Subarachnoid Haemorrhage

Question 1

Definition

Answer 1

Arterial haemorrhage into the subarachnoid space

Question 2

Aetiology

Answer 2

· 85% - rupture of a saccular aneurysm at the base of the brain (Berry aneurysms)

· 10% - perimesencephalic haemorrhage

· 5% - arteriovenous malformations, bleeding diathesis, vertebral artery dissection

Question 3

Risk factors

Answer 3

o Hypertension

o Smoking

o Excess alcohol intake

o Saccular aneurysms are associated with:
· Polycystic kidney disease
· Marfan’s syndrome
· Ehlers-Danlos syndrome

Question 4

Epidemiology

Answer 4

· Incidence: 10/100,000

· Peak incidence: 40s

Question 5

Presenting symptoms

Answer 5

· Sudden-onset worst headache ever
· Nausea/vomiting
· Neck stiffness
· Photophobia
· Reduced level of consciousness

Question 6

Signs on physical examination

Answer 6

· Meningism
o Neck stiffness
o Kernig’s sign
o Pyrexia

· GCS - check for deterioration

· Signs of raised ICP - papilloedema, IV or III nerve palsies, hypertension, bradycardia

· Focal neurological signs (e.g. cranial nerve palsies)

Question 7

Investigations

Answer 7

· Bloods
o FBC
o U&Es
o ESR/CRP
o Clotting

· CT Scan
o Hyperdense areas in the basal regions of the skull (due to blood)

· Angiography - detect source of bleeding

· Lumbar Puncture
o Increased opening pressure
o Increased red cells
o Xanthochromia - straw-coloured CSF due to breakdown of red blood cells