Meningitis Flashcards
Bacterial meningitis causes how many cases a year?
4-6 cases per 100,000 people
80% of meningitis is caused by which bacteria?
streptococcus pneumoniae and neisseria meningits
If a patient has a gram-negative bacillary meningitis, they have a 60 % chance of developing what complications?
irreversible complications
What are examples of gram-negative bacillary meningitis?
pseudomonas aeruginosa or enterobacter species like E.coli
What different pathogen types can cause meningitis?
bacteria, viral, fungal, parasitic, and mycobacterium (tuberculosis)
What are bacteria pathogens that cause meningitis?
streptococcus pneumoniae, neisseria meningitidis, haemophilus influenzae, and monocytogenes
What are viral pathogens that can cause meningitis?
enterovirus, arbovirus, and herpes
What are parasitic pathogens that can cause meningitis?
naeglaria species and acanthamoeba species
What are fungal pathogens that can cause meningitis?
cyroticiccus neoformans
What is the most common causative agent of meningitis in infants younger then 2 years of age?
Group B streptococcus (GBS)
Why is GBS the most common in infants 2 years of age?
GBS are normal flora of the birth canal and can be transmitted to infants during childbirth
What is the most common causative agent of meningitis in children 2-10 years of age?
streptococcus pneumoniae
What is the most common cause of meningitis in adolescents 11-17 years of age as well as young adults 18-34?
neisseria meningitidis
What is the most common causative agent of meningitis in adults 35 and older?
streptococcus pneumoniae
What are the 3 layers of the meninges?
dura mater, arachnoid, and pia matter
What is the most external layer that lays against the skull bone?
dura mater
What is the most internal layer that cover the brain?
pia mater
When you give an antibiotic for meningitis, what must it be able to penetrate?
it must penetrate into the Cerebrospinal fluid to reach the meninges
What is the different pathophysiology of meningitis?
mucosal colonization, intravascular survival, meningeal invasion, subarachnoid space invasion and blood brain barrier disruption?
What is the most common cause of meningitis?
mucosal colonization
To cause meningitis, a pathogen must be able to ?
Pathogens must have fimbriae to be able to attach to mucosal layers and “climb” into the meninges
Which pathogens possess fimbriae?
H. influenzae and N. meningitidis
Which pathogen is a polysaccharide capsule?
S. pneumoniae
What is intravascular survival?
It can occur from mucosal colonization and it is where bacterial can translocate from one region to the blood and CSF
When would you see meningeal invasion, subarachnoid space invasion or BBB disruption?
It occurs with more invasive bacteria due to inflammation
What happens when bacteria invade the meninges?
inflammation occurs which leads to the disruption of the BBB
The cells that comprise the BBB have very tight junctions between them making them?
the cells make it nearly impermeable to almost everything
If just one bacterium crosses the BBB, it can cause?
inflammation or disruption of the BBB, which allows more bacteria to cross over and infect the meninges resulting in severe disease
What are clinical presentations of meningitis in adults?
Headache Fever Stiff Neck (nuchal rigidity) Photophobia Altered mental status Obtundation (altered consciousness) Seizures Vomiting
What are clinical presentations of meningitis in infants?
Irritability Altered sleep Vomiting High-pitched cry Decreased oral intake
What are clinical presentations of meningitis in children?
Lethargy
Confusion
Somnolence
What are clinical signs of meningitis?
Brudzinski’s neck sign
Kernig’s sign
Babinski sign
What is the Brudsinski’s neck sign?
- Flexion of the neck causes hip and knee flexion (positive or negative)
- Positive result is a potential sign of problems with meninges
What is Kernig’s sign?
-Inability to straighten the leg (knee always stays flexed) when hip is flexed to 90 degrees
What is the Babinski sign?
- A pen is strobed on either top or bottom of foot, and toes should go down
- If toes curl upward, it is a positive sign
How much CSF should be in infants, children, and adults?
- Infants, 50 mL
- Children, 100 mL
- Adults, 150 mL
Cerebrospinal fluid is obtained through what?
Spinal Tap (or Lumbar Puncture)
When is a lumbar puncture indicated?
It is indicated for all patients who are suspected of having meningitis to determine if they have meningitis and if the causative agent is bacterial, viral, fungal, or parasite
What is the appearance of CSF?
- Normal clear
- Sterile
- 50-60% serum glucose
- pH 7.4
- Less than 5 WBC/mm3
What is CSP levels used to diagnose bacterial meningitis?
- WBC 1000-5000
- Neutrophil >80%
- Protein 100-500, bacteria eat sugar and spit out proteins
- Glucose <40 CSF/Serum ratio <0.4
What is important to not in diabetic patients in regards to glucose and protein levels?
Elevated glucose levels should NOT rule out a diagnosis of bacterial meningitis especially if protein levels are elevated
What are diagnostic methods of meningitis?
- CSF evaluation
- Enzyme immunoassay (EIA)
- Polymerase Chain Reaction (PCR)
How is CSF used as a diagnostic method?
Following analysis, a CSF will be sent for a gram stain
How is enzyme immunoassay used as a diagnostic method?
It is used for unusual pathogens that may not grow in culture