SAH

Question 1

def

Answer 1

bleeding into the subarachnoid space (between arachnoid mater and pia mater)

Question 2

aetiology

Answer 2

saccular aneurysm rupture is commonest (80%)
arteriovenous malformations (15%)

Question 3

epi

Answer 3

common

often affects middle aged people

Question 4

associations/risk factors

Answer 4

smoking + alcohol
HTN
polycystic kidney disease (associated with saccular aneurysms)

Question 5

what are berry aneurysms

Answer 5

AKA saccular aneurysms

increase risk of SAH

Question 6

where are berry aneursyms commonly found

Answer 6

junction of posterior communicating with internal carotid

junction of anterior communicating with anterior cerebral artery

Question 7

history

Answer 7

sudden severe headache ‘kick in the back of the head’
symptoms of meningism (neck stiffness + photophobia)
reduced consciousness

Question 8

examination

Answer 8

signs of meningism (neck stiffness, photophobia, headache)
kernigs sign positive
focal neurological signs
-aneurysms may press on CNs and produce III or VI nerve palsies

Question 9

what is the meningism triad

Answer 9

neck stiffness (nuchal rigidity)
photophobia
headache

Question 10

what is kernigs sign and how long does it take to develop

Answer 10

resistance or pain on knee extension when the hip is flexed

takes 6hrs to develop

Question 11

what are the DDx for SAH

Answer 11

meningitis

migraine

Question 12

investigations

Answer 12

CT head is first line (detects 90% of SAH)
LP is second line (if CT head negative)
-CSF is initially uniformly bloody and later xanthocromic (yellow colour) due to breakdown of Hb
-finding yellow CSF confirms SAH, and shows LP was not just a ‘bloody tap’ (hit a blood vessel)

Question 13

what are the components of the GCS

Answer 13

Eyes (4)
Verbal (5)
Motor (6)

Question 14

what are the features of the eye component of GCS

Answer 14

eyes open:

spontaneously 4
to speech 3
to pain 2
none 1

Question 15

what are features of the verbal component of GCS

Answer 15

speech is:

oreinted 5
confused 4
inappropriate 3
incomprehensible 2
none 1

Question 16

what are features of the motor component of GCS

Answer 16

obeys commands 6
localising pain 5
withdrawal to pain 4
abnormal flexion to pain 3
extending to pain 2
none 1