Focal CNS infections Flashcards
General causes of brain absecesses
#1. Direct extension from contiguous site
#2. Hematogenous from distant site
#3. External
Direct extension from contiguous site for brain abcesses
Sinusitis
Dental abscess
Otitis
Mastoiditis
Direct extension from contiguous site
Pathogens
Streptococcus pneumoniae
Haemophilus influenzae
Anaerobes
Bacteroides, Prevotella
Staphylococcus aureus
Actinomyces,
Papilledema
Optic disc swelling that is due to raised intracranial pressure
STREPTOCOCCUS PNEUMONIAE
Characteristics
Refer to picmonic
STREPTOCOCCUS PNEUMONIAE
Risk factors
HIV
Diabetes
Steroid therapy
Asplenia
STREPTOCOCCUS PNEUMONIAE
Virulence factors
Surface protein adhesins
Allows colonization, binding to epithelial cells
Ig-A protease
Disrupts secretory Ig-A mediated clearance
Pneumolysin
Destroys respiratory epithelium
Capsule
Antiphagocytic
STREPTOCOCCUS PNEUMONIAE
Clinical disease
Sinusitis
Otitis
Common in children
Pneumonia
Lobar Rust-colored sputum
Meningitis
HAEMOPHILUS INFLUENZAE
Risk factors
Age
Asplenia
Chronic pulmonary disease Smoking
Alcoholism
#2. Hematogenous spread from distant site
causes
Endocarditis
Respiratory tract infection
Lung abscess
Mixed aerobes & anaerobes
Atypical organisms Nocardia
STAPHYLOCOCCUS AUREUS
Characteristics
Check picmonic
STAPHYLOCOCCUS AUREUS
Virulance factor- Toxin
Check picmonic
STAPHYLOCOCCUS AUREUS
Virulence factors
Enzymes
Staphylokinase
AKA fibrinolysin Dissolves fibrin clots
Actinomyces characterisitcs
Check picmonic
Craniotomy
Skin flora
Grampositive
Staphylococci(S.aureus,CONS)
Bacillus sp.
Propionibacter
Corynebacterium
