Meningitis

Question 1

Presence of ___ and ___ are absolute indications to obtaining an imaging study before performing an LP

Answer 1

Presence of papilledema and focal neurologic deficits are absolute indications to obtaining an imaging study before performing an LP

Question 2

LP analysis for meningitis should include:

Answer 2

• Opening pressure
• Closing pressure
• CSF glucose, protein, total + differential WBC
• CSF gram stain, fungal stain, culture
• Latex particle agglutination, HSV-PCR, EV-PCR, CSF-VDRL

Question 3

Approach to treating meningitis (without specific abx)

Answer 3

Generally speaking, you want to give empiric abx and acyclovir BEFORE THE DIAGNOSIS IS EVEN CONFIRMED

If you can do a quick blood draw and/or LP first, this may be warranted, as abx can confound serum and CSF cultures

Question 4

Kernig sign

Answer 4

Pain and resistance to complete extension of the knee when the hip ix flexed in the supine position

Caused by spasm in the hamstring muscles due to inflammation of the lumbosacral roots

Question 5

Burdzinski sign

Answer 5

An involuntar flexion of the hips and knees upon passive flexion of the neck, which may indicate meningeal irritation

Question 6

Latex particle agglutination

Answer 6

Surface of latex particles is coated with specific antigens or antibodies, forming “sensitized latex”

When a sample containing complemetary antigens or antibodies is mixed with the sensitized latex, visible agglutination is noted.

Used to detect H. influenzae type B, S. pneumoniae, and N. meningitidis

Question 7

Enteroviral load must be measured by. . .

Answer 7

. . . RT-PCR

As enteroviruses are ssRNA viruses

Question 8

Principal causes of bacterial meningitis inside and outside of the neonatal period

Answer 8

Neonatal: Streptococcus agalacticae, Listeria monocytogenes, E. coli

Outside neonatal: S. pneumoniae, N. meningitidis (+ H. influenzae B only if unvaccinated)

Question 9

Most common causes of viral meningitis in the US

Answer 9

• Enteroviridae (most common)
  
  • Coxsackie A
  • Coxsackie B
  • Echoviridae
• Herpesviridae (less common, but treatable with antivirals)
  
  • HSV
  • VZV
  • CMV
• Arborviridae (transmitted via arthropods, usually ticks)
  
  • St. Louis encephalitis virus
  • West Nile virus
  • Japanese encephalitis virus
  • Eastern equine encephalitis virus
  • Western equine encephalitis
  • La Cross virus

Question 10

Epidemiology of enteroviral meingitis

Answer 10

Spreads though the fecal-oral route and rarely the respiratory route

Outbreaks are associated pharyngitis and gastroenteritis and typically occur in late summer/early fall.

Question 11

Syndrome of mild flu-like symptoms, viral exanthem, pharyngitis, gastroenteritis that progreses to meningitis

Answer 11

Full of red flags for enteroviral meingitis, especially Coxsackie meingitis (depending on the distribution of the viral exanthem)

Question 12

Complications of meningitis

Answer 12

• Thrombotic stroke (due to peri-vascular inflammation)
• Dysphagia/aspiration
• Communicating hydrocephalus
• Non-communicating hydrocephalus
• Venous sinus thrombosis

Question 13

Meningitis with high fever, widespread maculopapular rash, and presence of purpura/ecchymosis

Answer 13

Neisseria meningitis

Question 14

Viral vs bacterial meingitis CSF characteristics (Table)

Answer 14

Question 15

Timeframe regarding antibiotic administration and the sensitivity/specificity of CSF gram stain and culture

Answer 15

While it is optimal to get CSF prior to administering abx from a diagnostic perspective, if you it within 2 hours of starting abx the sensitivity and sensitivity are only mildly reduced.

After 2 hours, the odds start to drop more precipitously

Question 16

CSF viral culture

Answer 16

Slow and poor sensitivity

PCR-based studies are far superior

Question 17

Neuroimaging studies in meningitis (bacterial and viral)

Answer 17

Typically normal in both bacterial and viral. However, HSV is a key exception

HSV often shows evidence of hemorrhagic inflammatory damage in the temporal region

Generally, imaging is done in order to rule out non-communicating hydrocephalus for LP rather than for diagnostic purposes

Question 18

Typical first-line agents for bacterial meningitis

Answer 18

(Penicillin G OR Ampicillin) + 3rd generation cephalosporine (usually ceftriaxone)

Question 19

Coverage of ampicillin for meningitis-causing bacteria

Answer 19

Ampicillin covers meningococci, listeria, and most pneumococci

Question 20

Coverage of third generation cephalosporines for meningitis

Answer 20

Ceftriaxone or cefotaxime are the typical agents.

Cover gram-negatives as well as ampicillin-resistant H. influenzae.

Question 21

When do we add vancomycin to the empiric meningitis antibiotic regimen?

Answer 21

1. Vanc is added to cover for Staph aureus when patients ahve undergone recent neurosurgical procedures or had recent head trauma
2. If sensitivities of S. pneumoniae strain are unknown, adding vancomycin is also appropriate (as some S. pneumoniae are resistant to third generation cephalosporines)

Question 22

Coverage of Penicillin G for meningitis

Answer 22

Used to treat gram-negative cocci (Neisseria) and gram-positive bacilli

Question 23

When do we add aminoglycosides to a bacterial meningitis regimen?

Answer 23

If gramp-positive bacilli or gram-negative bacilli are identified

Question 24

Meningitis algorithm

Answer 24

Question 25

Adjuvant therapy with IV corticosteroids in meningitis

Answer 25

Clearly indicated in childhood meningitis, 100% of the time

Less clear for adults, but seems to prevent severe complications and neurologic deficits in S. pneumoniae meningitis.

Notably, there is evidence to suggest that corticosteroids decrease the penetration of vancomycin into the CSF.

Question 26

A finding of normal CSF glucose is very uncommon in ___ meningitis

Answer 26

A finding of normal CSF glucose is very uncommon in bacterial meningitis

Question 27

Evolution of CSF findings in viral meningitis

Answer 27

• Early in viral meningitis, a preponderance of neutrophils may be seen in the CSF
• As the illness progresses, a lymphocytic pleocytosis predominates with gradually rising protein
• Glucose remains relatively normal throughout this entire process

Question 28

H. influenzae B are often described as __ on gram stain

Answer 28

H. influenzae B are often described as gram negative coccobacilli on gram stain