NEURO 221 Meningitis

Question 1

What 4 routes can microbes enter the CNS via?

Answer 1

1) blood stream
2) direct implantation - trauma
3) local extension - from teeth, sinuses and ears
4) via the PNS e.g. rabie

Question 2

What cells make up the BBB?

Answer 2

brain microvascular endothelial cells surrounded by astrocyte projections

Question 3

What ways can a microbe enter the CNS if going via the blood stream?

Answer 3

Either at the BBB in the brain parenchyma

Or via the choroid plexus

Question 4

What is the choroid plexus in the brain?

Answer 4

plexus lining the ventricles containing ependymal cells that produce CSF

Question 5

Why is it easier to cross the BBB at the choroid plexus?

Answer 5

There are weaker tight junctions here (increased paracellular flux) and a fast rate of uptake/endocytosis (transcellular flux)

Question 6

What is a brain abscess?

Answer 6

A focal infection of the brain parenchyma usually due to bacteria

Question 7

What are the common microbes causing a brain abscess and what are the associations?

Answer 7

Associated with immunosuppresion
Acute abscess: mixed bacterial picture from oropharynx (streptococcus anginosus and bacteroides)
Chronic: TB, syphillus, Lymes disease. Fungal, parasitic e.g. toxoplasmosis

Question 8

What organism causes syphillus?

Answer 8

Treponema pallidum

Question 9

What organism causes lyme disease?

Answer 9

Borrelia burgdorefri

Question 10

What is meningitis?

Answer 10

Inflammation of the lining of the brain due to infection

100% fatal in bacterial infections if not treated

Question 11

What is the most common organism in meningitis to affect the age group:

Answer 11

Group B strep

Question 12

What is the most common organism in meningitis to affect the age group: >3mth

Answer 12

Streptococcus pneumoniae (45%)
N. Meningitidis (34%)

Question 13

What is the most common organism in meningitis to affect the age group: >10years

Answer 13

N. meningitidis

Question 14

What are the clinical features of meningism?

Answer 14

Headache, neck stiffness and photophobia

also: fever, N&V and general malaise

Question 15

What is a petechial non-blanching rash a sign of in meningitis?

Answer 15

bacteraemia

Question 16

What is brudzinskis sign?

Answer 16

neck rigidity - involuntary flexion of the hips when the neck is flexed

sign of meningitis

Question 17

What is kernigs sign?

Answer 17

pain and resistance on passive knee extension with full hip flexion

sign of meningitis

Question 18

What are the common causes of viral meningitis?

Answer 18

> 85% is enteroviruses

some echoviruses, cocksackie A&B and poliovirus

Question 19

What is the CSF profile of a bacterial infection?

Answer 19

turbid, increased neutrophils, increased protein, low or absent glucose

Question 20

What is a gram +ve cause of meningitis likely to be?

Answer 20

strep pneumonia

Question 21

What is a gram -ve cause of meningitis likely to be?

Answer 21

neisseria meningitidis

Question 22

What is a normal CSF profile?

Answer 22

clear, soem neutrophils and lymphoctues, 150-450mg/L protein, some glucose

Question 23

What is a viral CSF infection profile?

Answer 23

clear, increased lymphocytes, normal protein and glucose

Question 24

What stain would you use to look for a fungal infection in CSF?

Answer 24

Indian ink

Question 25

What stain would you use to look for a mycobacterial infection in CSF?

Answer 25

AFB

Question 26

When is a lumbar puncture contraindicated?

Answer 26

if suspected raised ICP, local skin infection

Question 27

How do you manage a suspected case of meningitis?

Answer 27

Immediate care!

1st contact: 999 and IM penicillin/ cefotaxime in allergy

Question 28

What antibiotics should be given to an infant

Answer 28

Ampicillin + aminoglycoside/cefotaxime

Question 29

What antibiotics should be given to an adult with meningitis?

Answer 29

cefatriaxone/cefotaxime

Question 30

What extra drug can be given to adults with their abx and what is the benefit -in meningitis?

Answer 30

Corticosteroids have been shown to reduce morbiditiy and mortality and long term neurological sequelae - no benefit in children

Question 31

What prophylaxis is given to direct contacts of those with meningitis?

Answer 31

rifampicin/ciprofloxacin

isnt treatment but erradicates the possible source!

Question 32

What is encephalitis?

Answer 32

acute inflammation of the brain parenchyma -often not pure but mixed as meningo-encephalitis

Question 33

What is the most common cause of encephalitis in the UK? What is it characterised by?

Answer 33

herpes simplex 1 - extensive necrosis of the temporal lobes