Meningitis Flashcards
What is Meningitis?
An inflammation of the membranes that surround the brain and spinal cord
Where is meningitis
Involves arachnoid, pia mater, and CSF
What causes Meningitis?
Infection Tumors stroke trauma
What is bacterial meningitis
Acute meningeal inflammation caused by bacterial infection
Generally evokes a PMN response within the CSF
What is aseptic meningitis?
Meningeal inflammation without evidence of bacteria
How does bacterial meningitis happen
Protection to the brain
* the meninges
* skull
* The blood-brain barrier
* The blood-CSF barrier
What is the issue with the BBB?
Host defense mechanisms
What is the patheogenesis?
Hematogenous, contiguous, and direct inoculation
What is the general pathogenesis of
- mucosal colonization and bacterial invasion of the host and CNS
- Bacterial replication in subarachnoid space
- inflammation/ pathophysiologic changes
- Increased intracranial pressure, cerebral edema and neuronal damage
What is the inflammatory cascade?
Cytokines are released
Cytokines promote migrations of neutrophils into the CSF
Neutrophils release PGs, matrix metalloproteinases, etc. that cause edema and swelling
What are the risk factors for meningitis?
Traumatic defects
Previous viral infeciton
Age Elderly 60 years, young children <5 years especially infants
Low socioeconomic status, crowding
Exposure to pathogens?
Recent colonization
Contact with meningitis patient
Bacterial endocarditis
IV drug use
Surgery or trauma
Splenic dysfunction
Immunosuppression
What is unique about the CSF?
Flows unidirectionally from vnetricles to subarachnoid space then down through the spinal cord.
What colour is the CSF?
Normally clear with very few WBCs; proteins that are small, and has about 50-60% of simultaneous peripheral glucose
What are the most common pathogens for infants and neonates with respect to meningitis? <1 month
What are the common pathogens for infanfs and kids 1-23 months
What is the common pathogen for 2-50 years old for meningitis?
What is the common pathogens for Surgery/trauma
What is the most common pathogens for Brain abscess?
Which pathogen is most common for meningitis? In order (4)
Which pathogen use to account for about 50% of meningitis cases?
H. Influenzae
What is the classic triad of Meningitis symptoms?
Headache, Fever, and neck stiffness
What are the other signs and symptoms of meningitis
Altered mental status
Malaise
Seizures
Vomiting
What can be evaluated in patients with suspected meningitis?
Classic triad only in 25-50%
Stick neck only present ~30% of the time
Seizures occur in 5 to 28% adults and 1/3 of kids