Infectious Disorders of the CNS

Question 1

Bacterial meningitis empirical Abx - Neonates

Answer 1

Ampicillin + Cefotaxime

Question 2

Bacterial meningitis, empirical Abx - Children/Adults, 2-50 years

Answer 2

Vancomycin AND Ceftriaxone/Cefotaxime

Question 3

Bacterial meningitis, empirical Abx - Adults > 50

Answer 3

Vancomycin AND Ampicillin AND Ceftriaxone/Cefotaxime

Question 4

Bacterial meningitis, empirical Abx - Immunocompromised/Nosocomial/Head Trauma/Neurosurgery

Answer 4

Cefepime AND Vancomycin

+/- Ampicillin

Question 5

Which HSV causes meningitis vs. encephalitis in adults?

Answer 5

HSV-2 generally causes meningitis

HSV-1 generally causes encephalitis

Question 6

What are the two most common causes of viral encephalitis?

Answer 6

HSV-1

WNV

Question 7

Classic MRI finding of herpes encephalitis

Answer 7

Fronto-temporal hyperintensity???

Question 8

Treatment for herpes encephalitis

Answer 8

Acyclovir

Question 9

Bacterial meningitis - most common organism, neonates < 2 months

Answer 9

Group B Strep (50%)

Question 10

Bacterial meningitis - most common organism, children 2 months - 2 years

Answer 10

Streptococcus pneumoniae (50%)

Question 11

Bacterial meningitis - 2 most common organisms, children/adults 2-34 years

Answer 11

Neisseria meningitides (40%)

Streptococcus pneumonia (40%)

Question 12

Bacterial meningitis - most common organism, adults > 35 years

Answer 12

Streptococcus pneumonia (50-70%)

Question 13

Common organism causing bacterial meningitis in adults > 60

Answer 13

Listeria monocytogenes

Question 14

Viral meningitis - CSF

Answer 14

Elevated WBCs (10-2,000/mL), primarily lymphocytes

Normal Glucose

Normal - slightly elevated protein

PCR amplification of viral genomic material from CSF

Elevated ratio of CSF/serum antibody titer (IgM)

Question 15

Viral meningitis - 2 most common pathogens

Answer 15

Enterovirus (70%)

HSV-2

Question 16

Classic Triad of Bacterial Meningitis

Answer 16

Fever
Headache
Nuchal rigidity

Accounts for 45% of all cases

+ AMS, any 2/4 is 95% sensitive

Question 17

Etiologies of bacterial meningitis

Answer 17

Hematological spread (most common)

Adjacent intracranial infection (sinusitis, mastoiditis, otitis)

Skull/spinal defects (congenital, traumatic, surgical)

Question 18

Goal of bacterial meningitis treatment

Answer 18

Initiation of antibiotic therapy within 60 minutes of patient arrival in the ER

Question 19

LP findings in bacterial meningitis

Answer 19

Elevated WBCs (100-10,000/mL) - majority (>80%) neutrophils

Elevated Protein (>50g/dL)

Low glucose (<0.4

Bacterial culture positive in 70-85%

Question 20

Indications for imaging before LP

Answer 20

Focal deficits / AMS

Signs of increased ICP (papilloedema)

Suspected focal CNS infection/lesion

Immunocompromised

*Get blood cultures and start immediate empiric antibiotics first!

Question 21

Streptococcal meningitis - demographics and treatment

Answer 21

Children 2 years - adults > 35 years

Vancomycin + 3rd generation cephalosporin

10-14 days

Question 22

Meningococcal meningitis - demographics and treatment

Answer 22

Children/adults 2-34 years

Vancomycin + 3rd generation cephalosporin

> 7 days

Question 23

Listeria monocytogenes - demographics and treatment

Answer 23

Adults > 60 years

Ampicillin +/- aminoglycoside

> 21 days

Question 24

Brudzinski Sign

Answer 24

With the patient supine, forced flexion of the neck elicits a reflex flexion of the hips

+ in meningitis

Question 25

Kernig sign

Answer 25

With the patient supine and hip and knee both flexed at 90 degrees, subsequent extension of the knee past 90 degrees is painful + in Meningitis