Infectious Diseases of the Nervous System

Question 1

Symptoms of meningitis

Answer 1

Classic Triad: Only ~45% of patients have the complete classic triad of fever, headache, and neck stiffness (nuchal rigidity/meningismus), but nearly 100% of patients have at least 2 of 4 symptoms (fever, headache, nuchal rigidity, altered mental status).

Question 2

Parthenogenesis of bacterial meningitis

Answer 2

Bacteria reaches the subarachnoid space from the bloodstream (most common), adjacent intracranial infection (sinusitis, mastoiditis, otitis), congenital, traumatic or surgical defects in skull/spinal column

Bacterial cell wall components stimulate pro-inflammatory cytokines (e.g. TNF, IL-1), increase BBB permeability, and recruit neutrophils (PMNs). PMNs add to purulent exudates, and enhance cytotoxic edema via reactive oxygen species

Question 3

Diagnosis of bacterial meningitis

Answer 3

1. Lumbar Puncture
2. Blood cultures
3. Neuroimaging

Question 4

Indications to wait to do a LP in a suspected case of bacterial meningitis

Answer 4

1. decreased level of consciousness
2. focal neurologic deficits
3. papilloedema
4. new onset seizures
5. History of CNS disease or an associated condition (e.g. frontal sinusitis) that increases probability of brain abscess/empyema.
6. Immunocompromised
7. If above criteria are absent >97% have a normal CT.

Question 5

Most common organism in bacterial meningitis in neonates

Answer 5

Group B Strep

Question 6

Most common organism in bacterial meningitis in ages 2-23 months

Answer 6

S. Pneumo

Question 7

Most common organism in bacterial meningitis in ages 2-35 years old

Answer 7

Neisseria meningitidis
and
S. Pneumo

Question 8

Most common organism in bacterial meningitis in pts older than 35 years old

Answer 8

S. Pneumo

Question 9

What organism causes meningitis in 25% of cases involving pts over the age of 60 or immunocompromised?

Answer 9

Listeria monocytogenes

Question 10

CSF profile in bacterial meningitis

Answer 10

WBCs: High
Lots of PMNs
Glucose: low
Protein: High

Question 11

CSF profile in viral meningitis

Answer 11

WBCs: High (but not as high as bacterial)
Lots of lymphocytes
Glucose: Normal
Protein: Normal or slightly elevated

Question 12

Treatment of suspected bacterial meningitis in neonates

Answer 12

Ampicillin
+
Cefotaxime

Question 13

Treatment of suspected bacterial meningitis in children and adults

Answer 13

Ceftriaxone or Cefotaxime
+
Vanco

Question 14

Treatment of suspected bacterial meningitis in adults >50

Answer 14

Ceftriaxone or Cefotaxime 
\+ 
Vanco
\+
Ampicillin

Question 15

Corticosteroid administration in cases of suspected meningitis

Answer 15

Give before or at same time as 1st antibiotic

Question 16

Common causes of viral meningitis

Answer 16

Enterovirus
HSV2
Arboviruses

Question 17

Symptoms of viral meningitis

Answer 17

Headache, fever, meningeal irritation

Milder than bacterial

Question 18

Diagnosis of viral meningitis

Answer 18

1. CSF analysis
2. PCR
3. IgM if WNV

Question 19

Viral encephalitis

Answer 19

Viral encephalitis is an infection of brain tissue rather than just subarachnoid space (meningitis). Signs/symptoms usually much more extensive than for meningitis.

Question 20

Clinical symptoms of viral encephalitis

Answer 20

A. Common: Altered consciousness, fever, and headache.
B. Seizures and focal neurological signs/symptoms are common: personality change, alteration in mental status/level of consciousness (75-95%), aphasia (65-75%), hemiparesis (30-40%), ataxia (40%), cranial nerve palsies (30-35%), and visual field loss (10-15%).(% shown is for HSV encephalitis). Tremors, myoclonus, Parkinsonism seen in WNV.

Question 21

Most common causes of viral encephalitis

Answer 21

Arboviruses and HSV

Question 22

What is the goal when a pt walks in the door with suspected bacterial meningitis

Answer 22

Start Antibiotics within 60 minutes of patient arrival in the emergency room

Get blood cultures

Start corticosteroids

Question 23

What to start immediately in suspected cases of viral encephalopathy?

Answer 23

Acyclovir