CNS Infections

Question 1

What is meningitis?

Answer 1

Infection of the meninges

Question 2

Describe the route of infection for meningitis?

Answer 2

Microorganisms reach the meninges either by direct extension from the ears, nasopharynx, cranial injury or congenital meningeal defect or by blood stream spread

Question 3

2 most common causes of meningitis?

Answer 3

Strep pneumonia and neisseria meningitidis

strep pneuomnia is most common

Question 4

Describe neisseria meningitidis?

Answer 4

Gram negative cocci in pairs

Question 5

Describe how neisseria meningitidis probably causes meningitis?

Answer 5

Can be found in the throats of healthy carriers
The bacteria probably gain access to the meninges through the bloodstream
Symptoms are due to the bacteria endotoxin

Question 6

Neisseria meningitidis is more common in ________ and can be _________

Answer 6

young children and adults

responsible for outbreaks

Question 7

Describe the capsular groups of neisseria meningitidis and the vaccine?

Answer 7

There are 12 capsular groups there is currently a vaccine for ACWY

Question 8

What causes the classic non blanching rash of meningitis?

Answer 8

Neisseria meningitidis infection that gets in the blood

Question 9

Neisseria meningitidis is also referred to as?

Answer 9

meningococcus

Question 10

Describe strep pneumonia?

Answer 10

Alpha haemolytic gram positive cocci in chains

Question 11

Who has a higher risk of developing strep pneumonia meningitis?

Answer 11

Those with diabetes, skull fractures of cochlear implants

Question 12

Describe haemophilus influenza meningitis?

Answer 12

Now a vaccine for HiB so not as common

Question 13

Describe listeria moncytogenes?

Answer 13

gram positive bacilli

Question 14

Who does listeria monocytogenes tend to cause meningitis in?

Answer 14

neonates, elderly, immunosuppressed, particularly those with malignancy

Question 15

Give an example of an organism that can cause chronic meningitis?

Answer 15

Tuberculosis

Question 16

Describe some signs and symptoms of meningitis?

Answer 16

headache
neck stiffness
fever
photophobia
vomiting 
intense malaise
petechial rash in meningococcal infection

Question 17

Describe treatment of meningitis?

Answer 17

• ceftriaxone IV 2g bd (if penicillin allergic give chloramphenicol instead) + dexamethasone just before or started with antibiotics
• if listeria is suspected (it should be suspected in those 60 or over or immunocompromised which includes alcoholics and diabetics) should give amoxicillin IV
• if recent travel (within 6 months) to a country on list of high rates of penicillin resistance then add vancomycin too

Question 18

Who should listeria be suspected then and therefore be treated with amoxicillin as well as ceftriaxone?

Answer 18

those 60 or over

those immunocompromised which includes diabetics and alcoholics

Question 19

Does ceftriaxone cover listeria?

Answer 19

NO

so if suspected must give amoxicillin

Question 20

Describe the course of viral meningitis?

Answer 20

This is almost always benign self limiting condition lasting 4-10 days.
Headache may follow for some months.
There are no serious sequelae unless an encephalitis is present.

Question 21

Describe 4 tests for suspected meningitis?

Answer 21

Blood cultures
Throat swab for culture
CSF sample (although cant do LP / must be careful if high ICP)
Might do PCR

Question 22

This describes the typical CSF findings for?

10^1-10^3 cell count predominantly lymphocytes
Gram staining neg
Normal or slightly high protein
Normal glucose

Answer 22

Viral meningitis

Question 23

Describe CSF findings for viral meningitis?

Answer 23

10^1-10^3 cell count predominantly lymphocytes
Gram staining neg
Normal or slightly high protein
Normal glucose

Question 24

Describe CSF findings for bacterial meningitis?

Answer 24

10^1-10^4 cell count predominantly neutrophils
Positive gram staining
High protein count
Less than 70% of blood glucose (not sure if bacterial influenced or because immune cells using glucose as fuel)

Question 25

This describes the typical CSF findings for?

10^1-10^4 cell count predominantly neutrophils
Positive gram staining
High protein count
Less than 70% of blood glucose

Answer 25

bacterial meningitis

Question 26

This describes the typical CSF findings for?

10^1-10^3 cell count predominantly lymphocytes
Positive or negative gram staining
High or very high protein
Less than 60% blood glucose

Answer 26

Tuberculosis meningitis

Question 27

Describe the typical CSF findings for tuberculosis meningitis?

Answer 27

10^1-10^3 cell count predominantly lymphocytes
Positive or negative gram staining
High or very high protein
Less than 60% blood glucose

Question 28

What are the public health reporting requirements in terms of meningitis?

Answer 28

Must report every suspected case of bacterial meningitis

May do tracing and give prophylactic treatment to contacts

Question 29

What is encephalitis?

Answer 29

Acute inflammation of the brain parenchyma usually viral

Question 30

Describe causes of encephalitis?

Answer 30

Lots of causative viruses, varies depending on countries
Most common in UK is herpes simplex
Other causes now with vaccines includes measles, mumps, rubella
Other common causes include varicella zoster virus, enteroviruses and adenovirus

Question 31

Describe signs and symptoms of encephalitis?

Answer 31

insidious onset
personality and behavioural changes
confusion and speech disturbance 
reduced consciousness 
coma
focal neurological deficits
seizures

Question 32

Describe investigations for encephalitis and what they might show?

Answer 32

MRI shows areas of inflammation and swelling (bright areas), raised ICP and midline shift may occur
EEG shows periodic sharp and slow wave complexes
CSF shows elevated lymphocyte count
Viral detection by CSF PCR can detect HSV or VZV

Question 33

Describe management of viral encephalitis?

Answer 33

Suspected HSV and VZV encephalitis is treated immediately with IV acyclovir even before investigation results are available
Early treatment significantly reduces both mortality and long term neurological damage in survivors
Seizures are treated with anticonvulsants

Question 34

Describe complications of encephalitis?

Answer 34

long term complications are common and include memory impairment, personality change and epilepsy

Question 35

Describe what meningo-encephalitis is?

Answer 35

inflammation of both the brain parenchyma and the meninges