Subarachnoid Haemorrhage

Question 1

What is a subarachnoid haemorrhage?

Answer 1

arterial haemorrhage into the subarachnoid space

Question 2

Explain the aetiology of subarachnoid haemorrhage

Answer 2

85%: rupture of a saccular aneurysm at the base of the brain (Circle of Willis- Berry aneurysms)
10%: perimesencephalic haemorrhage
5%: arteriovenous malformations, bleeding diathesis, vertebral artery dissection

Question 3

What are saccular aneurysms associated with?

Answer 3

Polycystic kidney disease
Marfan’s syndrome
Ehlers-Danlos syndrome

Question 4

List 3 risk factors for SAH

Answer 4

HTN
Smoking
Excess alcohol intake

Question 5

Describe the epidemiology of subarachnoid haemorrhage

Answer 5

Incidence: 10/100,000

Peak incidence: 50s

Question 6

List 5 symptoms of subarachnoid haemorrhage

Answer 6

Sudden-onset worst headache ever (Hit in the back of the head with baseball bat/ Thunderclap)
N+V 
Neck stiffness 
Photophobia  
Reduced level of consciousness

Question 7

List signs of subarachnoid haemorrhage on physical examination

Answer 7

Meningism: Neck stiffness, Kernig’s sign, Pyrexia
GCS deterioration
Signs of raised ICP: papilloedema, III/VI CN palsies, HTN, bradycardia
Focal neurological signs (e.g. CN palsies)
Fundoscopy: Subhyaloid haemorrhage

Question 8

What bloods should be taken in SAH?

Answer 8

FBC
U+Es
ESR/CRP
Clotting

Question 9

What other investigations should be carried out for subarachnoid haemorrhage?

Answer 9

CT: Hyperdense areas in basal regions of the skull (due to blood)
Angiography (CT/ intra-arterial): detect source of bleeding
LP: Increased opening pressure, Increased red cells, Xanthochromia

Question 10

What is xanthochromia?

Answer 10

Straw-coloured CSF due to breakdown of RBCs