CNS infections

Question 1

presentation of meningitis?

Answer 1

meningism:

• HA
• photophobia
• neck stiffness

Question 2

how does bacterial meningitis usually arise?

Answer 2

local spread from the sinuses, the nasopharynx or the ear

Question 3

most common causative pathogen in bacterial meningitis in

1) neonates
2) infants
3) children/ adolescents
4) adults
5) elderly

Answer 3

1) group B strep
2) N.meningitides
3) N.meningitides
4) strep. pneumonie
5) strep. pneumonie

Question 4

most likely causative pathogen in bacterial meningitis in

1) fractured cribiform plate
2) neurosurgery/ head trauma
3) pregnancy

Answer 4

1) strep pneumonie
2) staph aureus and epidermidis
3) listeria monocytogenes

Question 5

what bacterial cause of meningitis is this:

1) gram negative diplococcus
2) gram positive coccus
3) gram negative coccobacillus
4) beta heamolytic gram positive flagellated rod

Answer 5

1) N. meningitides
2) strep. pneumoniae/ group B strep
3) haemophilus influenza B
4) L. monocytogenes

Question 6

Bacterial meningitis clinical features?

Answer 6

meningism: HA, photophobia, neck stiffness
fever
Kernigs sign (resists knee extension when hip flexed)
Brudzinksi’s sign (neck flexion causes hip and knee flexion)
Tumbler test +ve

NB: viral is same but fever may be less pronounced

Question 7

what type of bacterial meningitis is the tumbler test most commonly +ve in?

Answer 7

meningococcal septicaemia

Question 8

what Ix is also done pre-LP in meningitis?

Answer 8

CT: to rule out increased ICP. Always done pre-LP to prevent coning

Question 9

treatment of community acquired meningitis?

1) normal circumstances
2) if listeria is suspected (>55/ neonate/ immunosuppressed)

Answer 9

1) IV ceftriaxone + dexamethasone with first dose

2) add amoxicillin for cover

Question 10

why is dexamethasone given in community acquired meningitis?

Answer 10

reduce long term complications, esp deafness

Question 11

prophylactic therapy for those in close contact with the meningitis patient?

Answer 11

ciprofloxacin

rifampicin 2nd line

Question 12

T/F: viral meningitis is a form of aseptic meningitis

Answer 12

true (culture negative)

Question 13

common causes of viral meningitis?

Answer 13

commonly enteroviruses (e.g. echovirus)

more severe infection: HSV (can progress to encephalitis)

Question 14

Ix in viral meningitis?

Answer 14

LP: clear, raised lymphocytes, normal protein, low/ normal glucose

Question 15

treatment of viral meningitis?

Answer 15

normally self limiting

IV acyclovir if severe

Question 16

how does presentation of TB meningitis vary from typical bacterial meningitis?

Answer 16

features of meningism not always present, can present with more general features e.g. headache and fever

Question 17

characteristic CSF findings in TB meningitis?

Answer 17

clear and culture negative CSF, lymphocytosis, high protein, low glucose, fibrin webs

Question 18

what is encephalitis?

Answer 18

inflammation of the brain parenchyma commonly caused by viral infection

Question 19

most common cause of encephalitis?

Answer 19

HSV - tends to spread through olfactory nerve/ from reactivation of the trigeminal root ganglion

Question 20

clinical features of encephalitis?

Answer 20

acute onset HA, fever, altered consciousness, focal neuro deficit (aphasia, hemiplegia, visual field defect), meningism

Question 21

in encephalitis, certain features suggest a particular aetiology

1) seizures with focal neurological deficits (aphasia)
2) parotitis in an unvaccinated patient
3) skin lesions/ vesicles in a dermatomal pattern

Answer 21

1) HSV
2) mumps
3) VZV

Question 22

Ix in encephalitis?

Answer 22

CT: cerebral oedema
MRI: oedema in temporal lobes (HSV)
CSF PCR

Question 23

treatment of encephalitis?

Answer 23

IV acyclovir

Question 24

Subacute sclerosing panencephalitis:
An uncommon but serious sequalae of the ____ virus where the onset can be as
late as ____ after the initial infection. It tends to present how?

Answer 24

measles
years
change in personality, cognitive decline, myoclonus: reflecting the diffuse cortical involvement

Question 25

CSF findings in 
1) bacterial meningitis
2) viral menigitis
3) TB meningitis
(appearance, opening pressure, cells present, protein, glucose)

Answer 25

1) cloudy, elevated opening pressure, neutrophils, high protein, low glucose
2) clear, normal opening pressure, lymphocytes, high protein, normal glucose
3) opaque (forms fibrin web if left to settle), elevated opening pressure, lymphocytes, high protein, low glucose

Question 26

CSF findings in

1) MS
2) GBS
3) Alzheimer’s
4) subarachnoid haemorrhage

Answer 26

1) oligoclonal bands
2) high protein
3) increased phosphorylated tau protein, decreased B-amyloid
4) xanthochromia

Question 27

CSF findings in

1) creutzfeldt-jakob disease
2) idiopathic intracranial hypertension
3) narcolepsy

Answer 27

1) elevated 14-3-3 protein
2) high opening pressure
3) low/ undetectable levels of CSF orexin/ hypocretin

Question 28

diagnosis of Subacute sclerosing panencephalitis:?

Answer 28

often clinical
MRI can characterise involvement
CSF may show raised IgG anti-measles Abs (chronic infection)