Subarachnoid haemorrhage

Question 1

What is a SAH?

Answer 1

Spontaneous bleeding into the subarachnoid space which is often catastrophic.

Question 2

What are causes of SAH?

Answer 2

• Rupture of a Berry aneurysm (80% of cases). Common sites include junction of posterior communicating with IC, or anterior communicating with anterior cerebral artery.
  
  • AVM (15%)
  • Others (less common) include encephalitis, vasculitis, tumour

Question 3

What are risk factors for SAH?

Answer 3

Smoking, age, cocaine, HTN, anticoagulants, bleeding disorders
Marfan, Ehlers Danlos, APKD, NF 1, coarctation of aorta

Question 4

What is presentation of SAH?

Answer 4

Thunderclap headache - occipital, reaches intensity within 5 minutes
vomiting, collapse, seizures, coma

may be a warning sentinel headache

Question 5

What are signs of SAH?

Answer 5

Neck stiffness and Kernig’s sign (6h)
Retinal, subhyaloid, vitreous bleeds
Focal neurology

Question 6

What are differentials for SAH?

Answer 6

• Meningitis
  
  • Migraine
  • IC bleed
  • Cortical vein thrombosis
  • Dissection of carotid or vertebral artery
  • Benign thunderclap

Question 7

What investigations for SAH?

Answer 7

CT head

LP if CT is -ve and suggestive Hx, 12 hours after onset

Question 8

What is management of SAH?

Answer 8

Neurosurgery.
Endovascular coiling or surgical slipping.

CT angio first to identify aneurysms

Nimodipine Ca2 antagonist IV that reduces vasospasm and consequent morbidity from cerebral ischaemia.

IV fluids

Question 9

What are complications of SAH?

Answer 9

Rebleeding

Cerebral ischaemia due to vasospasm

Hydrocephalus: due to blockage of arachnoid granulations, need ventricular or lumbar drain

Hyponatraemia