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Flashcards in Focal CNS infections Deck (21):
1

General causes of brain absecesses 

 #1. Direct extension from contiguous site

 #2. Hematogenous from distant site

  #3. External

2

Direct extension from contiguous site for brain abcesses

 Sinusitis

 Dental abscess

 Otitis

 Mastoiditis

3

Direct extension from contiguous site

 Pathogens

Streptococcus pneumoniae

 Haemophilus influenzae

 Anaerobes

      Bacteroides, Prevotella

 Staphylococcus aureus

 Actinomyces,

4

Papilledema

Optic disc swelling that is due to raised intracranial pressure

5

STREPTOCOCCUS PNEUMONIAE 

Characteristics 

Refer to picmonic

6

STREPTOCOCCUS PNEUMONIAE

Risk factors

 HIV

 Diabetes

 Steroid therapy

 Asplenia

7

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

8

STREPTOCOCCUS PNEUMONIAE

 Clinical disease

 Sinusitis

 Otitis

     Common in children

 Pneumonia

     Lobar

     Rust-colored sputum

 Meningitis

9

HAEMOPHILUS INFLUENZAE

Risk factors

 Age

 Asplenia

 Chronic pulmonary disease  Smoking

 Alcoholism

10

#2. Hematogenous spread from distant site

causes 

 Endocarditis

 Respiratory tract infection

     Lung abscess

 Mixed aerobes & anaerobes

     Atypical organisms

      Nocardia

11

STAPHYLOCOCCUS AUREUS 

Characteristics 

Check picmonic 

12

STAPHYLOCOCCUS AUREUS

Virulance factor- Toxin

Check picmonic

13

STAPHYLOCOCCUS AUREUS

 Virulence factors

 Enzymes

 Staphylokinase

      AKA fibrinolysin

      Dissolves fibrin clots

14

Actinomyces characterisitcs 

Check picmonic 

15

 Craniotomy

 Skin flora

 Grampositive

 Staphylococci(S.aureus,CONS)

 Bacillus sp.

 Propionibacter

 Corynebacterium

16

 Craniotomy

Nosocomial pathogens

 Enterobacteriaceae

 Klebsiella

 E. coli

 MRSA

 Resistance

17

 JC virus

 “Progressive multifocal leukoencephalopathy”

 Demyelinating disease of white matter

 Reactivation of virus when individual becomes immunosuppressed

 HIV(CD4<50mm3),organ transplantation, chemotherapy

18

JC VIRUS / PML

 Diagnosis

 Lumbar puncture

 “Bland” CSF

 Detection of myelin basic protein

 As result of demyelination

 Also seen in multiple sclerosis

 CSF JC virus PCR

19

EBV CD4 count

Lymphoma CD4 <50 mm

20

Toxoplasmosis CD4 count

CD4 <100

21

ASPERGILLUS vs mucor 

Aspergillus 

 Narrow

 Septated hyphae

 Acute angle branching (typically 45 degrees)

 

mucor

 Broad,nonseptate,widerangles