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Flashcards in CNS Infections I Deck (37)
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1

clinical features of CNS infection

Fever, headache, altered mental status, or focal neurologic deficits

2

what are the routes of infections for CNS infections

-Hematogenous dissemination
-direct injury
-neural tissue (rare)

3

what is trojan horse

it is a method of microbes to spread through the blood where they infect WBCs then the WBC squeeze through the barrier to get into the cell

4

what is encephalitis and myelitis

encephalitis - inflammation of brain parenchyma
myelitis - infection of spinal cord

5

what are abscesses

localized infection in the brain or spinal cord

6

universal epidemiological considerations

age, season, geography, medical condition/underlying disease

7

how do you diagnose CNS infection

lumbar puncture and neuroimaging like CT or MRI (done before lumbar puncture)

8

what are some risks to doing a lumbar puncture

-headaches
-infection
-temporary pain or numbness to legs or lower back pain
-risk of bleeding into spinal canal
-ICP could be due to cerebral mass lesion and lumbar puncture --> brain herniation

9

normal pressure in the CSF

70-180mm H2O

10

how is a lumbar puncture performed

CSF is drawn from between two vertebrae with patient in the lateral decubitus position

11

appearance of normal and abnormal CSF

normal - clear, colorless
abnormal - cloudy/turbid

12

what are routine tests for CSF

WBC count with differential, RBC count, [Glucose], [protein], gram stain, bacteria culture

13

normal CSF value for WBC, RBC, glucose, protein

WBC - 0-5/mm3 for children and adults then 32/mm3 for neonates
RBC - none
glucose - 40-70mg/dL
protein: newborn is 150mg/dL and then from 6 months on it is 18-58mg/dL

14

typical findings in meningitis for bacteria: pressure, WBC count, cell differential, protein, glucose

pressure elevated
WBC: greater than 1000/mm3
mainly neutrophils
protein 100-500mg/dL
glucose 0-10mg/dL

15

typical findings in meningitis for viral: pressure, WBC count, cell differential, protein, glucose

normal pressure
WBC: less than 100/mm3
mainly lymphocytes
protein 50-100mg/dL
glucose 40-70mg/dL

16

typical findings in meningitis for fungal: pressure, WBC count, cell differential, protein, glucose

variable pressure
variable WBC
lymphocytes (and PMNs)
protein 50-100mg/dL
glucose less than 40mg/dL

17

typical findings in meningitis for tuberculosis: pressure, WBC count, cell differential, protein, glucose

variable pressure
variable WBC
lymphocytes
protein 10-500mg/dL
glucose 20-40mg/dL

18

clinical features of acute meningitis

• Onset: hours-several days
• Life-threatening
• Meningism: Fever, Headache, Nuchal rigidity, Nausea & Vomiting, Photophobia
• Altered mental status

19

features of aseptic meningitis

– Increased lymphocytes
– Self limiting
– Viral or non infectious (Absence of cultivable bacteria or fungi)

20

features of chronic meningitis

--rare
– Slow onset (period of weeks)
– ↓ Fever, lethargy
– TB, Fungi & (Protozoa)

21

tests for meningism

• Inability to flex neck (chin to chest)
• Inability to oppose nose with knee
• Tripod sign: Inability to sit up without using hands
• Kernig’s sign: inability to fully straighten leg when in laying position and leg is pulled up
• Brudzinski’s sign: child is flat on back and when neck pulled up, knees come up too

22

bacterial causes of meningitis in neonates and infants

neonates: S. agalactiae (group B strep) and E. coli, L. monocytogenes

infants: S. pneumonia (N. meningitides and H. influenza)

23

bacterial causes of meningitis in adolescents and adults

adolescents: S. pneumonia (N. meningitides and H. influenza)

adults: N. meningitides, S. pneumonia

24

bacterial causes of meningitis in adults greater than 50 years old

S. pneumonia (N. meningitides, L. monocytogenes and gram negs)

25

most frequently observed in children and adults with meningitis

Strep pneumonia

26

where is strep pneumonia found in the human body

throat and nasopharynx

27

strep pneumonia is associated with what conditions

previous pneumonia infections, otitis media, mastoiditis, sinusitus, endocarditis

28

basilar skull fracture and CSF leak is associated with what bacteria in association with bacterial meningitis

Strep pneumonia

29

what type of bacteria is strep pneumonia? where does it get its virulence?

gram positive diplococci
virulence from capsule, pneumolysin, IgA protease

30

clinical features of strep pnuemonia

rapid 1-2 days
impaired consciousness common