Subarachnoid Hemorrhage - Sentinel Bleed.
Sentinel bleed is a warning bleed due to minor blood leakage, precedes aneurysm rupture by a few hours to a few months, present with sudden focal or generalized headache, should not be overlooked must be screened on time to rule out underlying aneurysm with non invasive MR Angio or DSA.
Subarachnoid Hemorrhage – Massive and diffuse.
Most common causes of spontaneous SAH are rupture of a saccular (berry) aneurysm (80%) and rupture of an arteriovenous malformation (AVM) (10%). Causes of non aneurysmal SAH include amyloid angiopathy, blood dyscrasias, fibromuscular dysplasia, Moyamoya disease, vasculitis (10%)
As per the Law of La Place, the tension on the wall is proportional to the diameter. Thus, the rate of rupture is directly related to the size of the aneurysm.
Aneurysms usually occur at arterial bifurcations and mostly arise from the anterior circulation of the Circle of Willis (85%).
|Left ACA Aneurysm|
|Basilar tip Aneurysm|
|MCA bifurcation Aneurysm|
|ICA Tip Aneurysm|