brain abscesses and other infections of the central nervous system

Question 1

define brain abscess

Answer 1

focal suppurative process within the brain parenchyma

Question 2

what are the main causes of brain abscess

Answer 2

bacterial
fungal
polymicrobial

Question 3

what is the main bacterial pathogen which causes brain abscesses

Answer 3

streptococci (streptococcus milleri)

Question 4

what 4 clinical settings do brain abcessess develop in.

Answer 4

direct spread- continuous supparative focus e.g. ear or sinus.
Haematogenous spread from a distant focus via bloodstream e.g. endocarditis (heart), bronchiectasis (lungs) (often multiple abscesses).
Trauma- post neurosurgery
Cryptogenic (no known cause)- no focus, commonly found in immunocompromised people as they have had the breakdown of the muscosal barrier and have access devices such as hickman lines.

Question 5

clinical presentation of patient with brain abcesses

Answer 5

headache- most common
focal neurological deficit
confusion- generalised neurological deficit.
fever
nausea and vommitting
dizziness, seizures
neck stiffness
(papilloedema), coma- optic nerve swelling.

Question 6

main treatment of choice for brain abscess

Answer 6

drainage

Question 7

is the abscess in small drainage may not be used as treatment, what might be used ins tea

Answer 7

antibiotics

Question 8

why is drainage the best option for treatment of brain abscess.

Answer 8

reduce ICP- can causes seizures and coms
confirm diagnosis- CT not 100%
obtain pus fro micobiological investigation.
to enhance efficacy of antibiotics
to avoid spread of infection to ventricles.

Question 9

why are oral ampicillin, penicillin not used to treat brain abscesses.

Answer 9

they are not targeted to the right place. e.g. CSF and CNS

Question 10

which antibiotics are used to treat brain abscesses.

Answer 10

cefuroxime (penetrate brain and CSF))
cefotaxime, ceftazidime (works against pseudomonal aspergilloma)
metronidazole achieve therapeutic concentrations in intracranial pus

Question 11

unto how many weeks after surgery are antibiotics given to patients who had a brain abscess

Answer 11

4-6 weeks and then have a oral switch.

Question 12

complications of a brain abscess

Answer 12

Raised intracranial pressure, mass effect.

Rupture (usually into ventricles) causing ventriculitis

Question 13

what is the mortality rate if the brain abscess speeds to the ventricles

Answer 13

100%

Question 14

define subdural empyema

Answer 14

Infection between dura and arachnoid mata-

Question 15

most common pathogenic organisms to cause subdural empyema

Answer 15

often polymicrobial
anaerobes, streptococci, aerobic gram negative bacilli, streptococcus pneumoniae, haemophilius influenza and staphylococcus aureus (after surgery)

Question 16

pathogenesis of subdural empyema

Answer 16

spread of primary infection from sinuses (most common) , middle ear and mastoid or distant site` and following surgery or trauma- but it does not enter the brain parenchyma it is stopped by the dura.

Question 17

most common site of origin of infection of subdural empyema

Answer 17

sinuses

Question 18

what is the clinical presentation of a patient with subdural empyema

Answer 18

headache, fever, focal neurological deficit, confusion, seizure, coma due to increased pressure.

Question 19

how is subdural empyema treated

Answer 19

surgical drainage of pus
antimicrobial agents (guided by culture of pus results)

Question 20

Is a Ventriculoperitoneal (VP) shunt permanent or temporary

Answer 20

permanent

Question 21

what age groups present with Ventriculoperitoneal (VP) shunt

Answer 21

children

Question 22

is a external ventricular drain (EVD) permanent of temporary

Answer 22

temporary.

Question 23

in what conditions is a external ventricular drain (EVD) inserted to drain CSF

Answer 23

hydrocephalus.

Question 24

how can Ventriculoperitoneal (VP) shunt and external ventricular drain (EVD) cause infection.

Answer 24

can become colonised with organisms that subsequently cause ventriculitis (often peritonitis)

Question 25

2 main functions of external ventricular drain (EVD)

Answer 25

monitor ICP, and drain excess fluid.

Question 26

how are Ventriculoperitoneal (VP) shunt and external ventricular drain (EVD) infections diagnosed

Answer 26

CSF microscopy and cultures

Question 27

most common cause of Ventriculoperitoneal (VP) shunt and external ventricular drain (EVD) infections

Answer 27

coagulase negative staphylococci- common skin flora

Question 28

treatment for Ventriculoperitoneal (VP) shunt and external ventricular drain (EVD)

Answer 28

device removal, intraventricular antibiotics

Question 29

how doe we administer and antibiotics

Answer 29

start smart and then focus.