Meningitis Flashcards
(53 cards)
What is meningitis?
Inflammation of the meninges
What are the different causes of meningitis?
1) Acute bacterial
2) Chronic bacterial e.g. TB, lyme disease
3) Viral e.g. mumps, HSV, enterovirus
4) Spirochaetal e.g. due to syphilis
5) Protozoal
6) Non-infectious e.g. autoimmune or medication
7) Fungal e.g. cryptococcus esp. in HIV
Which bacteria causes pneumococcus meningitis?
S.pneumoniae
Which bacteria causes meningococcus meningitis?
Neisseria meningitidis (meningococcus)
How would you treat viral meningitis?
Supportively (milder form of disease)
What is the pathogenesis of acute bacterial meningitis?
- Organisms usually enter via the bloodstream
- Direct spread of e.g. sinusitis or otitis media
What does the cause of acute bacterial meningitis depend on?
1) Community or hospital acquired
2) Age, immune suppression
3) Contact with another case
5) Travel and relevant exposures
When does nosocomial meningitis generally occur?
Post neurosurgery
What type of meningitis is common in 20-40 year olds?
Viral meningitis
What is the most common cause of pneumonia globally?
S.pneumoniae
Which type of meningitis causing bacteria can be acquired from the maternal reproductive system in utero in neonates/the most common cause in newborns (up to 3 months)?
Streptococcus agalactiae (group B strep)
What is the most common cause of acute bacterial meningitis in young people < 25
N.meningitidis
What is the mortality of acute bacterial meningitis?
10-30%
What are complications of acute bacterial meningitis?
1) Hearing loss esp. with S.pneumoniae
2) Limb loss
3) Subdural empyema
4) Hydrocephalus (bulging fontanelle)
5) Seizures
6) Neurocognitive dysfunction e.g. difficulties sleeping
What are the classic symptoms and signs in meningitis?
- Fever (shivering)
- Altered mental state
- Neck stiffness
- Headache
- Nausea
- Vomiting
- Lethargy/irritability/reduced feeding
- Photophobia
What is the classic meningitis triad in ~50% of patients?
Fever + altered mental state + neck stiffness
What to almost all meningitis patients present with?
At least 2 of fever, altered mental state, neck stiffness and headache
Can clinical features distinguish between viral and bacterial meningitis?
No
What is meningism?
Fever + headache + neck stiffness
What symptom is more likely in older than younger people?
Altered consciousness
What symptom is more likely in younger people than older people?
Neck stiffness
What is the gold standard of meningitis diagnosis?
Examine CSF via a lumbar puncture
What are diagnostic features of meningitis CSF?
1) Elevated opening pressure (may not be in viral)
2) Elevated white cells (and red cells) - may be low in early infection (low = worse prognosis)
3) Elevated protein
4) Reduced glucose compared to plasma (used up and altered metabolism of glucose in CSF)
5) CSF lactate (useful to determine if bacterial before abx)
6) CSF gram stain (to determine bacteria, before abx)
7) CSF bacterial culture - if isolated means that is cause, before abx
8) PCR - useful if abx given can identify DNA of dead bacteria
What would be the appearance of the CSF in bacterial (not viral) meningitis?
Turbid - cloudy, opaque, thick due to inflammatory cells (TB = clear or cloudy)