Sub-Arachnoid Haemorrhage

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

Presentation

  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.

45q-77

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.

JClinImagingSci_2012_2_1_75_104308_u1

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.

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Causes

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

Investigations

  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)

Management

  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 prevention of vasospasm
  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.

Complications

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

Grading System

Three common grading scores used in SAH are:

  • WFNS (World Federation Neurosurgical Society)
  • Hunt and Hess Score
  • Fisher score

For Medical School/Early Post-graduate level detailed knowledge of these are not required.