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Flashcards in 13: CNS infections Deck (35):
0

Chronic meningitis

At least 4 weeks of sx*

1

Meningitis- cc

Bacteria- S. pneumonia, N. meningitidis, H. influenzae
Virus- Echo, Enterovirus, HSV, HIV, CMV, EBV
Protozoa- Naegleria fowleri, Acanthamoeba
Spirochetes- Neurosyphilis

2

0-4 weeks

S. agalactiae (group B strep)*
Listeria

3

4-12 weeks

S agalactiae* (group B strep)
E coli
H influenzae

4

3month- 18yrs

N meningitidis*
S pneumoniae

5

18-50yrs

S pneumoniae*
N meningitidis

6

>50yrs and Immunocompromised

S pneumoniae*
N meningitidis
Listeria
Aerobic Gram (-) bacilli

7

Intracranial manipulation

S aureus*
Goagulase (-) staph
Aerobic Gram (-) bacilli

8

Basilar skull fracture

S pneumoniae*
H influenzae

9

CSF shunts

S aureus*
Aerobic Gram (-) bacilli

10

Acute meningitis

Hrs to a few days of onset

11

Signs of meningeal irritation

Kernigs sign (elevate the leg and extend the knee-> pain at the back of the thigh)
Brudzinski sign (Flex the neck and the hips and knee will also bend)
Nuchal rigidity (less severe in viral)

the 2 signs are absent in viral infection

12

Signs of ICP

Deteriorating level of consciousness
Papillaedema (blurring of optic disc margins)
Dilated, poorly reactive upil
Cushing's reflex (Bradycardia, Hypertension, Irregular respiration)

13

Systemic keys to the etiology

Direct extension- Sinusitis or Otitis
Basilar skull fracture- Rhinorrhea or Otorrhea
Infective endocarditis- Murmur
Erythematous maculopapular rash- Meningococcemia

14

Lumbar puncture

Key- Posterior superior iliac spine-> gap is L3-L4
Puncture on either L3-4 or L4-5 with more space

15

Bacterial- dx

WBC: 100-5000; >80% PMNs
Glucose: 100

16

Viral- dx

WBC: 10-300; lymphocytes
Glucose: Normal
Protein: Normal

17

Tuberculous- dx

WBC: 100-500; lymphocytes
Glucose: same as bacteria
Protein: same as bacteria

18

S pneumoniae- tx

DOC: 3rd generation cephalosporins (ceftriaxone or cefotaxime) + vancomycin for 2 weeks
or PenG

19

N meningitidis- tx

DOC: PenicillinG or Ampicillin x 7days
for Resistant strains-> Ceftriaxone or Cefotaxime

20

H influenzae- tx

DOC: Ceftriaxone or Cefotaxime

21

Aerobic Gram(-) bacilli- tx

DOC: Ceftriaxone or Cefotaxime x3wks

22

P aeruginosa- tx

DOC: Ceftazidime (still 3rd gen but others are not effective**)

23

Staphylococcus species- tx

Nafcillin or Oxacilliin
Vancomycin-> MRSA, Coagulase(-) Staph

24

Use of Steroids

To attenuate the detrimental effects of inflammatory response due to IL-1 and TNF
MUST be given BEFORE the antibiotic therapy (killing of bacteria will worsen the immune response-> suppress immune before killing bugs)**
20mins before first dose of antimicrobial agent**

25

Most important dx tool for CNS viral infection

PCR amplification
Investigation of choice for Enteroviruses, HSV, CMV, EBV

26

Viral meningitis- tx

Acyclovir for HSV
Vaccination: MMR, VZV

27

Viral encephalitis- cc

They show tropism to specific tissue
Arbo virus
Enterovirus (Polio: LMN)
HSV-1 (Limbic system in Temporal lobe)

28

Arbo virus

US: Eastern Equine Encephalitis virus (EEE)
World: Japanese Encephalitis virus

29

HSV-1 encephalitis- sx

Olfactory hallucinations
Personality changes

due to its effect on Limbic system/ Temporal lobe
Perivascular inflammatory infiltrates and Inclusion bodies usually present

30

Encephalitis- dx

CSF PCR**
EEG: Periodic lateralized epileptiform discharges (PLEDs)**- sudden repeated spikes
MRI: most sensitive

31

Cerebral abscess- sites

Temporal lobe: Otits media, Mastoiditis
Posterial frontal/parietal lobe: Hematogenous spread
Interface of gray-white matter: Metastatic abscess

32

Cerebral abscess- cc

S aureus- MC**
Mycobacteria, Toxoplasma gondii, Cryptococcus- Immunocompromised*

33

Cerebral abscess- stages

1: Early cerebritis stage (day 1-3)
2: Late cerebritis stage (day 4-9)
3: Early capsule formation stage (day 10-13)- ring enhancing capsule on MRI
4: Late capsule formation stage (>14 days)

34

Cerebral abscess- tx

3rd gen cephalosporins
Surgical aspiration and drainage for lesion >2.5cm*
Anti-convulsant
Steroids (Dexamethasone)