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Flashcards in CNS Infections Deck (69)
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1

Define Meningitis

Swelling and inflammation of the membranes covering the brain and spinal cord

2

Define Encephalitis

Inflammation of the brain

3

Define Nosocomial Infections

Hospital acquired

4

Define Abscess

Confined pocket of pus that collects in tissues, organs, or spaces inside the body

5

Community Bacterial Meningitis Bugs (Newborn-1 month)

Group B Strep- 70%
H. influenzae, Listeria, S. pneumoniae- 30%

6

Community Bacterial Meningitis Bugs (1-23 months)

S. pneumoniae- 50%
N. meningitidis- 30%
Group B. Strep- 15%

7

Community Bacterial Meningitis Bugs (2-18 years)

N. meningitidis- 60%
S. pneumoniae- 25%
H. influenzae- 8%

8

Community Bacterial Meningitis Bugs (19-50 years)

S. pneumoniae- 60%
N. meningitidis- 20%
H. influenzae- 10%
Listeria- 6%

9

Community Bacterial Meningitis Bugs (50+)

S. pneumoniae- 70%
Listeria- 20%
N. meningitidis, group B strep, H. influenza- 10%

10

Nosocomial Bacterial Meningitis Epidemiology

Disease of neurosurgical patients, trauma, etc

11

Nosocomial Bacterial Meningitis Bugs

E. coli, K. pneumoniae, P. auruginosa- 33%
Strep-9%
S. aureus- 9%
Coagulase negative staph- 9%
Listeria- 8%

12

Changes in Epidemiology for Bacterial Meningitis

Decline in H. influenza
Increased incidence of S. pneumo
Shift from pediatrics to adults
Increase incidence of antibiotic-resistant organisms (PCN & Cephalosporin)

13

Predisposing Factors of Bacterial Meningitis

Colonization of the nasopharynx (N. meningitides, S pneumonia, H. influenza)
Direct entry of organisms into the CNS from contiguous infection, trauma, neurosurgery, a CSF leak, or medical device

14

Host Risk Factors for Bacterial Meningitis

Asplenia
Corticosteroid use
immune-compromised/HIV infection
Exposure to someone with menigitis

15

Pathogenesis of Bacterial Meningitis

Virulence factors of pathogen
CSF has inadequate humoral immunity
Bacteria produce inflammatory response
Leads to vasogenic brain edema, increase ICP, brain ischemia, cytotoxic injury & neuronal apoptosis

16

Presentation of Bacterial Meningitis

Symptoms of 2-3 days
FEVER >38 C
NUCHAL RIGIDITY
CHANGE IN MENTAL STATUS

17

Other Symptoms of Bacterial Meningitis

Headache
Photophobia
Characteristic rash
N/V
Seizures
Focal neurological deficits
Papilledema

18

Exanthem

Small hemorrhages under the skin
Rash doesn't fade under pressure

19

Exanthem Pathogenesis

Septicemia
Wide spread endothelial damage
Activation of coagulation
Thrombosis
Platelet aggregation
Reduction of platelets

20

Physical Exam Tests

Kerning Sign
Brudzinski Sign

21

Kerning Sign

Supine position, flex hip 90 degressm inability or reluctance to allow full extension of the knee when the hip is flexed

22

Brudzinski sign

Spontaneous flexion of hips during attempted passive flexion of the neck

23

Meningitis Workup

CBC with differential
CMP
UA
Blood cultures
Lumbar Puncture
Possible CT

24

Head CT prior to LP for Meningitis

Immunocompromised
Hx of seizure

25

Reasons for CT in Bacterial Meningitis

Identify contraindications to LP
Evidence of head trauma, sinus/mastoid infection, skull fracture, & congenital anomalies
May identify cerebral edema, effusion, hydrocephalus, abscess
Reveal cause of infection

26

Normal LP values

Pressure: 70-180
Appearance: clear, colorless
CSF protein: 15-45 mg/dL
Gamma globulin: 3-12% of protein
CSF glucose 45-85 mg/100mL (OR >2/3 serum)
CSF WBC:

27

Bacterial Meningitis LP

Elevated opening pressure
Cloudy, purulent
Leukocytosis (1000 to 5000)
Protein 100-500 mg/dL
Glucose

28

Gram Positive Diplococci in Bacterial Meningitis

S. pneumoniae

29

Gram Negative Diplococci in Bacterial Meningitis

N. meningitidis

30

Small Pleomorphic Gram Negative Coccobacilli in Bacterial Meningitis

H. influenzae