Infections of the Nervous System

Question 1

What is meningitis?

Answer 1

Inflammation of the brain meninges.

Question 2

What is encephalitis?

Answer 2

Inflammation of the brain parenchyma.

Question 3

What are the most common bacterial organisms in CNS infection?

Answer 3

Strep. pneumoniae
Neisseria meningitidis
Listeria monocytogenes

Question 4

What is used to treat meningitis if caused by strep. pneumoniae and neisseria meningitidis?

Answer 4

Ceftriaxone and dexamethasone.

Question 5

How are treatments for CNS infections administered?

Answer 5

Intravenously

Question 6

What is given to those with listeria monocytogenes infection?

Answer 6

Ceftriaxone, dexamethasone and amoxicillin.

Question 7

In those with history of recent travel to a country with known penicillin-resistance, what is given?

Answer 7

Vancomycin and ceftriaxone.

Question 8

In what individuals are steroids contraindicated?

Answer 8

Immunocompromised
Septic shock
Post-surgery
Steroid hypersensitivity

Question 9

What is the most common cause of viral meningitis?

Answer 9

Enterovirus

Question 10

What time of year is viral meningitis most commonly seen?

Answer 10

Late summer/autumn

Question 11

How is viral meningitis diagnosed?

Answer 11

CSF PCR
Stool culture
Throat swab

Question 12

How is viral meningitis treated?

Answer 12

Symptomatic only as the virus will be self-limiting.

Question 13

How is bacterial meningitis diagnosed?

Answer 13

Lumbar puncture

Question 14

What will a lumbar puncture show in an individual with bacterial meningitis?

Answer 14

High WBCs
High protein
Low glucose

Culture may not be positive for bacteria if antibiotics given prior to the sample being obtained.

Question 15

What are the key symptoms of meningitis?

Answer 15

Headache
Fever
Neck stiffness

Question 16

What are features of encephalitis?

Answer 16

Headache
Fever
Neck stiffness

Question 17

What conditions may precede bacterial meningitis?

Answer 17

Endocarditis
Pneumonia
UTI

Involves a haematogenous route of spread.

Question 18

What virus is commonly involved in encephalitis?

Answer 18

HSV

Question 19

What is seen on an MRI in an individual with encephalitis?

Answer 19

Hyperdense areas.

Question 20

What is meningo-encephalitis?

Answer 20

A crossover condition involving features of both meningitis and encephalitis.

Question 21

Is trauma of the cribriform plate a risk factor for strep. pneumoniae meningitis?

Answer 21

Yes

Question 22

Does a CSF pleocytosis indicate meningitis?

Answer 22

No, only confirmed when bacteria is identified.

Question 23

What does pleocytosis mean?

Answer 23

An increased WBC count.

Question 24

What individuals must get CT prior to lumbar puncture?

Answer 24

Immunosuppressed
New onset seizure
History of CNS disease
Papilloedema
Abnormal LOC

Question 25

What cells are raised in bacterial meningitis?

Answer 25

Neutrophils

Question 26

What cells are raised in viral meningitis?

Answer 26

Lymphocytes

Question 27

In relation to CSF sample glucose level, what differs between viral and bacterial meningitis?

Answer 27

Bacteria consumes glucose, meaning it will be low in bacterial meningitis. Viruses do not consume glucose, meaning it will be normal in viral meningitis.

Question 28

What is aseptic meningitis?

Answer 28

Meningitis with no pus. Can be caused by a virus, malignancy or sarcoidosis.

Question 29

In those over 60, what bacteria is a risk?

Answer 29

Listeria monocytogenes Give amoxicillin alongside ceftriaxone to cover this.

Question 30

Is meningitis a medical emergency?

Answer 30

Yes