CNS

Question 1

What is Meningitis?

Answer 1

Meningitis – infection of cerebrospinal fluid

Acute fever, headache, neck stiffness +/- rash

Fully conscious, no focal neurological signs

Usually viral but may be bacterial

Question 2

What is Encephalitis?

Answer 2

Encephalitis – infection of the brain tissue

Acute fever, headache, neck stiffness

Altered conscious level, seizures +/- focal neurological signs

Usually viral

Question 3

What is a brain abscess?

Answer 3

abscess within the brain tissue

Insidious onset of fever, headache, +/- neck stiffness

+/- Altered conscious level, seizures, focal neurological signs

Usually bacterial, may be parasitic

Question 4

What are the two most common causes of viral meningitis?

Answer 4

Enteroviruses

HSV 2

Question 5

What is Meningism?

Answer 5

Headache
Neck stiffness
Photophobia

Question 6

What clinical signs do you look for in infants with suspected meningism?

Answer 6

Look for nuchal rigidity (neck stiffness)

and bulging anterior fontanelle

Question 7

What is Kenig’s sign?

Answer 7

With hip and knee flexed to 90o, the knee cannot be extended due to pain/stiffness in the hamstrings
Positive = Meningism

Question 8

What is Brudzinski’s sign?

Answer 8

Flexing the neck causes the hips and knees to flex

Positive = Meningism

Question 9

Lumbar puncture:

What is the normal opening pressure compared to bacterial meningitis?

Answer 9

Normal =

Question 10

Lumbar puncture:

What is the normal WBC count (mm3) compared to viral and bacterial meningitis?

Answer 10

WBC normal = 0-5

Viral = 5-500 (mean 80)

Bacterial = 100-20,00 (mean 800)

Question 11

Lumbar puncture:

What is the normal protein (mg/dl) compared to viral and bacterial meningitis?

Answer 11

Protein normal = 15-50mg/dl

Viral = 30-150mg/dl

Bacterial = 100-500mg/dl

Question 12

What is Mollaret’s meningitis?

Answer 12

Recurrent aseptic meningitis

wide differential but major cause = HSV2

Question 13

What is the main cause of Viral encephalitis?

Answer 13

HSV 1

Question 14

What is the main difference between presentation of meningitis and encephalitis?

Answer 14

Encephalitis will also have:
Altered mental state
confusion/bizarre behaviour -> coma
Focal neurology eg. Seizures

Question 15

What is the treatment for Viral encephalitis?

Answer 15

High dose IV aciclovir

Question 16

What disease has the same clinical features as encephalitis? Can follow viral illness or vaccination (e.g. influenza)

Answer 16

Acute disseminated encephalomyelopathy (ADEM)

Immune-mediated CNS demyelination

Question 17

Which bacteria causes meningococcal disease and how is it treated?

Answer 17

Neisseria meningitides

• Meningitis
• Fulminant septicaemia

Ceftriaxone, cefotaxime
Penicillin

Close contacts given Rifampicin

Question 18

How do you treat meningitis caused by Haemophilus influenza and who normally gets it?

Answer 18

Ceftriaxone, cefotaxime
Ampicillin

Close contacts given Rifampicin

2months – 2 years

Question 19

How do you treat meningitis caused by Streptococcus pneumoniae and who normally gets it?

Answer 19

Ceftriaxone, cefotaxime

no prophylaxis for close contacts required

more common and severe in the elderly and immunocomprimised

Question 20

Which steroid is given with antibiotics to treat meningitis in adults?

Answer 20

Dexamethasone

Question 21

What are possible differential diagnosis for lymphocytic meningitis?

Answer 21

TB meningitis
- Rx TB antibiotics and steroids

Cryptococcal meningitis
- Rx amphotericin, flucytosine or fluconazole

Question 22

What is the most common cause of encephalitis worldwide?

Answer 22

Japanese encephalitis

One third die in the acute illness
One third left with severe long term neurological disability
One third recover

Question 23

What bacteria do brain abscesses contain?

Answer 23

Brain abscesses are often mixed (polymicrobial)
Streptococci (60-70%)
Staphylococcus aureus (10-15%)
Anaerobes
Gram negative enteric bacteria eg. E.coli, Pseudomonas spp.

Question 24

Which antibiotics can achieve therapeutic concentrations in intracranial pus?

Answer 24

ampicillin, 
penicillin, 
cefuroxime, 
cefotaxime, 
ceftazidime, 
metronidazole

Question 25

What are the possible complications of a brain abscesses?

Answer 25

Raised intracranial pressure, mass effect, coning

Rupture (usually into ventricles) causing ventriculitis

Question 26

What is Subdural empyema?

Answer 26

Infection between dura and arachnoid mata - often polymicrobial

Pathogenesis: spread of infection from sinuses (50-80%), middle ear and mastoid (10-20%)

Question 27

Which bacteria are usually responsible for Ventriculoperitoneal shunt and external ventricular drain infections?

Answer 27

coagulase-negative staphylococci

Diagnosis: CSF microscopy and culture