CNS infections

Question 1

Define Meningitis

Answer 1

inflammation of the meninges

Question 2

Define encephalitis

Answer 2

inflammation of the brain

Question 3

Define myelitis

Answer 3

inflammation of the spinal cord

Question 4

Deine neuritis

Answer 4

inflammation of the peripheral nerves

Question 5

Name 4 routes of meningitis infection

Answer 5

Blood borne
Parameningeal supparation ( otis media, sinisitis
Direct spread through defect in the dura (surgery or trauma)
Direct spread though cribiform plate (rare)

Question 6

What characteristics of the CSF make it unusual to treat

Answer 6

Low protein/complement
Low IgG
no lymphatics
BBB

Question 7

How does bacteria get into the blood stream from the naspharynx

Answer 7

IgA protease
pili
endocytosis
separate tight junctions

Question 8

In the blood how does the bacteria avoid attack

Answer 8

Capsules resistlysis/phagocytosis

Question 9

In the CSF how does bacteria avoid the immune system

Answer 9

no ig C3/4 or professional phagocytes

Question 10

Once in the CSF what does the presence of bacteria trigger

Answer 10

Mononuclear and glial cells
migration of neutrophils- release of cyto-toxic oxygen metabolites
cerebral capillary endothelium so allow entry of plasme proteins = oedema

Question 11

What are meningism symptoms

Answer 11

Global severe headache
neck and back stiffness
nausea and vomiting
photophobia

Question 12

What are some physical signs

Answer 12

Fever ( also can be low )

rash-purpuric/petechial in menginococcal but also streptococcal, hib spp and enterovrius

Question 13

What is the constellation of symptoms in bacterial meningitis

Answer 13

97% fever
82% meningism
66% impaired consiousness
52% rash
30% seizures

Question 14

For an adult what symptoms suggest they have a more than 50% chance of death or permanent damage

Answer 14

Hypotension
serizures
and altered consiousnes

Question 15

What signs of bacterial meningitis are specific to children

Answer 15

Flaccid or later opisthotonus
bulging fontanelle
strange cry
convulsions

Question 16

What is the most rapid diagnostic test for bacterial meningitis

Answer 16

Lumbar puncture but there is a risk of herniation with raised ICP

Question 17

When is a CT scan indicated

Answer 17

When the diagnosis is in doubt
with focal abnormalities
with coma or seizures

Question 18

Name 6 causes of lymphocytic CSF

Answer 18

TB
partially treated bacterial infection
intracranial abcesses
Leptospirosis
Lyme borreliosis
Viral meningo-enceohalitis
syphillis
lymphocytic leukaemias

Question 19

What tests can be done on CSF for menigitis

Answer 19

Gram stain
Zn
Agglutination
PCR

Question 20

Name 6 organisms that cause bacterial meningitis

Answer 20

Neisseria meningitidis
streptococcus pneumoniae
Heamophilus influenzae type B 
group B streptococcus
e.coli
listeria monocytogenes

Question 21

Which bacteria are most likely to affect children and young adults

Answer 21

n. meningitidis

Question 22

Which bacteria are likely to affect neonates

Answer 22

Group B streptococcus
e.coli
Listeria monocytogenes

Question 23

Which bacteria is it unlikely to be now because of vaccination

Answer 23

Heamophilus influenzae type B

Question 24

Which bacteria are you worried about in the elderly and children under 2

Answer 24

streptococcus pneumoniae

Question 25

What are the predisposing factors or pnuemococcal meningitis

Answer 25

Alcohol, diabetes, immunocompromised, hyposplenism, myeloma

Question 26

What are characteristic signs of pneumococcal meningitis

Answer 26

Pneumonia +/- otis media in 50% | neurological signs, seizures and imparied consiousness

Question 27

What gram stain is listeriosis

Answer 27

negative

Question 28

What characterises listeriosis

Answer 28

Effets brainstem, ataxia and movement disorders

Question 29

What are the complications of meningitis

Answer 29

``` Death subdural collection cerebral vein thrombosis hydrocephallus deafness convulsions visual/motor/sensory deficits ```

Question 30

What are the management strategies for meningitis

Answer 30

``` Antibiotics oxygen decrease ICP prevention of hypoglycaemia and hyponatreamia anticonvulsants ```

Question 31

For which meningitis are steroids indicated

Answer 31

Hib species

Question 32

When is chemoprophylaxis indicated

Answer 32

Hib and meningococcal for kissing or household contacts

Question 33

What can myelitis cause

Answer 33

transverse- acute transection of the spinal cord

Question 34

What are some causes of myelitis

Answer 34

vasculitis of anterior spinal artery- primary infection=VZV TB Syphilis post infection=measels mumps rubella direct invasion of cord= VZV borrelia HTVL-1

Question 35

What are some symptoms of myelitis

Answer 35

Flaccid paralysis, sensory loss

Question 36

What are some symptoms of encehalitis

Answer 36

``` irritability altered personality drowsiness cerebral/brainstem failure ataxia excessive brisk tendon reflexes sluggish pupil reflexes signs of brain swelling ```

Question 37

What causes primary encephalomyeltis and what is their entry to the body

Answer 37

HSV-1 mucosa enteroviruses gi tract listeria gi tract measels and mumps resp tract

Question 38

What things cause encephalomyelitis post infection

Answer 38

Chicken pox flu A+B measels

Question 39

How do you treat HS encephalitis

Answer 39

aciclovir

Question 40

How do you treat most viral mengintis

Answer 40

self-limting, so only supportive treatment

Question 41

Comparing bacterial, viral and TB mengitis what is the difference in a) predominant cell b) cell count c) protein d) glucose

Answer 41

a) bacterial =polymorphs and viral and tb = lymphocytes b) high cell count, slight to mod, mod to high c) high, normal/raised, high d) low, normal/low, low

Question 42

Other than cellular picture of CSF what indicates bacterial rather than viral meningitis

Answer 42

``` systemic inflammation ( CRP marker) rash ```

Question 43

What is the commonest cause of viral meningitis

Answer 43

Enterovirus

Question 44

What antibiotics are mostly used for bacterial menginitis a) in adults b) neonates

Answer 44

a) Cefriaxone + amoxycilin if listeria? | b) benzylpenicillin and gentamicin