Subarachnoid Haemorrhage (SAH) & OTHERS

Question 1

Define subarachnoic haemorrhage (SAH)

Answer 1

Spontaneous arterial leeding into the subarachnoid space

Not neccesarily ‘traumatic’

Question 2

What is the aetiology of a SAH?

Answer 2

• Saccular (‘berry’) aneurysm - 70%
  
  • Aquired lesions most commonly located at branching points of major arteries in subarachnoid space (circle of Willis)
• Congenital arteriovenous malformations - 10%
• No lesion found - 20%

Question 3

Draw the Circle of Willis

Answer 3

Question 4

Outline the common areas of intracranial aneurysms (diagram)

Answer 4

Question 5

Draw the vertebral-basilar/ posterior system

Answer 5

Question 6

Draw the carotid/ anterior system

Answer 6

Question 7

Outline the vessel present

• Scalp
• Skull
• Epidural
• Subdural
• Subarachnoid
• Grey mater

Answer 7

• Scalp - Superficial veins
• Skull - Diploic veins
• Epidural - Mid. meningeal artery
• Subdural - Bridgeing veins & sinuses
• Subarachnoid - Circle of Willis
• Grey mater - Cortical vessels

Question 8

Draw the areas of supply in the brain

Answer 8

Question 9

Outline the clinical features of a SAH & intracranial aneurysms

Answer 9

• Aneurysms
  
  • Usually asymptomatic until rupture & SAH
  • Occasionally mass effect causes symptoms - 3rd nerve palsy common (post. communicating artery)
• SAH Symptoms
  
  • Thunderclap, occipital, worst-ever headache reaching maximum intensity within minutes
  • Nausea & vomiting
  • **LOC **& seizures
• SAH Signs
  
  • Meningeal irritation - neck stiffness & +ve Kernig’s sign (>6hr)
  • Focal neurological signs
  • Retinal, Sybhyaloid (between retina & vitreous membrane) or Vitreous bleeds (Terson’s syndrome) +/- papilloedema
  • 3rd nerve palsy (post. communicating artery)
  • Sentinal headache - herald bleed

Question 10

Outline the types of intracranial haemorrhages and their common presentations

(other than SAH)

Answer 10

• Epi/extradural - between dura & skull
  
  • Middle meningeal artery
  • Rapid LOC, lucid interval, then sudden deterioration
• Subdural - between arachnoid & under dura
  
  • Tearing of bridgeing veins in subdural space
  • Slower
  • CT - crescent shape deformity
• Intracerebral
  
  • Spontaneously (stroke) or trauma
  • Location determine symptoms
  • Headache & vomitting common
• Cerebellar
  
  • Headache, stupor/ coma
  • Cerebellar signs
  • Gaze deviates towards haemorrhage

Question 11

Outline the investigations for a suspected SAH

Answer 11

• CT Head
  
  • SAH/ intraventricular blood in 95% within 24hrs (sensitivity dec. with time)
• ⇒ Lumbar puncture (if CT normal)
  
  • RBC phagocytosis → ↑bilirubin &** ​↑oxyhaemoglobin (both)**
  • Present >12hrs after symptom onset
  • Spectrophotometry of supanatant after centrifugation of last fraction of CSF taken from LP
  • Protect specimen from light
  • Detectable <2weeks
• MR Angiography
  
  • Establish source of bleeding in all patients potentially fit for surgery

Question 12

Outline the management of SAH

Answer 12

• ABC
• Cerebral perfusion
  
  • ↑SBP >160 to ↑perfusion (careful of ↑haemorrhage)
  • Hydration
  • **Treat hyponatraemia **(as causes ↓​perfusion)
    
    • How? DO NOT fluid restrict.
• Nimodipine (60mg/4hr PO for 3wks) - Ca²⁺ antagonist
  
  • ↓vasospasm & consequent ischaemia
• Surgery
  
  • Endovascular coiling
  • Surgical clipping

Question 13

Outline SAH’s potential complications

Answer 13

• Rebleeding
  
  • Commonest
  • Caution with BP
• Cerebral ischaemia & infarction
  
  • Due to vasospasm
  • May cause permanent neurological deficit
  • Prevention: Nimodipine for 3wks
• Hydrocephalus
  
  • Arachnoid granulations blocked
  • Ventricular/ lumbar drain
• Hyponataemia
  
  • Common
  • Do not manage by fluid restricting