10. Meninges And Subarachnoid Haemorrhage

Question 1

What causes an extradural haemorrhage?

Answer 1

Trauma to middle meningeal artery

Question 2

What is the specific feature of extradural haemorrhage?

Answer 2

Loss of consciousness, consciousness, loss of consciousness - lucid internal

Question 3

What blood vessels are responsible for subdural bled?

Answer 3

Bridging veins

Question 4

What is CSF formed by?

Answer 4

Choroid plexus

Question 5

Where does CSF flow?

Answer 5

Lateral ventricles
To third ventricle
To fourth ventricle via aqueduct of sylvius
To subarachnoid space via median and lateral apertures

Question 6

How does subarachnoid haemorrhage present?

Answer 6

Thunderclap headache
Dizziness
Orbital pain
Diplopia 
Visual loss

Question 7

What are subarachnoid haemorrhages usually cause by?

Answer 7

Rupture of saccular aneurysms (berry aneurysms)

Question 8

What are the risk factors of aneurysms?

Answer 8

Same as CVS

Excessive alcohol intake

Question 9

What can happen after a subarachnoid haemorrhage?

Answer 9

Microthrombi which can occlude smaller distal arteries
Vasoconstriction from CSF irritant
Cerebral oedema
Sympathetic activation - myocardial damage
Early rebelling
Acute hydrocephalus
Global cerebral ischaemia

Question 10

What does the CSF show in subarachnoid haemorrhage?

Answer 10

Yellow tinge after centrifuging - xanthochromia

High protein

Question 11

What treatment is given to subarachnoid haemorrhage patients?

Answer 11

CCB - nimodipine (to prevent vasospasm and secondary ischaemia)
Operate on patients within 48hrs to prevent re-bleeding
Clipping - clamping neck of aneurysm
Coiling - insertion of wire into aneurysm

Question 12

How does meningitis present?

Answer 12

Triad: headache, neck stiffness, photophobia
Others: flu like, joint pains, rash, reduced GCS/seizures
Babies: inconsolable crying, reduced feeds, floppy, bulging fontanelle

Question 13

When is a rash most common in meningitis?

Answer 13

Meningococcal meningitis

Question 14

What are the common bacterial causes of meningitis?

Answer 14

Streptococcus pneumonia - most common
Neisseria meningitides
Haemophilus influenza

Question 15

What are the risk factors for meningitis?

Answer 15

Young and old
Crowding
Immune problems
Cochlea implants

Question 16

How can bacteria reach the CNS?

Answer 16

Colonisation of nasopharynx, ascent of bacteria through Eustachian tube, prolonged infection in this area can lead to spread to CSF
Colonisation of nasopharynx, seeding to lower resp tract, lung inflammation so bacteria enter blood, invasion of CSF via capillaries
Neonates can get pathogens from maternal source

Question 17

What are the complications of meningitis?

Answer 17

Septic shock
Disseminated intravascular coagulation
Coma
Seizures
Hearing loss
Hydrocephalus
Focal paralysis

Question 18

What is the first line investigation in meningitis?

Answer 18

Lumbar puncture

Question 19

What does CSF show in untreated bacteria meningitis?

Answer 19

Cloudy - lots of white cells
Elevated protein
Low glucose
Positive gram stain

Question 20

What does CSF show in viral meningitis?

Answer 20

Clear or cloudy
Normal or raised protein
Normal glucose

Question 21

When can performing a lumbar puncture in meningitis be bad?

Answer 21

If there is a raised ICP, can cause brain herniation as there is a sudden decrease in pressure
If there are signs of increased ICP or evident on CT, lumbar puncture may not be safe

Question 22

What is the treatment for meningitis?

Answer 22

Empirical antibiotics - vancomycin + ceftriaxone/cefotaxime
Supportive therapy - intubation if altered consciousness, fluids if shocked, oxygen
Dexamethasone to prevent hearing loss
If viral, aciclovir