CNS infections and meningitis

Question 1

What are the 4 lobes of the brain?

Answer 1

Frontal
Temporal
Parietal
Occipital

Question 2

How many spinal nerves are there?

Answer 2

31 pairs

Question 3

What are the 4 routes of entry?

Answer 3

Haematogenous spread (e.g. pneumococcus, meningococcus)
Direct implantation (e.g. trauma)
Local extension (e.g. from the ear)
PNS to CNS (e.g. rabies)

Question 4

What are the meningeal layers

Answer 4

Dura - Outermost
Arachnoid
Pia (Innermost)

Question 5

What is meningitis usually caused by?

Answer 5

Bacteria such as Neisseria meningitis, strep pneumo, TB, Haem influ

Fungus such as cryptococcus neoformans

Question 6

What can encephalitis be caused by?

Answer 6

Viruses such as rabies, arboviruses

amoeba

Parasites

Question 7

What can myelitis be caused by?

Answer 7

Spinal cord infections due to polio

Question 8

What can neurotoxins like Clostridium tetani and clostridium botulinum cause?

Answer 8

Rigid paralyisis and flaccid paralysis respectively

Question 9

Difference between meningitis and meningoencephalitis?

Answer 9

Meningoencephalitis is the inflammation of the meninges AND brain parenchyma

Question 10

What can meningitis be classified into?

Answer 10

Acute - Bacterial (Meningococcal, Neiseria, H.influenzae, GBS, E Coli, Listeria)
Chronic - TB, spirochetes, crytpococcus
Aseptic - Viral

Question 11

Where can Listeria be found?

Answer 11

Blue cheese, mayo

Question 12

Babies being delivered via vaginal delivery are in bigger risk of developing which kind of meningitis?

Answer 12

GBS and E Coli

So if mum is positive for GBS, give Benzylpenicilin during delivery

Question 13

What is a tell tale sign for meningococcal meningitis?

Answer 13

Purpural petichael rashes due to thrombocytopaenia as your platelet count drops. Rashes are non blanching.

Question 14

How can meningococcal meningitis present?

Answer 14

Thrombocytopaenia

Septicaemia - Hypovolaemia, coagulopathy, metab acidosis, myocardial failure

Question 15

What can be seen in a CT head of someone with TB meningitis?

Answer 15

Dilation of ventricles
Thick wall abscess
Space occupying lesions

Question 16

What are the symptoms of aseptic meningitis?

Answer 16

Headache, stiff neck and photophobia

May have non specific rash

Question 17

What are the biggest viral causes of meningitis

Answer 17

Enterovirus - Cocksackie A and B, echovirus, polio

Herpes - 1 and 2

Question 18

What is encephalitis

Answer 18

Infection of brain parenchyma - Mostly due to virus

Question 19

How do viral infections spread to cause encephalitis?

Answer 19

Mosquitoes
Lice
Ticks

Person to person

Question 20

What is the international leading cause of encephalitis?

Answer 20

West Nile virus

Question 21

What are the other leading causes of encephalitis?

Answer 21

Herpes
Enterovirus

Bacteria - Listeria

Amoeba

Toxoplasmosis

Question 22

How can you visualise brain abscess or infarcts?

Answer 22

MRI not CT

Question 23

What organisms mostly cause brain abscess?

Answer 23

Strep

Staph

Question 24

How to investigate CNS infections?

Answer 24

CSF sample
Blood culture
Throat swab
Blood PCR to detect pneumococcla and meningococcal DNA

Question 25

What should the CSF studies of a normal person look like?

Answer 25

``` Clear fluid 0-5 leukocytes No gram stain 0.15-0.4 protein >60% blood glucose levels ```

Question 26

What should the CSF studies of a person with purulent meningitis look like?

Answer 26

``` Turbid fluid 100 - 10 000 Polymorphs +ve gram stain 0.5 - 4 protein <60% blood glucose levels ```

Question 27

What should the CSF studies of a person with aseptic meningitis look like?

Answer 27

``` Clear or slightly turbid fluid 15 - 1000 Polymorphs Negative gram stain 0.5 - 1 protein >60% blood glucose levels ```

Question 28

What should the CSF studies of a person with TB meningitis look like?

Answer 28

``` Clear or slightly turbid fluid 30 - 1000 Polymorphs Negative gram stain - Scanty acid fast bacilli 1 - 6 protein <60% blood glucose levels ```

Question 29

What do stains look like in general.

Answer 29

Purple - Gram +ve Pink - Gram -ve Cocci - spherical Rods - Cuboidal

Question 30

What is a gram +ve diplococci in CSF?`

Answer 30

Pneumococcos | Strep pneumo

Question 31

What shape and gram stain in Listeria?

Answer 31

Gram +ve | Rod

Question 32

What is a gram -ve dipolococci

Answer 32

Neisseria

Question 33

What is a gram +ve cocci in clusters

Answer 33

Staph

Question 34

What is a gram +ve cocci in chains or pairs

Answer 34

Strep

Question 35

What is a gram +ve rod

Answer 35

Listeria

Question 36

What is a Ziel Nielson stain used for?

Answer 36

TB

Question 37

High pressure CSF meningitis?

Answer 37

Crytococcus Usually seen in HIV patients

Question 38

How to treat meningitis?

Answer 38

Ceftriaxone 2g iv bd If they are older than 50 or immunocompromised or you suspect Listeria, add Amoxicillin 2g iv 4 hourly

Question 39

How to treat meningo-encephalitis?

Answer 39

Ceftriaxone 2g iv bd If they are older than 50 or immunocompromised or you suspect Listeria, add Amoxicillin 2g iv 4 hourly Also give Acyclovir 10mg/kg iv tds as viruses are the leading cause of encephalitis