CP27 - Brain abscess and other CNS infection Flashcards
what are the different types of primary bacterial infection of the CNS
Meningitis Encephalitis Ventriculitis Brain Abscess Ventriculoperitoneal shunt and external ventricular drain infection subdural empyema eye infections
what is a brain abscess
focal suppurative process within the brain parenchyma (pus in the substance of the brain)
what are some of the most common agents which causes brain abscess
streptococci, staphylococcus aureus, anaerobes, gram -ve enteric bacteria (E.coli)
how does brain abscess develop?
in 4 clinical settings,
direct spread from contiguous suppurative focus
haematogenous spread from a distant focus - endocarditis etc
trauma
cryptogenic (obscure or uncertain origin)
what are some of clinical presentation of brain abscess
Headache (most common)
Focal neurological deficit (30-50%)
Confusion
Fever (
what are the management of brain abscess
drainage (small abscess can be treated with antibiotic alone)
why do you drain the brain?
to reduce intra-cranial pressure
confirm diagnosis
obtain pus for mircobiological investigation
enhance efficacy of antibiotics
avoid spread of infection into the ventricles
why are antibiotics treatment for the brain abscess is different to normal bacterial infection?
physiological properties of blood-brain barrier and blood CSF-barrier are distinct
penetration of drugs into CSF and brain tissue differ
what are some of the examples of drugs which can be used to penetrate blood brain barrier
ampicillin, penicillin, cefuroxime, cefotaxime, ceftazidime, and metronidazole achieve therapeutic concentrations in intracranial pus
what are some of the complications for brain abscess
raised intracranial pressure, mass effect - coning
rupture (usually into ventricles - ventriculitis)
what is coning
brainstem being pushed down through foramen magnium
what is subdural empyema?
it is infection between dura and arachnoid matter
what can cause subdural empyema
anaerobes, streptococci, aerobic Gram negative bacilli, Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus
what is the pathogenesis of subdural empyema?
spread from sinuses, middle ear and mastoid or following surgery or trauma
what are some clinical presentation of subdural empyema
headache, fever, focal neurological deficit, confusion, seizure, coma
