Subarachnoid haemorrhage Flashcards
What is a subarachnoid haemorrhage
Spontaneous bleeding into the subarachnoid space
Describe the incidence of subarachnoid haemorrhage
9/100000/year
What age does subarachnoid haemorrhage present
35-65
Describe the symptoms of subarachnoid haemorrhage
Sudden onset excruciating headache - typically occipital, thunderclap
Vomiting
Collapse
Seizures
Coma
Preceding sentinel headache - small warning leak from the offending aneurysm
What are some causes of subarachnoid haemorrhage
Berry aneurysm rupture (80%) Arterio-venous malformations (15%) Encephalitis Vasculitis Tumour (invading blood vessels) Idiopathic
List the common sites of subarachnoid haemorrhage
Junctions of posterior communicating with the internal carotid or of the anterior communicating with the anterior cerebral artery or bifurcation of the middle cerebral artery
What are some risk factors for subarachnoid haemorrhages
Previous aneurysmal SAH Smoking Alcohol misuse HTN Bleeding disorders SBE Polycystic kidneys Aortic coarctation Ehlers Danlos syndrome Family history
What are the differentials of subarachnoid haemorrhages
Meningitis Migraine Intracerebral bleed Cortical vein thrombosis Dissection of carotid or vertebral artery Benign thunderclap headache
What triggers benign thunderclap headache
Coitus
Cough
Valsalva manoeuvre
What investigations would you do when suspecting a subarachnoid haemorrhage
Urgent CT (detects >95% in the first 24hrs)
Consider LP if CT normal and no CI >12hrs after headache onset to allow breakdown of RBCs so a positive sample is xanthochromic (yellow due to blood breakdown and bilirubin)
How do you manage a subarachnoid haemorrhage
Refer all to neurosurgery immediately
Re-examine CNS often, chart BP, pupils and GCS
Repeat CT if deteriorating
Maintain cerebral perfusion by keeping well hydrated, aim SBP <160mmHg
Nimodipine 60mg/4h PO for 3 weeks or 1mg/h IVI is a ca2+ antagonist that reduces vasospasm and consequent morbidity from cerebral ischaemia
Surgery - endovascular coiling vs surgical clipping (requiring craniotomy) - the decision depends on the accessibility and size of the aneurysm through coiling is preferred where possible
Catheter or CT angiography to identify single vs multiple aneurysms before intervening
List the complications of subarachnoid haemorrhage
Rebleeding - commonest cause of death and occurs in 20%, often in 1st few days
Cerebral ischaemia - due to vasospasm may cause
permanent CNS deficit
Hydrocephalus - due to blockage of arachnoid granulations, require ventricular or lumbar drain
Hyponatraemia - common and should not be managed with fluid restriction. Seek help. Syndrome of inappropriate ADH
What are the signs and mortality in grade I subarachnoid haemorrhage?
No signs
0% mortality
What are the signs and mortality in grade II subarachnoid haemorrhage?
Neck stiffness and cranial nerve palsies
11%
What are the signs and mortality in grade III subarachnoid haemorrhage?
Drowsiness
37%
