10- Subarachnoid Haemorrhage

Question 1

What are risk factors for subarachnoid haemorrhage?

Answer 1

Hypertension, smoking, excessive alcohol, family history, other conditions (CKD, Marfan’s, neurofibromatosis), trauma and cocaine use

Question 2

What is the usual pathophysiology of a SAH?

Answer 2

Rupture of an aneurysm in the circle of Willis

Question 3

Which vessels are most prone to berry aneurysms who’s rupture can cause subarachnoid haemorrhage?

Answer 3

Anterior communicating artery (30%), posterior communicating artery (25%), bifurcation of middle cerebral artery into superior and inferior division (20%)

Question 4

What other structures can be affected by a berry aneurysm of the anterior communicating artery?

Answer 4

Can compress the optic chasm and may affect frontal lobe or pituitary

Question 5

What other structures can be affected by a berry aneurysm of the posterior communicating artery?

Answer 5

Oculomotor nerve giving rise to a ipsilateral third nerve palsy

Question 6

Why do you get vasoconstriction with SAH leading to early brain injury?

Answer 6

A result of blood in the CSF irritating cerebral arteries

Question 7

What are the clinical features of a SAH?

Answer 7

Thunderclap headache, LOC, confusion meningism. May be focal neurology, previous headache or cardiac arrest

Question 8

Why can SAH cause cardiac arrest?

Answer 8

Myocardial necrosis following sympathetic activation

Question 9

What is likely to be seen on head CT if there is a subarachnoid haemorrhage?

Answer 9

Prominent filling of the basal cisterns in a star pattern and blood may be present in ventricles

Question 10

What investigations can be carried out if a SAH is suspected?

Answer 10

Head CT, CT angiogram, lumbar puncture

Question 11

What lumbar puncture finings can be seen in subarachnoid haemorrhage?

Answer 11

Increased opening pressure, frank blood or xanthochromia, high protein, high red cell count, normal white cell and glucose

Question 12

What neurosurgery can be used to treat subarachnoid haemorrhage?

Answer 12

Craniectomy (decompressive surgery) and coiling or clipping of the aneurysm

Question 13

What is xanthochromia seen in a lumbar puncture?

Answer 13

Yellow colouring of CSF due to haemoglobin breakdown to bilirubin in subarachnoid space- seen 12+ hours post bleed

Question 14

What is coiling as a treatment for a berry aneurysm/rupture?

Answer 14

Insertion of platinum wire into aneurysm to promote thrombosis of blood in the aneurysm