Subarachnoid haemorrhage

Question 1

What is it

Answer 1

Spontaneous bleeding into the subarachnoid space

often catastrophic

Question 2

Incidence

Answer 2

9/100000/yr

Question 3

Typical age affected

Answer 3

35-65

Question 4

Management

Answer 4

Any known SAH immediately refer to neurosurgery
Re-examine CNS often - chart BP, pupils and GCS (repeat CT if deteriorating)
Maintain cerebral perfusion by keeping well hydrated
Reduce vasospasm by NIMODIPINE (Ca2+ antagonist)
Surgery

Question 5

Where is the subarachnoid space

Answer 5

Between arachnoid layer of meninges and pia mater

Question 6

What is the most common cause of rupture

Answer 6

Berry aneurysm

Question 7

Aetiology

Answer 7

Rupture of saccular aneurysms (80%) e.g. berry aneurysm
Atriovenous malformation (10%)
No cause found (5%)
Others e.g. bleeding disorder, acute bacterial meningitis, mycotic aneurysms (endocarditis) etc

Question 8

What is berry aneurysm rupture

Answer 8

Rupture of the junction of the posterior communicating artery with the internal carotid or of the anterior communicating artery with the anterior cerebral artery - in the circle of Willis

Question 9

What % of rupture of saccular aneurysms are multiple

Answer 9

15%

Question 10

Describe what is meant by atriovenous malformation

Answer 10

Vascular developmental malformation often with a fistula between arterial and venous systems causing high flow through the AVM and high-pressure arterialisation of draining veins

Question 11

Risk factors

Answer 11

Hypertension
Known aneurysm
Family history
Smoking, bleeding disorders, post-menopausal decreased oestrogen
Disease that predispose to aneurysm:
Polycystic kidney disease, Coarctation of aorta, Ehlers Danlos syndrome

Question 12

Pathophysiology

Answer 12

Most common cause is ruptured aneurysm which leads to tissue ischaemia (since less blood can reach tissue) as well as rapid raised ICP as the blood (fast flowing since arterial), acts like a space-occupying lesion, puts pressure on the brain, resulting in deficits if not resolved quickly

Question 13

Clinical presentation

Answer 13

SUDDEN onset - severe occipital headache - thunderclap (like being kicked in the head)
Followed by vomiting, collapse, seizures and coma

Question 14

Other features of clinical presentation

Answer 14

Dpressed level of consciousness
Coma/drowsiness may last for days
Neck stiffness
Kernig's sign and Brudzinski's sign
Retinal and vitreous bleeds
Papilloedema (dilated optic disc)
Vision loss or diplopia (double vision)
(High BP as a reflex to following haemorrhage)

Question 15

What is Kernig’s sign and Brudzinski’s sign

Answer 15

Kernig’s sign = unable to extend patients leg at the knee when the thigh is flexed
Brudzinski’s sign = when patients neck is flexed by doctor, patient will flex their hips & knees

Question 16

Differential diagnosis

Answer 16

Differentiate from migraine
In primary care only 25% of those with severe thunderclap headache have SAH
Meningitis
Intracerebral bleeds
Cortical vein thrombosis
50-60% no cause is found for headache

Question 17

How would you differentiate this from a migraine

Answer 17

Short time to maximal headache intensity and presence of neck stiffness usually indicate SAH

Question 18

Diagnosis - gold standard

Answer 18

Head CT
Detects >90% of SAH within 1st 48 hours
Seen as a star shaped lesion due to blood filling in gyro patterns around the brain and ventricles

Question 19

Diagnosis other than Head CT

Answer 19

Arterial blood gas to exclude hypoxia
CT angiography if aneurysm confirmed to see extent
Lumbar puncture

Question 20

When would you do a lumbar puncture for diagnosis

Answer 20

When CT normal but SAH still suspected

Question 21

How does lumbar puncture detect SAH

Answer 21

CSF in SAH is uniformly bloody early on and becomes xanthochromic (yellow) after several hours due to breakdown products of Hb (bilirubin)
Xanthochromia presence CONFIRMS SAH

Question 22

Complications

Answer 22

Rebleeding
Cerebral ischaemia due to vasospasm - can result in permenant deficit
Hydrocephalus due to blockage of arachnoid granulations - requires ventricular or lumbar drain
Hyponatraemia

Question 23

Treatment

Answer 23

Refer ALL PROVED SAH to neuro-surgeon immediately
Maintain cerebral perfusion - hydrate with IV fluids (aim for BP <160mmHg)
Ca2+ blocker e.g. Nimodipine to reduce vasospasm and morbidity
Endovascular coiling (promotes thrombosis and ablation of aneurysm)
Surgery - intracranial stents and balloon remodelling for wide-necked aneurysms

Question 24

What is 1st line treatment where angiography shows aneurysm

Answer 24

Endovascular coiling

Question 25

What % die in hospital

Answer 25

50%