

Neisseria meningitides
H influenza
Strep pneumoniae

Question 22

clinical presentation of tuberculous meningitis

Answer 22

non-specific ill health with previous TB on CXR

Question 23

treatment for TB meningitis

Answer 23

isoniazid and rifampicin

add pyrazinamide and ethambutol later

Question 24

early clinical signs of bacterial meningitis

Answer 24

headache
leg pins
cold hands and feet
abnormal skin colour

Question 25

signs of meningism

Answer 25

neck stiffness photophobia Kernig's sign (pain and resistance on passive knee extension with hip fully flexed)

Question 26

late clinical features of bacterial meningitis

Answer 26

``` meningism decreased consciousness seizures/focal neurological signs petechial rash (non-blanching) pyrexia ```

Question 27

treatment should be started immediately/after culture results in meningitis

Answer 27

immediately

Question 28

immediate action in suspected bacterial meningitis

Answer 28

ceftriaxone IV and Dexamethasone IV immediately AFTER blood cultures are taken

Question 29

when is lumbar puncture contraindicated

Answer 29

suspected ICP uncorrected coagulopathy acute spinal cord trauma severe sepsis/rapidly evolving rash

Question 30

what antibiotic should be used if penicillin allergic

Answer 30

chloramphenicol IV + vancomycin IV

Question 31

what antibiotic should be added if listeria cover is required

Answer 31

amoxicillin/ampicillin IV

Question 32

if recent travel in last 6 months, what antibiotic should be added

Answer 32

vancomycin or rifampicin

Question 33

what organism should dexamethasone be continued for

Answer 33

pneumococcal

Question 34

what time of year is viral meningitis common

Answer 34

late summer/autumn

Question 35

later tests in meningitis

Answer 35

throat swab culture rash CT if papilloedema/focal neuro signs lumbar puncture if feasible

Question 36

Results of CSF culture in meningitis

Answer 36

neutrophils and protein increased | low glucose

Question 37

what does N meningitidis look like histologically

Answer 37

gram negative coffee bean shaped diplococci

Question 38

what does S pneumoniae look like histologically

Answer 38

gram positive lanceolate diplococci appearing in short chains

Question 39

H influenzae on gram stain

Answer 39

pleomorphic gram negative rods

Question 40

why might meningitis be 'culture negative

Answer 40

pre-lumbar puncture use of oral antibiotics for a different infection

Question 41

what empirical antibiotic if penicillin allergy and listeria cover required

Answer 41

co-trimoxazole

Question 42

when should steroids be avoided

Answer 42

post surgical meningitis severely immunocompromised meningoccal/septic shock hypersensitive to steroids

Question 43

what are the contact prophylaxis regimens for bacterial meningitis

Answer 43

600 mg rifampicin orally 12-hourly for 4 doses OR 500mg ciprofloxacin orally as a single dose

Question 44

consequences of untreated infection

Answer 44

brain herniation and death | cord compression and necrosis - permanent paralysis

Question 45

complications of meningitis

Answer 45

purulence - clusters at base of brain, exudate around nerves (3 and 6 particularly vulnerable) invasion - abscesses cerebral oedema ventriculitis/hydrocephalus