Subarachnoid Haemorrhage

Posted by

Learning Objectives

  1. Recognise the presentation of a Sub-Arachnoid Haemorrhage (SAH)
  2. List the causes of a SAH
  3. Recognise the key features on a CT Scan
  4. Outline radiological features on CT scan to Cerebral Vascular Anatomy
  5. Describe the Management of a SAH
  6. Describe the Complications of a SAH

Risk Factors

  1. Hypertension
  2. Family history of aneurysm
  3. Smoking
  4. Pregnancy
  5. COCP
  6. Illicit Drug Substances

Associated Conditions

  1. Polycystic Kidney Disease
  2. Co-Arctation of Aorta
  3. Ehrlos-Danlos Syndrome
  4. Marfan’s Syndrome


  1. Sudden onset headache (thunderclap)
  2. Photophobia
  3. Nausea and Vomiting
  4. Collapse
  5. Weakness
  6. Blurred Vision- (sub-hyaloid, sub-retinal, intra-retinal haemorrhage)
  7. New onset Neck Pain

Examination Findings

  1. Meningitis symptoms- Positive Kernigs and Brudzinskis sign
  2. Weakness
  3. Third Nerve Palsy (associated classically with PCOM aneurysms)
  4. Reduced GCS
  5. Blurred vision

Radiology Findings

CT Scan- shows the presence of blood within the basal cistern (5 point star) with an associated right temporal haematoma associated with a ruptured middle cerebral artery aneurysm. The CTA is shown below pointing to the associated aneurysm.


CT scan presence of blood within the cisterns, with associated hydrocephalus. Note the presence of blood within the sylvian fissure. The presence of blood within the sylvian fissure should indicate a ruptured middle cerebral artery aneurysm or posterior communicating artery aneurysm.


CT Scan below reflects the presence of blood within the anterior inter-hemispheric fissure characteristic of a ruptured anterior cerebral artery aneurysm or anterior communicating artery aneurysm.



  1. Traumatic- the most common cause of a SAH
  2. Aneurysmal
  3. Arterio-Venous Malformation
  4. Cavernoma
  5. Mycotic Aneurysm (associated with infective endocarditis)


  1. Blood tests (inc G+S)
  2. ECG- exclude sub-endocardial ischaemia, stunned myocardium and life-threatening ventricular arrythmia’s)
  3. CXR- to exclude neurogenic pulmonary oedema if indicated
  4. CT scan- note sensitivity of CT scan decreases after 72 hours of initial presentation. It is 98% sensitive for the detection of a SAH within 12 hours of presentation. The CT scan is a high resolution NON-CONTRAST CT.
  5. If CT scan is negative a Lumbar Puncture should be performed only 12 after initial onset of symptoms. The detection of transient xanthocromia (bilirubin) takes at least 12 hours to become detectable, hence performing a Lumbar Puncture is futile prior to this.
  6. Once LP or SAH positive than perform a CTA. If CTA negative than perform Digitial Subtraction Angiography (DSA)


  1. NBM
  2. IV Fluids- 3 litres of fluid over 24 hours
  3. Maintain Mean Arterial Pressure between 120-150mmHg
  4. Flat bed rest- improve Cerebral Perfusion
  5. Laxatives- to prevent straining hence reducing ICP
  6. Nimodipine 60mg every 4hrly for 21 days
  7. Analgesia- Morphine/ IV Paracetamol

Surgical Management

  1. Endovascular Coiling- method of choice
  2. Surgical Aneurysmal Clipping (less commonly favoured in the UK

The ISAT 2002 (International Sub-Arachnoid Aneurysmal Trial) non-blinded, randomised control trial comparing 2143 patients whose aneurysm were either coiled or clipped.

There was a significant improvement in 1 year survival free disability with endovascular coiling vs aneurysmal clipping, however the long term risk of re-bleeding whilst low with both interventions is increased with aneurysmal clipping.


Cranial Complications

  1. Re-bleed
  2. Cerebral Vasospasm
  3. Hydrocephalus (communicating vs non-communicating)
  4. Seizures
  5. Cerebral Salt Wasting Syndrome vs SIADH (Hyponatraemia)

Extra-Cranial Complications

  1. Cardiac- Stunned Myocardium, Sub-Endocardial Ischaemia, Life threatening arrythmia’s, SVT
  2. Respiratory- Neurogenic Pulmonary Oedema
  3. Visual- Vitreous Haemorrhage- Terson’s Syndrome


Leave a Reply