Subarachnoid haemorrhage

Question 1

Define

Answer 1

• Arterial haemorrhage into the subarachnoid space

* EMERGENCY

Question 2

What are the causes?

Answer 2

• 85% - rupture of a saccular aneurysm at the base of the brain (Berry aneurysms shown in picture)
o Cerebral aneurysms arise at the bifurcation of major arteries that form the circle of Willis.
• 10% - perimesencephalic haemorrhage
• 5% - arteriovenous malformations, bleeding diathesis, vertebral artery dissection

Question 3

What are the risk factors?

Answer 3

o	Hypertension
o	Smoking 
o	Excess alcohol intake 
o	Positive family history
o	Saccular aneurysms are associated with:
•	Polycystic kidney disease 
•	Marfan's syndrome
•	Ehlers-Danlos syndrome

Question 4

What’s the epidemiology?

Answer 4

• Incidence: 10/100,000

* Average age: 50-55

Question 5

What are the presenting symptoms?

Answer 5

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

Question 6

What are the signs?

Answer 6

• Meningismus
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

What are the appropriate investigations?

Answer 7

• Bloods
o FBC – high WCC
o U&Es
o ESR/CRP
o Clotting – high INR, prolonged PTT
• CT Scan
o Hyperdense areas in the basal regions of the skull (due to blood)
• Angiography - detect source of bleeding
• ECG – 50% of patients with SAH have abnormal ECG on admission
• Lumbar Puncture
o Increased opening pressure
o Increased red cells
o Xanthochromia - straw-coloured CSF due to breakdown of red blood cells