Subarachnoid haemorrhage Flashcards
What is it
Spontaneous bleeding into the subarachnoid space
often catastrophic
Incidence
9/100000/yr
Typical age affected
35-65
Management
Any known SAH immediately refer to neurosurgery
Re-examine CNS often - chart BP, pupils and GCS (repeat CT if deteriorating)
Maintain cerebral perfusion by keeping well hydrated
Reduce vasospasm by NIMODIPINE (Ca2+ antagonist)
Surgery
Where is the subarachnoid space
Between arachnoid layer of meninges and pia mater
What is the most common cause of rupture
Berry aneurysm
Aetiology
Rupture of saccular aneurysms (80%) e.g. berry aneurysm
Atriovenous malformation (10%)
No cause found (5%)
Others e.g. bleeding disorder, acute bacterial meningitis, mycotic aneurysms (endocarditis) etc
What is berry aneurysm rupture
Rupture of the junction of the posterior communicating artery with the internal carotid or of the anterior communicating artery with the anterior cerebral artery - in the circle of Willis
What % of rupture of saccular aneurysms are multiple
15%
Describe what is meant by atriovenous malformation
Vascular developmental malformation often with a fistula between arterial and venous systems causing high flow through the AVM and high-pressure arterialisation of draining veins
Risk factors
Hypertension
Known aneurysm
Family history
Smoking, bleeding disorders, post-menopausal decreased oestrogen
Disease that predispose to aneurysm:
Polycystic kidney disease, Coarctation of aorta, Ehlers Danlos syndrome
Pathophysiology
Most common cause is ruptured aneurysm which leads to tissue ischaemia (since less blood can reach tissue) as well as rapid raised ICP as the blood (fast flowing since arterial), acts like a space-occupying lesion, puts pressure on the brain, resulting in deficits if not resolved quickly
Clinical presentation
SUDDEN onset - severe occipital headache - thunderclap (like being kicked in the head)
Followed by vomiting, collapse, seizures and coma
Other features of clinical presentation
Dpressed level of consciousness Coma/drowsiness may last for days Neck stiffness Kernig's sign and Brudzinski's sign Retinal and vitreous bleeds Papilloedema (dilated optic disc) Vision loss or diplopia (double vision) (High BP as a reflex to following haemorrhage)
What is Kernig’s sign and Brudzinski’s sign
Kernig’s sign = unable to extend patients leg at the knee when the thigh is flexed
Brudzinski’s sign = when patients neck is flexed by doctor, patient will flex their hips & knees
