CNS Infections

Question 1

4 reasons why CSF infections are difficult to treat

Answer 1

Low proteins so no compliment activation, low IgG, no lymph, BBB means not all drugs given will get to where you want them

Question 2

List the main routes of infection into the CSF

Answer 2

Blood borne, parameningeal supppuration, defect in the dura eg surgery, through the cribiform plate

Question 3

Which two to features of gram +ve and -ve bacteria cause the inflammatory cascade?

Answer 3

\+ve = lipoeichoic 
-ve = endotoxins

Question 4

Describe the inflammatory cascade

Answer 4

• Bacteria in blood enters the CSF at the choroid plexus.
• Causes inflammatory mediators to be released
• This attracts Neutrophils which release O- Toxic to the endothelium
• Alters the permeability of the BBB causing oedema

Question 5

Name some inflammatory mediators

Answer 5

IL-1,6,8
NO
PAF
TNF

Question 6

Name some virulence factors of bacteria which enable them to get into your blood

Answer 6

IgA protease
Pili
Endocytosis
They can separate tight junctions

Question 7

Difference in inflammatory cascade in viral and bacterial meningitis

Answer 7

viral - mononuclear

bacteria - neutrophilic

Question 8

Symptoms of meningitis

Answer 8

Headache, photophobia, nausea, vomiting, neck and back stiffness, rash, kernigs sign (chin on neck)

Question 9

Name the two types of rash you can acquire

Answer 9

petechial and purpuric

Question 10

Symptoms of meningitis in an infant

Answer 10

strange cry, convulsions, flaccid , bulging fontanelle, fever, vomiting

Question 11

What makes diagnosing meningitis difficult

Answer 11

• General symptoms similar to other diseases e.g. sever UTI sub arachnoid haemorrhage
• Symptoms not always all present

Question 12

Describe the use of a lumbar puncture in diagnosing meningitis (2+1-)

Answer 12

Rapid test
Can distinguish between viral and bacterial
Risk of herniation (dont do if risk of increased ICP_

Question 13

When would you use a CT scan in investigating meningitis

Answer 13

when diagnosis is in doubt
with focal abnormalities
with coma or seizures as non-urgent

Question 14

Negatives to using CT scans in investigating meningitis

Answer 14

doesn’t diagnose, takes time, poor predictor of raised ICP

Question 15

Name 3 more tests you can use to investigate meningitis

Answer 15

Gram stain, PCR, Aggulation tests ( look for antigens)

Question 16

1. Nisseria meningitisis
2. Strep pnuemoniae
3. Haemophilus influenza B
4. B streptococci
5. E. Coli
6. Listeria monocytogenes

Answer 16

1. children and young adults
2. children under 2 and elderly
3. uncommon (vaccine)
4. neonates
5. neonates
6. neonates / immunocompramised

Question 17

Name the complications of meningitis

Answer 17

death, subdural collection, cerebral vein thrombus, visual/sensory/motor deficit, convulsions, 10% deafness, hydrocephalus ( increased fluid on brian )

Question 18

Describe the management of meningitis

Answer 18

antibiotics, oxygenation, anticonvulsants, prevention of hypoglycaemia and hyponatraemia, decrease intracranial pressure

Question 19

Describe Pneumococcal Meningitis

Answer 19

2nd most common, caused by Strep pnuemoniae. 30 % mortality. can also cause pneumonia and ear infection.

Question 20

Factors that predispose Pneumococcal meningitis

Answer 20

myeloma, alcohol, diabetes, IMSuppression

Question 21

Describe some features of Listeriosis Meningitis

Answer 21

Meningo-encephalitus. - effects brain stem so can cause ataxia and movement problems. mortality 20%

Question 22

Name some of the prevention and controls for Meningitis

Answer 22

Vaccines, Chemoprophylaxis

Question 23

What is Myelitis

Answer 23

Inflammation of the spinal cord

Question 24

What is Encephalitis

Answer 24

Inflammation of the brain

Question 25

Symptoms of Encephalitis

Answer 25

Irritable, altered personality, ataxia, brisk reflexes, brainstem failure = slow pupil reflexes, brain swelling = neurological signs