Flashcards in W21-L8: CNS infections Deck (20):
T/F Bacterial meningitis is a disease of the developing world?
What age group does meningitis affect most?
What is the most common cause of meningitis?
Viral infections such as enteroviruses, coxsackie, echo but are self-limiting
Which three bacteria are the commonest causes of meningitis?
H. influenza, N. meningitidis, S. pneumoniae
worldwide the most common meningococal serotype is?
Why are H. influenza, N. meningitidis, S. pneumoniae the most common?
These bacteria are best at evading the immune system, encapsulated by capsule which avoids phagocytosis
What factors affect infection?
Host factor (eg age) Pathogen factors Environmental factors
What is the process of meningitis?
￼1. Colonisation of nasopharngeal mucosa
2. Invasion of bloodstream
3. Survival and multiplication
4 Crossing of BBB
5. invasion of meninges and CNS
6. Increased permeability of BBB
7/8. Pleocytosis and increased ICP
￼￼￼￼￼￼9. Release of proinflammatory compounds
10. Neuronal Injury
What are the symptoms of meningitis?
What is the main definitive test for meningitis?
Culture from CSF
What are some other tests for meningitis?
PCR from CSF, microscopy gram stain (culture) and PCR from skin scraping
What is a normal level for WBC, protein and glucose in CSF?
WBC: Under 5 * 10^6
Glucose above 60%
Protein less than 0.4 - 1 g/L
What will bacterial meningitis show in CSF?
Raised pressure, cloudy appearance with increased WBC, positive gramstain, >1.0 g/L protein, <40% glucose
How will TB meningitis CSF differ from other bacterial CSF?
Gram stain will be ZN-positive, glucose will be less than 30%
Why is it important to measure CSF quickly?
CSF cell count rapidly decreases due to cell lysis
T/F cannot distinguish from early CSF whether a patient has bacterial or viral
What is the treatment for bacterial meningitis?
Resuscitation / Life support Fluids
What are the ￼complications of bacterial meningitis?
Highest rate is hearing loss
What are some big differences between meningitis and encephalitis?
Encephalitis is almost all viral, and also has altered conscious state (meningitis is normal conscious state)