Subarachnoid Haemorrhage Flashcards
What is subarachnoid haemorrhage?
Refers to extravasation of blood in the SA space between the pia and arachnoid membrane
What can cause subarachnoid haemorrhage?
Head trauma or can be non-traumatic
Main cause of non-traumatic SAH?
Rupture of intracranial (berry) aneurysm
Why do berry aneurysms form?
Due to congenital weakness of elastic tissues in the arterial wall
What increases risk of berry aneurysms?
Increases with age
HT
Where do aneurysms often develop?
Near arterial junctions in circle of Willis
Factors which make intracranial haemorrhages more likely to rupture?
- Smoking
- HT
- Location of anuerysm
- Size of aneurysm
- Conditions such as polycystic kidney disease
Other causes of non-traumatic subarachnoid haemorrhage?
Arteriovenous malformations
Bleeding disorders
Clinical features of subarachnoid haemorrhages?
- Sudden onset of ‘thunderclap headache’ patients claim its the worst headache ever
- Neck stiffness and photophobia
- Often accompanied by vomiting/nausea
- Third nerve palsy may occur (if posterior communicating artery)
- Confusion, seizures and loss of consciousness can occur
- Can get vitreous haemorrhage assoc with SAH
Diagnosis of SAH?
Usually confirmed with unenhanced CT scan where large volume of blood which appears to white is seen in suprasellar cistern, sylvian fissures and sulci
What to do if in doubt about SAH diagnosis?
Lumbar puncture
-Checking CSF for signs of blood
What happens when there is SA blood found in absence of history of trauma?
CT cerebral angiography is performed to look for berry aneurysm
Immediate treatment of SAH?
Bed rest and supportive measures
- Control HT
- Nimodipine (CCB for 3 weeks, reduces mortality)
First line treatment when angiography demonstrates aneurysm?
Endovascular treatment by placing platinum coils via a catheter in the aneurysm sac (To promote thrombosis)
AND
Ablation of aneurysm
Complications of SAH?
- Vasospasm
- Re-bleed
- Seizures
- Hyponatraemia
Why does vasospasm occur?
Because blood in the SA space is very irritating to vessels
-Can be prolonged arterial contraction leafing to delayed ischaemic neurological deficits
When does vasospasm usually peak?
3-14 days following haemorrhage
Presnetation of vasospasm?
Development of new focal neurological deficit
Present with altered state of consciousness
Diagnosis of vasospasm?
Clinical diagosis and confirmed with angiogram
OR less invasively with transcranial doppler
Treatment for vasospasm?
Use of nimodipine and BP control
Management of rebleedinga dn when it is most common?
- First 2 weeks + in elderly/HT patients
- Managed with surgical clipping or coiling
