W21-L8: CNS infections

Question 1

T/F Bacterial meningitis is a disease of the developing world?

Answer 1

True

Question 2

What age group does meningitis affect most?

Answer 2

Young children

Question 3

What is the most common cause of meningitis?

Answer 3

Viral infections such as enteroviruses, coxsackie, echo but are self-limiting

Question 4

Which three bacteria are the commonest causes of meningitis?

Answer 4

H. influenza, N. meningitidis, S. pneumoniae

Question 5

worldwide the most common meningococal serotype is?

Answer 5

A

Question 6

Why are H. influenza, N. meningitidis, S. pneumoniae the most common?

Answer 6

These bacteria are best at evading the immune system, encapsulated by capsule which avoids phagocytosis

Question 7

What factors affect infection?

Answer 7

Exposure
Host factor (eg age) Pathogen factors Environmental factors

Question 8

What is the process of meningitis?

Answer 8

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

Question 9

What are the symptoms of meningitis?

Answer 9

Fever
Vomitting/nausea
Irritable
Refusing drink/food
Headache
Stiff neck
Bulging fontanelle
Photophobia

Question 10

What is the main definitive test for meningitis?

Answer 10

Culture from CSF

Question 11

What are some other tests for meningitis?

Answer 11

PCR from CSF, microscopy gram stain (culture) and PCR from skin scraping

Question 12

What is a normal level for WBC, protein and glucose in CSF?

Answer 12

WBC: Under 5 * 10^6
Glucose above 60%
Protein less than 0.4 - 1 g/L

Question 13

What will bacterial meningitis show in CSF?

Answer 13

Raised pressure, cloudy appearance with increased WBC, positive gramstain, >1.0 g/L protein, <40% glucose

Question 14

How will TB meningitis CSF differ from other bacterial CSF?

Answer 14

Gram stain will be ZN-positive, glucose will be less than 30%

Question 15

Why is it important to measure CSF quickly?

Answer 15

CSF cell count rapidly decreases due to cell lysis

Question 16

T/F cannot distinguish from early CSF whether a patient has bacterial or viral

Answer 16

True

Question 17

What is the treatment for bacterial meningitis?

Answer 17

Resuscitation / Life support Fluids
Antibiotics
Steroids

Question 18

What are the complications of bacterial meningitis?

Answer 18

Highest rate is hearing loss

Question 19

What are some big differences between meningitis and encephalitis?

Answer 19

Encephalitis is almost all viral, and also has altered conscious state (meningitis is normal conscious state)

Question 20

If both meningitis and encephalitis are present how do you treat?

Answer 20

Treat HSV with axcilivir