Neuro Emergencies: Meningitis Flashcards
Meningitis is what?
an inflammation of the arachnoid membrane, pia mater, and the intervening cerebrospinal fluid (CSF)
Meningitis
The inflammatory process extends throughout what?
the subarachnoid space around the brain and spinal cord and involves the ventricles
Epidemiology
The incidence of bacterial meningitis has decreased significantly in developed countries since the introduction of vaccines against what bacterial pathogens?
Hemophilus influenaze type B
Streptococcus pneumoniae
Neisseria miningitidis
Epidemiology
What is the most common pathogen?
S. Pneumoniae
What pathogen is emerging as the most common cause of bacterial meningitis w/ increased incidence in elderly and immunocompromised individuals?
Listeria monocytogenes
Epidemiology
Predisposing factors include?
Acute otitis media
pneumonia
sinusitis
neurosurgical procedures
immunocompromised individuals and high risk groups
Pathophysiology of Meningitis
Infectious agents can gain access to the CNS by the following routes
Hematogenous spread
Direct transmission
Retrograde venous
Neuronal pathway
Iatrogenic
Pathophysiology of Meningitis
What is Hematogenous spread?
spread from a distant infectious site
Pathophysiology of Meningitis
What is Direct transmission?
otitis media, sinusitis, trauma, congenital malformations infected tooth
Pathophysiology of Meningitis
What is Retrograde Venous transmission?
usually from nasopharynx
Pathophysiology of Meningitis
What is neuronal pathway transmission?
Olfactory and peripheral nerves
Pathophysiology of Meningitis
What is iatrogenic transmission?
LP, VPS, and cranial procedure
Pathophysiology of Meningitis
Bacteria enter the CNS via?
choroidal vessels or
in cerebral endothelial cells of the blood-CSF barrier in the posterior capillary veins
Pathophysiology of Meningitis
Upon invasion of the CSF bacteria multiply to high concentrations secondary to?
inadequate immunoglobulins and complement in CSF
Pathophysiology of Meningitis
Release of proinflammatory cytokines such as? from what cell types?
IL-1 and TNF
meningeal and endothelial cells, macrophages and microglia
Pathophysiology of Meningitis
Cytokines enhance the passage of leukocytes by inducing what?
several families of adhesion molecules that interact with corresponding receptors on leukocytes
Pathophysiology of Meningitis
Cytokines can also increase the binding affinity of leukocyte selection for?
further contributing to?
its endothelial cell receptor
neutrophils in the subarachnoid space
Pathophysiology of Meningitis
Neutrophils release what?
That disrupt what?
prostaglandins, matrix metalloproteinases and free radicals
the endothelial intracellular tight junctions and subendothelial basal lamina
Pathophysiology of Meningitis
The ultimate result from all these processes is?
Vasogenic brain edema
Cerebrovascular dysregulation
elevated ICPs
Neurologic Complications of Meningitis include?
Hydrocephalus
Coma
Seizure
Deafness
Motor Deficits
Sensory Deficits
Cognitive Deficits
Cranial Nerve Palsy
Mycotic Aneurysm formation
Thrombosis
Death
Differential Diagnosis associated with Meningitis symptoms includes?
SAH
ICH
Epidural hematoma
GBS
Arnold Chiari malformation
Intracranial neoplasm
Electroly imbalance
Hypoglycemia
Seizure
Clinical Presentation
Classic Triad?
Fever
Nuchal rigidity
AMS
Clinical Presentation
Symptoms outside of the classic triad include?
HA
Photophobia
Vomiting
Lethargy
Myalgia
Seizures
Skin manifestations
Symptoms progress hours to days
Clinical Presentation
Clinical findings are often overlooked in?
infants
obtunded patients
elderly patients w/ heart failure
elderly patients w/ pneumonia
Immunocompromised individuals
Clinical Presentation
In elderly patients neck stiffness may be difficult to evaluate d/t it possibly being caused by?
osteoarthritis
stiffness of neck muscles
Clinical Signs
Brudzinski’s Sign
Spontaneous flexion of the hips during attempted passive flexion of the neck
Clinical Signs
Kerning’s Sign
Inability or reluctance to allow full extension of the knee when the hip is flexed 90 degrees
Diagnosis
Hx will include
recent illness or sick exposure
change in mental status
focal deficit
cranial nerve palsy
Diagnosis
Physical should include?
inspection of skin
otoscopic exam
inspect oral cavity/throat
CSF otorrhea or rhinorrhea
Diagnosis
Lab Studies to check?
CBC (WBC elevated, Thrombocytopenia)
BMP (Cr, Electrolytes)
Coags
PCR
HIV
Diagnosis
50-90% of patients with bacterial meningitis have?
positive blood cultures
Diagnosis
Imaging?
Head CT
Exclude mass lesion or elevated ICP
Prevent herniation d/t CSF removal
Algorithm
With suspicion for bacterial meningitis, ask if the patient is/has
Immunocompromised
hx of CNS disease
new onset seizure
papilledema
altered consciousness
focal neruo deficit
delay in performatnce of diagnostic procedures
Algorithm
If pt has any of the following what are the next steps?
Immunocompromised
hx of CNS disease
new onset seizure
papilledema
altered consciousness
focal neruo deficit
delay in performatnce of diagnostic procedures
Blood cultures STAT
Dexamethasone (b) + empirical antimicrobial therapy(c)
Negative CT scan of the head
Perform LP
CSF findings c/w bacterial meningitis
Perform Gram Stain
Algorithm
Positive CSF Gram Stain
Yes?
No?
Yes - Dexamethasone (b) + targeted antimicrobial therapy
No - Dexamethasone (b) + empirical antimicrobial therapy
Algorithm
If pt does not have any of the following, what are the next steps?
Immunocompromised
hx of CNS disease
new onset seizure
papilledema
altered consciousness
focal neruo deficit
delay in performatnce of diagnostic procedures
BC and LP STAT
Dexamethasone (b) + empirical antimicrobial therapy
CSF findings c/w bacterial meningitis
Perform CSF gram stain
When to Order a Head CT
Immunocompromised
CNS disease
New onset seizure
Papilledema
Altered LOC
Focal Neuro deficit
LP contraindications
Coagulopathy/thrombocytopenia
Clinical signs of impending herniation
Infection at LP site
LP landmarks
L3-L4
L4-L5
L5-S1
LP
Make sure to check what?
Opening pressure
CSF analysis should include?
Color/clarity
cell count
protein
glucose
gram stain
culture
PCR and viral studies
CSF to plasma glucose is about 2/3
CSF Characteristics in Bacterial vs. Viral Meningitis
Bacterial:
Color
Cell count
Glucose
Protein
Opening pressure
cloudy
200-20,000 PMN
<40
>50-100
Markedly high
CSF Characteristics in Bacterial vs. Viral Meningitis
Viral or aseptic
Color
Cell count
Glucose
Protein
Opening pressure
clear or cloudy
100-1000PMN
Normal
>50 cells but usually less than bacterial
normal or slightly elevated
Most common organisms and treatment
Age < 1 mo
Common bacterial pathogens?
Antimicrobial therapy
Streptococcus agalactiae, Escherichia coli, Listeria monocytogenes, Klebsiella species
Ampicillin plus cefotaxime or
ampicillin plus aminoglycoside
Most common organisms and treatment
Age 1-23 mo
Common bacterial pathogens?
Antimicrobial therapy
Streptococcus pneumoniae, Neisseria meningitidis, S. Agalactiae, Haemophilus influenzae, E. coli
Vancomycin plus a third gen cephalosporin
Most common organisms and treatment
Age 2-50
Common bacterial pathogens?
Antimicrobial therapy
N. meningitidis, S pneumoniae
Vancomycin plus a third gen cephalosporin
Most common organisms and treatment
Age > 50 years
Common bacterial pathogens?
Antimicrobial therapy
S. Pneumoniae, N. meningitidis, L. monocyotogenes, aerobic gram-negative bacilli
Vancomycin plus ampicillin plus a third gen cephalosporin
Most common organisms and treatment
Head trauma (Basilar Skull Fx)
Common bacterial pathogens?
Antimicrobial therapy
S. pneumoniae, H. influenzae, group A Beta-hemolytic streptococci
Vancomycin plus a third gen cephalosporin
Most common organisms and treatment
Head Trauma (Penetrating Trauma)
Common bacterial pathogens?
Antimicrobial therapy
Staphylococcus aureus, ccoagulase-negative staphylococci (especially Stahpylococcus epidermidis), aerobic gram-negative bacilli (including Pseudomonas aeruginosa)
Vancomycin plus cefepime, vancomycin plus ceftazidime, or vancomycin plus meropenem
Most common organisms and treatment
Postneurosurgery
Common bacterial pathogens?
Antimicrobial therapy
Aerobic gram-negative bacilli (including p. aeruginosa), S. aureus, coagulase-negative staphylococci (especially S. epidermidis)
Vancomycin plus cefepime, vancomycin plus ceftazidime, or vancomycin plus meropenem
Most common organisms and treatment
CSF shunt
Common bacterial pathogens?
Antimicrobial therapy
Coagulase-negative staphylococci (especially S. epidermidis), S. aureus, aerobic gram-negative bacilli (including P. aeruginosa), Propionbacterium acnes
Vancomycin plus cefepime, vancomycin plus ceftazidime, or vancomycin plus meropenem
Antibiotics
Third Gen Cephalosporine/dose/frequency?
Ceftriaxone 2g q12hr
Cefotaxime 2g q4-6hr
Antibiotics
Glycopeptide/dose/frequency?
Vancomycin 15-20mg/kg q8-12hrs
Antibiotics
PCN/dose/frequency?
Ampicillin 2g q4hrs (in adults > 50y/o)
Antibiotics
In immunocompromised patients add what?
Instead of ceftriaxone or cefotaxime use what?
pseudomonal coverage
cefepime 2g q8hr or meropenem 2g q8hr
Antibiotics
Antiviral for HSV meningitis/dose/frequency?
Acyclovir 5-10 mg/kg TID
Antibiotics
Narrow antibiotics based on?
culture results
When can droplet precautions be discontinued?
when on antibiotics for 24 hrs
Steroids
steroid/dose/frequency/duration
dexamethasone 0.15mg/kg IV q6 hr for 2-4 days
Steroids
Reduces risk of poor neurological outcome in pt with?
Must be given when?
Believed to minimize?
S. pneumoniae
early
inflammatory cascade
