Lecture 18 - Meningitis

Question 1

Name some possible routes of infection for meningitis

Answer 1

> blood borne, parameningeal suppuration e.g. otitis media sinusitis
direct spread through defect in the dura (post surgery/ trauma)
direct spread via cribiform plate

Question 2

Name some complications of meningitis

Answer 2

death, subdural collection, cerebral vein thrombosis, hydocephalus, deafness (Hib) in kids, convulsions, visual/motor/ sensory deficit

Question 3

Name the common bacteria causing meningitis

Answer 3

neisseria meningitidis - children/young adults

streptococcus pneumoniae - elderly / young children

Question 4

which bacteria can be found in foods such as unpasturised cheese

Answer 4

listeria monocytogenes

Question 5

Why is bacteria in the CSF a greater concern than if bacteria was in the blood

Answer 5

no proteins ( low compliment )
low igG
no lymphatics
only lipophilic compounds through the blood brain barrier

Question 6

describe the inflammatory process associated with meningitis

Answer 6

1) endotoxin released by Gr -ves and lipotechoic of Gr +ves - trigger inflammatory cascade (TNF INL PAF NO)
2) neutrophils migrate to CSF and release o-
3) free rads damage vascular endothelium alter BBB permeability

Question 7

Symptoms of meningitis and physical signs

Answer 7

• headache, neck and back stiffness, nausea and vomiting, photophobia
• fever, petechial rash (usually meningococcal)
• kernigs sign (leg at right angles), brudzinskis sign (flexion neck causes leg flexion), neck stiffness (cant put head on chest)

Question 8

name some other conditions with similar symptoms of meningitis

Answer 8

UTI, dysentery, sub arachnoid haemorrhage, NSAIDs

Question 9

Name some symptoms of meningitis in infants

Answer 9

flaccid, bulging fontanelle (increased ICP), fever and vomiting, strange cry and convulsions

Question 10

What is the most rapid diagnostic test for meningitis? what does it show?

Answer 10

lumbar puncture, can distinguish between viral and bacterial

Question 11

What is the risk of a lumbar puncture in the diagnosis of meningitis?

Answer 11

herniation of brain! if raised intracranial pressure and longer history of symptoms (focal neurology and drowsy)

Question 12

When examining CSF whats distinctive about 1) bacterial meningitis 2) TB meningitis 3) viral meningitis

Answer 12

1) bacterial high polymorphs (neutrophils) and low glucose
2) TB high lymphocytes and low glucose
3) high lymphocytes

Question 13

What are the complications of menningococcal disease

Answer 13

• death 13% higher if sepsis 40%.
• necrotic lesions and reactive arthtiris (around purpura rash)
• serositis, neurological and access formation both RARE

complications alter with serogroup type

Question 14

Name the risk factors for poor outcomes with meningitis

Answer 14

• positive blood cultures
• sinusitis or otitis media
• old age
• low CSF (low white cell count)
• thrombocytopenia
• tachycardia
• absense of rash
• low GCS

Question 15

How would you manage meningitis (5)

Answer 15

• antibiotics
• oxygenation
• prevent hypoglycaemia and hyponatraemia
• anticonvulsants
• decreased ICP

Question 16

Name two things an antibiotic against meningitis needs to be

Answer 16

• bacteriacidal

- be able to penetrate the BB to CSF at non-toxic doses

Question 17

What helps CSF penetration

Answer 17

high lipid solubility, low molecular weight, low ionisation, high serum concentration, low protein binding, meningeal inflammation

Question 18

1) Give an example of an antibiotic that penetrates meninges at standard dose
2) Why cant many of these be used?

Answer 18

1) chloramphenicol, metronidazole

2) high resistance

Question 19

which antibiotics penetrate inflamed meninges or at high doses

Answer 19

benzylpenicillin and cephalosporins

Question 20

1) which antibiotics penetrate the BBB poorly

2) when are they used?

Answer 20

1) gentamycin

2) neonates as BBB isnt as developed

Question 21

1) Why is choramphenicol effective as meningitis treatment?
2) why isnt it used as first line meningitis ?
3) When would you use it?

Answer 21

1) v good penetration into CSF, activity against organisms which cause meningitis
2) - resistance in Hib and pneumococc
- bad side effects (aplastic anaemia, grey baby syndrome)
3) reserve agent for allergic patients

Question 22

1) Why is ceftoaxime and ceftriaxone used as first line antibiotic treatment for meningitisin adults and children
2) how often are each given

Answer 22

1) - activity against organisms which cause meningitis
- activity against penicillin resistant pneumococci and Hib
- well tolerated
- good penetration into CSF
2) Cefotax 6 hourly Ceftriax 12 hourly

Question 23

Which is the most active agent for pneumococcal meningitis?

Answer 23

benzylpenicilin (BUT increased incidence of low and high level resistance in pneumococci)

Question 24

Why isn’t benzylpenicillin used as first line for meningitis?

Answer 24

as its narrow spec -don’t use until know causative organism and what sensitive to

Question 25

What would affect antibiotic choice for meningitis?

Answer 25

• age
• clinical risks
• history of allergies
• gram results
• local and national sensitivity data

Question 26

what else could be prescribed to reduce long term morbidity in children with meningitis? one negative?

Answer 26

sterioids (dexamethasone)

BUT risk of GI bleed

Question 27

Which meningitis strains are covered in the conjugated vaccine given to babies? which other vaccines are available?

Answer 27

• Hib and men C

- meb B and polyvalent pneumococcal one

Question 28

When is chemoprophylaxis used in meningitis

Answer 28

secondary cases in close contacts and household of meningococcal and hib
- rifampicin and cipro clear nasopharyngeal carriage

Question 29

What is the presentation of a brain abscess

Answer 29

focal neurological signs, raised ICP, headache, fever (variable), raised CRP and ESR

Question 30

Name three ways a brain abscess could be acquired

Answer 30

• direct spread from venous e.g. ear + sinus infection
• haematogenous spread through blood from e.g. endocarditis
• direct implantation e.g. trauma surgery

Question 31

what bacteria are responsible for brain abscess ?

Answer 31

• strep milleri (from resp flora - cause other abscesses), anaerobes, enterobactiacae, s aureus, polymicrobials
• usually more than one organism

Question 32

WHich bacteria does chloramphenicol not cover?

Answer 32

listeria

Question 33

Why do you have to use benxypenicillin and cphalosporins and such a high doses

Answer 33

much less penetrative of BBB than choramphenicol

Question 34

if an organism is not isolated in gram stain of CSF, but a patients CSF and clinical findings are consistent with bacterial meningitis what do you prescribe

Answer 34

7-14 days ceftoazime or ceftriazone iv

Question 35

if you suspect brain abscess then what must you do?

Answer 35

CT scan NOT lumbar puncture as raised ICP

Question 36

Likely cause of multiple brain abscess?

frontal brain abscess? temporal?

Answer 36

1) haematogenous
2) venous from sinus
3) venous from ear

Question 37

Name two types of surgical management of brain abscesses and when they are indicated

Answer 37

drainage via 1) burr hole 2) craniotomy (if post traumatic or multinoculated or in posterior fossa)

Question 38

Describe the medical treatment of brain abscesses (not surgical) and how long ? determined by?

Answer 38

Abx -alone if neurology intact. got to know organism and source and
can only do alone if under 1.5cm

high dose ABX for 6-8 weeks 3 w i.v. then 3-5 w oral

clinical and radiological response and surgical intervention