Bacterial Meningitis Study Guide - Dr. Smith

Define meningitis

inflammation of the meninges (leptomeninges (pia mater and arachnoid space) coverings of the brain and spinal chord

What are the different types of meningitis?

- bacterial***

- aseptic (non-bacterial)

- infectious

- viral

- fungal

- TB

- parasites

- non-infectious

- cancer

- SLE

- head trauma

- brain surgery

What are the 3 layers of the brain

dura mater (2 layers)

arachnoid

pia mater

What race has a higher reported rate of meningitis than other ethnic groups?

African Americans

What age group has the highest mortality with Listeria monocytogenes?

neonates

What pathogens cause Community acquired meningitis?

- streptococcus pneumoniae

- haemophilus influenzae

- neisseria meningitidis

- group b streptococcus (Streptococcus agalactiae)

- listeria monocytogenes

Development of bacterial meningitis

- mucosal colonization and bacterial invasion

- bacterial replication in subarachnoid space

- neuronal damage due to increased ICP and cerebral edema

Transmission of meningitis

- nasopharyngeal colonization***

- maternal vaginal flora to neonates

- immunocompromised or neonates

- direct inoculation of bacteria

Transmission of meningitis: nasopharyngeal colonization

most common

pathogens

- neisseria meningitidis

- streptococcus pneumoniae

- haemophilus influenza type b

Transmission of meningitis: maternal vaginal flora to neonates

pathogens

- group b streptococcus

- e. coli

Transmission of meningitis: immunocompromised or neonates

pathogens

- listeria monocytogenes

- acquired by certain foods and passed to neonates via placenta or genitals at birth

Transmission of meningitis: direct inoculation of bacteria

- injuries

- indwelling catheters

- extension of infection (otitis media)

What are the risk factors of meningitis?

- extreme age (neonate, infants, elderly)

- exposure to crowds (school, dorms)

- disease process (immunocompromised, asplenia, cochlear implants)

- smoking

- travel

- vaccination status

What are the clinical presentations of meningitis?

- fever***

- altered mental status***

- stiff neck***

- chills

- photophobia

- phonophobia

- vomiting

- severe headache

What are the clinical presentations of meningitis in neonates/infants?

- bulging fontanelle

- apneas

- irritable/lethargic

- vomiting

- blank starring expression

- poor feeding

- purpuric or petechial rash

- seizures

What is the triad for meningitis?

fever, stiff neck, and altered mental status

What are the focal neurological deficits in meningitis?

Brudzinski's sign

- supine position and knees raise at the same time as head

Kernig's sign

- supine position, knee 90 angle, pain in back

What pathogen usually causes purpura and petechial skin rash?

Haemophilus influenza

Meningitis diagnosis

- lumbar puncture (L3/L4)

- blood cultures

- PCR

- CT or MRI

What conditions would require a CT scan or MRI for a meningitis diagnosis

- immunocompromised

- history of CNS disease

- new onset seizure

- papilledema

- abnormal neuro findings

- focal neurological deficit (Kernig/Brudzinski signs)

What factors would affect lumbar puncture procedure?

- papilledema

- neurological deficit

- new onset seizure

- delay in Lumbar puncture

What factors are acceptable for lumbar puncture procedure?

- immunocompromised

- history of CNS disease

If the patient does NOT meet exclusion criteria for lumbar puncture, what is the next step?

- obtain blood cultures and STAT lumbar puncture

- empiric antibiotics and dexamethasone

If the patient MEETS exclusion criteria for lumbar puncture, what is the next step?

- obtain blood cultures STAT

- empiric antibiotics and dexamethasone

- head CT

- perform LP (last step)

What can happen to a patient if a lumbar puncture is performed and they MEET the exclusion criteria?

the patient can experience herniation and die

What are the therapeutic goals for bacterial meningitis?

- eradication of infection

- improvement of signs/symptoms

- reduce mortality and morbidity

- provide supportive care

When should you initiate empiric treatment for bacterial meningitis?

with 60 minutes of arrival to hospital

How much delayed time can increase mortality if empiric treatment isnt started

delayed by >3-6 hours

What is the stepwise approach to selecting antibiotic therapy?

1. determine if treatment should be based on age or predisposing condition

2. select appropriate empiric treatment

3. review culture results to streamline antibiotics

4. select appropriate duration of therapy

What is the empiric therapy: < 1 month

Ampicillin PLUS cefotaxime or Ampicillin PLUS gentamicin

What are the common pathogens for < 1 month

- GBS

- E. coli

- Listeria monocytes

- Klebsiella spp.

- Enterobacter spp.

What antibiotic covers GBS and Listeria monocytes

Ampicillin

What antibiotic covers MRSA

Vancomycin

What is the empiric therapy: 1-23 months

Vancomycin PLUS (ceftriaxone or cefotaxime)

What are the common pathogens for 1-23 months

- Streptococcus pneumoniae

- Neisseria Meningitidis

- GBS

- E. coli

- haemophilus influenza

What is the empiric therapy: 2-50 years

vancomycin PLUS (ceftriaxone or cefotaxime)

What are the common pathogens for 2-50 years

- Neisseria meningitidis

- Streptococcus pneumoniae

What is the empiric therapy: >50 years

Vancomycin PLUS Ampicillin PLUS (ceftriaxone or cefotaxime)

What are the common pathogens for > 50 years

- Streptococcus pneumoniae

- Neisseria meningitidis

- Listeria monocytes

- E. coli

- Klebsiella spp.

- Enterobacter spp.

What antibiotic(s) cover pseudomonas arg.?

- Merrem (meropenem)

- Maxipime (cefepime)

- Fortaz (ceftazidime)

What are the predisposing conditions for bacterial meningitis empiric treatments

- basilar skull fracture

- penetrating trauma

- post-neurosurgery

- CSF shunt

What is the empiric therapy: basilar skull fracture

Vancomycin PLUS (ceftriaxone or cefotaxime)

What is the empiric therapy: penetrating trauma

Vancomycin PLUS cefepime or

Vancomycin PLUS ceftazidime or

Vancomycin PLUS meropenem

What is the empiric therapy: post-neurosurgey

Vancomycin PLUS cefepime or

Vancomycin PLUS ceftazidime or

Vancomycin PLUS meropenem

What is the empiric therapy: CSF shunt

Vancomycin PLUS cefepime or

Vancomycin PLUS ceftazidime or

Vancomycin PLUS meropenem

What is the recommended dosing for vancomycin for an adult

15 mg / kg per dosing interval

max 2 g / dose or 4 g / day

What is the dosing interval of vancomycin for:

a. adults

b. pediatrics

a. q 8 hours

b. q 6 hours (clear quicker)

When dosing vancomycin, what should you round to the nearest?

250 mg

What pathogen specific therapy treats Streptococcus pneumoniae?

Sensitive: Penicillin G or Ampicillin

Resistant: Vancomycin PLUS (ceftriaxone or cefotaxime)

What pathogen specific therapy treats Neisseria meningitis?

PCN sensitive: Penicillin G or Ampicillin

PCN resistant: ceftriaxone or cefotaxime

What pathogen specific therapy treats Listeria monocytes?

Ampicillin or Penicillin G +/- Gentamicin

What pathogen specific therapy treats Pseudomonas aeruginosa?

cefepime or ceftazidime

What pathogen specific therapy treats Staphylococcus aureus?

MSSA: Nafcillin or Oxacillin

MRSA: Vancomycin

What pathogen specific therapy treats extended spectrum B-lactamase producing gram - bacilli (ESBL)

meropenem

What is the duration of treatment for Neisseria meningitidis?

7 days

What is the duration of treatment for haemophilus influenza?

7 days

What is the duration of treatment for streptococcus pneumoniae?

10-14 days

What is the duration of treatment for GBS?

14-21 days

What is the duration of treatment for Listeria monocytes?

>/= 21 days

What is the purpose of adding a steroid as an adjunctive therapy for the treatment of bacterial meningitis?

blunt effects of host inflammatory response

What are the theoretical concerns of steroids being administered with antibiotics?

steroids reduce the permeability of blood brain barrier to antibiotics

What group(s) benefit for the adjunctive therapy of steroids for bacterial meningitis?

- infant/children (>/= 6 weeks and older)

- adults

What pathogen is steroids adjunctive therapy in infants/children recommended

Haemophilus influenza

0.15 mg / kg q 6 hours for 2-4 days

What pathogen is steroids adjunctive therapy in adults recommended

Streptococcus pneumoniae

10 mg IV 1 6 hours for 2-4 days

What vaccine is recommended for Neisseria meningitidis?

MENACWY and MENB

What vaccine is recommended for H. influenza?

Hib. conjugate vaccine

What vaccine is recommended for Streptococcus pneumoniae?

Prevnar 13, 15, 20

Pneumovax 23