Flashcards in CNS Infections - Cellular Pathogens Deck (60):
What is meningitis?
Inflammation of meninges
What is encephalitis?
Inflammation of brain
What is myelitis?
Inflammation of spinal cord
What is neuritis?
Inflammation of nerves
What is a brain abscess?
Pus in brain
What is a subdural empyema?
Pus in subdural space
What is an epidural abscess?
Pus in epidural space
Where are most cases of bacterial meningitis found?
96% in less developed countries
What is the mortality rate of bacterial meningitis globally?
How many people have neurological sequalae after bacterial meningitis?
Half of survivors
Who is meningococcal disease most common in?
Children under age of 5
How does the likelihood of death from bacterial meningitis change over different age groups?
More likely as you get older
What are the causes of meningitis?
What is aseptic meningitis?
- Didn't grow bacteria
- Caused by something else
What is the most common cause of meningitis?
What are the most common viral causes of meningitis?
What are other infectious causes of meningitis?
What are some non-infectious causes of meningitis?
- IV Ig
- Connective tissue disorders
Does viral meningitis usually need treatment? Why?
Doesn't usually need treatment because
- Don't get neurological sequelae
What are the most common causes of bacterial meningitis?
Who gets infected with the three most common causes of bacterial meningitis?
What are the most common types of N meningitidis in Australia?
B and C
Which type of N meningitidis is the most common killer of people and especially children worldwide?
Which type of H influenzae is most common in Australia?
Where are the three most common causes of bacterial meningitis usually found?
Which bacteria additionally cause bacterial meningitis in neonates and infants under the age of three months?
E coli and other Gram negative rods
Group B Streptococcus
Where are the bacteria that especially infect neonates and young infants found?
In birth canal of mother
Which bacteria don't usually cause bacterial meningitis?
Streptococcus pyogenes (group A)
What are the host factors that predispose a person to bacterial meningitis?
Recent respiratory infection
What are the pathogen factors that predispose a person to bacterial meningitis?
What are the environmental factors that predispose a person to bacterial meningitis?
Attendance at daycare
Sharing food, drink, and dummies
What are the steps in the development of bacterial meningitis?
1. Colonisation of nasopharyngeal mucosa
2. Invasion of bloodstream > bacteraemia
3. Survival and multiplication > septicaemia
4. Crossing of BBB
5. Invasion of meninges and CNS
6. Increased permeability of BBB
8. Increased intracranial pressure
9. Release of pro-inflammatory cytokines
10. Neuronal injury
What causes neuronal injury in bacterial meningitis?
What are the non-specific symptoms and signs of meningitis?
What are more specific signs of meningitis?
Altered mental state
What is meningococcal disease often associated with?
Petechial or purpuric rash
How do you test if a rash is purpuric?
Put glass against rash > doesn't blanch
What are the normal values of CSF?
Pressure: 60% blood
Do normal CSF values change with age?
What does the CSF look like with viral meningitis?
Negative Gram stain
What does the CSF look like with bacterial meningitis?
Hugely increased WCC
Positive Gram stain
What does the CSF look like with TB meningitis?
ZN positive stain
When don't you perform a lumbar puncture?
Infection at site of lumbar puncture
What happens to the CSF sample if it isn't sent off to the lab immediately?
Cells start to lyse > WCC and glucose rapidly decrease
Can normal CSF results exclude meningitis?
Does pre-treatment with antibiotics change the WCC in CSF?
What is the treatment for bacterial meningitis?
What are the antibiotics used for the treatment of bacterial meningitis?
IV 3rd generation cephalosporin
- Eg: cefotaxime/ceftriaxone
For neonates and infants under 3 months, add
- IV penicillin
- IV gentamicin
Why is the family of the patient also treated?
Because family at increased risk of infection, especially if bacteria N meningitidis
What antibiotic is given to contacts for prophylaxis?
Which bacteria is associated with the worst complications?
What is the most common neurological sequelae of bacterial meningitis?
Why are steroids used in the treatment of bacterial meningitis?
Suppress immune response that causes damage
What is the state of consciousness in a person with meningitis?
What are the causes of encephalitis?
Almost always viral
What is the most common cause of viral encephalitis?
What are the symptoms of encephalitis?
Altered conscious state
What is added to the treatment if encephalitis is suspected?
Why is acyclovir added to treatment of bacterial meningitis if encephalitis is suspected?
People can have meningoencephalitis