Subarachnoid Haemorrhage

Question 1

What is subarachnoid haemorrhage?

Answer 1

Spontaneous arterial bleeding into the subarachnoid space ; often catastrophic

Commonly occurs between 35-65yrs

Accounts for 5% of strokes

Question 2

What are the causes of subarachnoid haemorrhage?

Answer 2

Saccular berry aneurysm rupture (80%)

Arteriovenous malformations (15%)

Other causes: 
=> Bleeding disorders  
=> Encephalitis  
=> Acute bacterial meningitis 
=> Vasculitis 
=> Coarctation of aorta 
=> Marfans / Ehlers-Danlos syndromes
=> Arteritis e.g. SLE 
=> Mycotic aneurysm - endocarditis 
=> Acute polycystic kidney disease
=> Tumour (invading blood vessels)

Question 3

Saccular berry aneurysms develop within the circle of willis and adjacent arteries.

What are the most common sites for berry aneurysms to occur?

Answer 3

Common sites are at arterial junctions:

1. Between posterior communicating and internal carotid artery => posterior communicating artery aneurysm
2. Between anterior communicating and anterior cerebral artery => anterior communicating artery aneurysm
3. At the bifurcation of the middle cerebral artery => middle cerebral artery aneurysm

Question 4

What are the symptoms of subarachnoid haemorrhage?

Answer 4

Sudden onset excruciating headache ; occipital ; “thunderclap headache”

Followed by vomiting

Collapse ; seizures ; coma

*Coma/drowsiness may last for days

Question 5

What are the signs of subarachnoid haemorrhage?

Answer 5

Neck stiffness

Kernig’s sign positive - takes 6h to develop
=> thigh flexed at the hip + knee at 90 degree angles, and subsequent extension in the knee is painful

Retinal / subhyaloid / vitreous haemorrhage ± papilloedema

Focal neurology at presentation may suggest site of aneurysm i.e. pupil changes indicating 3rd nerve palsy => posterior communicating artery aneurysm

Question 6

What are the risk factors of subarachnoid haemorrhage?

Answer 6

Previous subarachnoid aneurysm

Smoking

Alcohol misuse

High BP

Bleeding disorders

Subacute bacterial endocarditis (mycotic aneurysm)

Family Hx => 3-5x increased risk

Polycystic kidneys

Aortic coarctation

Ehlers-Danlos syndrome

Question 7

How do you investigate subarachnoid haemorrhage?

Answer 7

1. Urgent CT

=> detects >95% of subarachnoid haemorrhage within first 24h

2. Lumbar puncture only if in doubt i.e. CT negative but Hx very suggestive of subarachnoid haemorrhage

=> CSF becomes yellow (xanthochromic) within 12h of subarachnoid haemorrhage

=> Yellow due to bilirubin accumulation from breakdown of RBC

3. CT angiography or catheter angiography to identify single/multiple aneurysm in patients fit for surgery

Question 8

What are the differential diagnosis for subarachnoid haemorrhage?

Answer 8

Meningitis

Migraines

Intracerebral bleed

Cortical vein thrombosis

Carotid or vertebral artery dissection

Benign thunderclap headache (usually idiopathic)
=> triggered by valsalva manoeuvre e.g. cough, coitus

=> reversible cerebral vasoconstriction – Call-Fleming’s syndrome

Question 9

How do you manage subarachnoid haemorrhage?

Answer 9

Refer all proven subarachnoid haemorrhage to neurosurgery immediately

Re-examine CNS often ; chart BP ; pupils and GCS

Repeat CT if deteriorating

Cerebral perfusion by keeping well hydrated
=> aim for SBP <160mmHg

Nimodipine (calcium channel blocker)
=> reduces vasospasm thus reduces morbidity from cerebral ischaemia

Surgical options:
=> Endovascular coiling

=> Surgical clipping (requires craniotomy)

Question 10

What is the first line treatment for subarachnoid haemorrhage?

Answer 10

Platinum coils via a catheter in the aneurysm sac to promote thrombosis and ablation of the aneurysm

=> Endovascular coiling has a lower complication rate than surgery

=> But direct surgical clipping still effective in selective patients

Question 11

What are the complications of subarachnoid haemorrhage?

Answer 11

1. Rebleeding => commonest cause of death ; occurs in 20%
2. Cerebral ischaemia => commonest cause of morbidity
   => due to vasospasm - may cause a permanent CNS deficit
3. Hydrocephalus => requires ventricular or lumbar drain
   => due to blockage of arachnid granulation
4. Arterial spasms => visible on angiography
   => cause of coma or hemiparesis
   => serious complication + poor prognosis
5. Hyponatraemia => common but restrict fluid

Question 12

Mortality in subarachnoid haemorrhage increases with these signs:

Grade 1 : no signs => 0% mortality

Grade 2 : Neck stiffness & cranial nerve palsies => 11%

Grade 3 : Drowsiness => 37%

Grade 4 : Drowsy with hemiplegia => 71%

Grade 5 : Prolonged coma => 100% mortality

Answer 12

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