Bacterial Meningites Flashcards
What are the risk factors associated with bacterial meningites?
- Head trauma
- CNS shunts
- Neurosurgical patients
- CSF fistula/leaks
- Local infections: sinusitis, otitis media, pharyngitis
- Immunosuppressed
- Splenectomized patients
- Congenital defects
Describe the pathophysiology of bacterial meningites
Risk factors predispose patients of infection and colonization by bacteria causing meningites
Bacteria then gains entry by various mechanisms:
1. Invasion of mucosal surface then hematogenous spread to brain
2. Spread from para-meningeal focus
3. Penetrating head trauma
4. Anatomic defect in meninges
5. Previous neurosurgical procedures
Bacteria enter CNS and colonize the meninges
Describe the clinical presentations of bacterial meninges
Fever and chills
Traid of headache, backache and neck rigidity
Mental status change
Photophobia
Nausea and vomiting
Petechiae and purpura
Infants having poor feeding habits
What are some physical signs of patients with bacterial meningitis?
Kernig sign
Brudzinski sign
Bulging fontane
How is bacterial meningitis diagnosed?
Lumbar puncture to check for CSF composition, CSF gram stain and culture and CSF PCR
What are the components of CSF to look out for in diagnosing bacterial meningitis?
Glucose
Protein
WBC
Physical observation of CSF
What is the CSF composition in one with bacterial meningitis?
Glucose low
Protein raised
WBC raised with predominant neutrophils
Turbid fluid
What is the CSF composition in one with viral meningitis?
Glucose: normal to slightly low
Protein: Normal to mildly raised
WBC: Raised with predominant leukocytes
Clear fluid
Is radiology often done for bacterial meningitis?
No. Usually done to evaluate differential diagnosis and complications
Why is a radiology test done before the lumbar puncture?
Concerns of brain shift due to mass lesions and also potential risk of brain hernia during lumbar puncture
What are the different age groups in bacterial meningitis?
Neonates
Infants and children
Children and adults
Adults > 50y
What are the type of pathogens identified for bacterial meninigitis in neonates?
Group B Streptococcus
E.Coli
Listeria monocytogenes
What are the type of pathogens identified for bacterial meninigitis in infants and children (1-23 months old)?
Group B Streptococcus
E.coli
Neisseria meningitidis
S.Pneumoniae
What are the type of pathogens identified for bacterial meninigitis in children and adults (2-50 years)?
Neisseria meningitidis
S.Pneumoniae
What are the type of pathogens identified for bacterial meninigitis in adults > 50 y?
Neisseria meningitidis
S.Pneumoniae
Listeria monocytogenes
Other gram negatives including E.coli, Klebsiella