Subarachnoid Haemorrhage

Question 1

What is the pathophysiology of SAH?

Answer 1

• Acute cerebrovascular event
• Aneurysm formation is due to haemodynamic stress and extensive inflammatory and immunological reactions are common in unruptured intracranial aneurysms and may be related to aneurysm formation and rupture
• Can be caused by trauma

Question 2

What are the symptoms of SAH?

Answer 2

• Sudden onset headache (<5 minutes)
• Loss of consciousness
• Seizures
• Visual disturbance
• Photophobia
• Limb disturbance (weakness)
• Speech disturbance
• Sentinel headaches

Question 3

What are the predisposing factors for SAH?

Answer 3

• Risk factors:
  
  • Smoking
  • HTN
  • Excessive alcohol consumption
  • FHx
  • Cocaine use
• More common in:
  
  • Females
  • Black patients
  • Age 45-70
• Associated with:
  
  • Sickle cell anaemia
  • ADPKD
  • Connective tissue disease (i.e. Ehlers Danlos, Marfan’s)
  • Coarctation of the aorta
  • Neurofibromatosis

Question 4

How is SAH diagnosed and investigated?

Answer 4

• Clincal examination shows photpphobia, meningism, subhyloid haemorrhages, speech/limb disturbance and pulmonary oedema
• CT head - hyperattenuation in the subarachnoid space (confirms diagnosis but probability of detection decreases with time)
• LP (red cell count will be raised, xanthochromia is yellowing of CSF by bilirubin from breakdown of oxy Hb present in CSF due to epidural bleeding)
• Angiography (CT, MRI)

Question 5

How is SAH managed?

Answer 5

• Managed in specialist neurosurgical unit
• May require intubation and ventilation
• Surgical intervention
  
  • Surgical clipping
  • Endovascular (coils, stents and glue)
• Nimodipine (prevent vasospasm)
• Anti-embolic stockings
• LP or insertion of a shunt
• Antiepileptic medications can be used to treat seizures
• Analgesia

Question 6

What are the complications of SAH?

Answer 6

• Re-haemorrhage
• Delayed ischaemia
• Hydrocephalus
• Hyponatraemia
• Cardiopulmonary complications (e.g. arrhythmias)
• Seizures
• DVT