Subarachnoid haemorrhage Flashcards
define SAH?
arterial haemorrhage into the subarachnoid space
what is the most common cause of SAH?
trauma
what are the causes of spontaneous SAH?
- 85% - Berry aneurysms (rupture of a saccular aneurysm at the base of the brain)
- 10% - perimesencephalic haemorrhage
- 5% - arteriovenous malformations, bleeding diathesis, vertebral artery dissection
what are general risk factors for SAH?
o Hypertension
o Smoking
o Excess alcohol intake
what are risk factors for berry aneurysms?
- Polycystic kidney disease
- Marfan’s syndrome
- Ehlers-Danlos syndrome
epidemiology of SAH?
- Incidence: 10/100,000
* Peak incidence: 40s
what are the presenting symptoms of SAH?
- Sudden-onset worst occipital headache ever (thunderclap)
- Nausea/vomiting
- Meningism (photophobia/neck stiffness)
- Reduced level of consciousness
- Coma
- Seizures
- Sudden death
what are the signs to look for of SAH?
- Meningism
- GCS
- Signs of raised ICP - papilledema, IV or III nerve palsies, hypertension, bradycardia
- Focal neurological signs
- ECG changes like ST elevation
why might bloods be important for SAH?
o U&Es (important for hyponatraemia caused by SIADH
what is the first line investigation?
• CT Scan
o Acute blood is present (bright on CT)
o CT can be present with NO blood in 7% of occasions
what is the confirmatory investigation?
• Lumbar Puncture
o Used to confirm SAH if the CT is negative
o The LP needs to be performed at least 12 hours following symptoms to all the development of RBC breakdown
o Break down products of RBCs like BR
what investigation might be finally undertaken?
• CT intracranial angiogram
o To identify the vascular lesion
o Digital subtraction angiogram optional
where should patient be referred if positive?
Referral to neurosurgery asap once confirmed SAH
