Subarachnoid Haemorrhage

Question 1

What is a subarachnoid haemorrhage?

Answer 1

Bleeding into the subarachnoid space (between arachnoid and pia) and is an emergency.

Question 2

What are the 2 types of subarachnoid haemorrhages?

Answer 2

1. Traumatic → Head Trauma
2. Nontraumatic → Ruptured Intracranial Aneurysm (most commonly occurs in the circle of willis, ‘berry’ aneurysms), Arteriovenous Malformations, Anticoagulant Use

Question 3

What are the risk factors of subarachnoid haemorrhages?

Answer 3

• hypertension
• smoking
• FH
• alcohol use
• age >50 yrs old
• Bleeding disorders
• Saccular aneurysms are associated with:
  *Polycystic kidney disease
  *Coarctation of the aorta
  *Marfan’s syndrome
  *Ehlers-Danlos syndrome
  *SLE

Question 4

What are the different causes of a subarachnoid haemorrhage?

Answer 4

• 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
• No cause found in <15%

Question 5

Summarise the epidemiology of subarachnoid haemorrhage

Answer 5

Incidence: 10/100,000
Peak incidence: 40s

Question 6

What are the presenting symptoms of a subarachnoid haemorrhage?

Answer 6

Sudden-onset worst headache ever – typically occipital (thunder-clap headache)
Nausea/vomiting
Collapse
Seizures
Neck stiffness
Photophobia
Reduced level of consciousness

Question 7

What signs of a subarachnoid haemorrhage can be found on physical examination?

Answer 7

1. Meningism
   - Neck stiffness
   - Kernig’s sign
   - Pyrexia
2. GCS - check for deterioration
3. Signs of raised ICP - papilloedema, IV or III nerve palsies, hypertension, bradycardia
4. Focal neurological signs (e.g. cranial nerve palsies) – suggests site of aneurysm

Question 8

What investigations are used to diagnose/ monitor subarachnoid haemorrhage?

Answer 8

1. Bloods
   - FBC
   - U&Es
   - ESR/CRP
   - Clotting
2. Non- contrast CT Scan (best initial diagostic test) – detects >90% of SAH in first 48 hours
   - Hyperdense areas in the basal regions of the skull (due to blood)
3. CT Angiography - detect source of bleeding
4. Lumbar Puncture – if CT –ve but high clinical sus of SAH and no contraindication 12h after headache onset ( this can only be performed 12 hours after symptom onset, due to the need for sufficient red blood cell breakdown to form xanthochromia.)
   - Increased opening pressure
   - Increased red cells
   - CSF is uniformly bloody early on then becomes xanthochromic - straw-coloured/ pink CSF due to breakdown of red blood cells
5. ECG → arrhythmias, prolonged QT, ST segment or T-wave abnormalities
6. Electrolytes → hyponatraemia most common due to SIADH

Question 9

What grading systems are used for subarachnoid haemorrhage?

Answer 9

FISHER- predictor of vasospasm (blood load related) 

WFNS- predictor of long term outcome (deficit related) 

Question 10

How is a subarachnoid haemorrhage managed?

Answer 10

1. Prevention of vasospasm-induced cerebral ischaemia → nimodipine (CCB)
2. Intracranial Aneurysms → endovascular coiling
3. Stop & reverse anticoagulation

Question 11

What complications may arise from a subarachnoid haemorrhage?

Answer 11

Re-bleeding, vasospasm (delayed cerebral ischaemia), hyponatraemia (SIADH), seizures, hydrocephalus