27 Brain abscess and other CNS infections.

Question 1

What are the bacterial causes of brain abscess? (4)

Answer 1

Often polymicrobial.
60% Streptococcus milleri.
Staph aureus if trauma/surgery.
E.coli.
Pseudomonas.

Question 2

What are the insidious causes of brain abscess? (4)

Answer 2

M tuberculosis.
Toxoplasma gondii.
Nocardia.
Actinomyces.

Question 3

What are the pathogeneses of brain abscess? (4)

Answer 3

Contiguous spread: ear/teeth.
Haematogenous (endocarditis).
Trauma (inc surgery).
Cryptogenic.

Question 4

What is the presentation of a brain abscess? (7)

Answer 4

Headache, dizziness, seizures.
Focal neurological deficit.
Fever, N+V.
Neck stiffness.

Question 5

How are brain abscess managed?

Why? (5)

Answer 5

Drainage.

Reduces kPa, confirms diagnosis, pus for microbiology, enhance antibiotic efficacy, avoid ventricular spread.

Question 6

Which antibiotics achieve therapeutic concentration in intracranial pus? (6)

Answer 6

Ampicillin
Penicillin
Cefuroxime
Cefotaxime
Ceftazadime
Metroniadzole

Question 7

What are the complications of a brain abscess? (4)

Answer 7

Raised intracranial pressure.
Mass effect.
Coning.
Rupture and ventriculitis.

Question 8

What is a subdural empyema?

Answer 8

Infection between dura and arachnoid matter.

Question 9

What are the causes of a subdural empyema? (5)

Answer 9

Anaerobes.
Streptococci.
S.pneumoniae
H.influenzae
S.aureus.

Question 10

What is the pathogenesis of a subdural empyema? (4)

Answer 10

Spread from sinuses, middle ear or blood.

Trauma/surgery.

Question 11

What is the most common cause of a external ventricular drain infection?
Treatment?

Answer 11

Coagulase -ve staphylococci.

Device removal and IV antibiotics.

Question 12

What is the presentation of a subdural empyema? (5)

Answer 12

Headache
Fever
Neurological deficit
Seizure
Coma

Question 13

How are subdural empyemas managed?

Answer 13

Drainage of pus.

Antibiotics.