What is the most common cause of subarachnoid hemorrhage?

What is the most common cause of subarachnoid hemorrhage?

• A. Hypertensive hemorrhage
• B. Trauma
• C. Aneurysm leak
• D. Arteriovenous malformation rupture

Answer: (D)

Subarachnoid hemorrhage is most commonly caused by rupture of a saccular (berry) aneurysm in the circle of Willis. These aneurysms are weakened arterial walls that can burst suddenly under hemodynamic stress, spilling blood into the subarachnoid space and producing the classic sudden, severe “thunderclap” headache. Arteriovenous malformations can also rupture and cause SAH, but they account for a much smaller share of cases. Hypertensive hemorrhage typically produces bleeding within the brain tissue (intraparenchymal) rather than primarily in the subarachnoid space, and trauma can cause SAH as well, but it is not the most common cause of spontaneous SAH.

Subarachnoid hemorrhage is most commonly caused by rupture of a saccular (berry) aneurysm in the circle of Willis. These aneurysms are weakened arterial walls that can burst suddenly under hemodynamic stress, spilling blood into the subarachnoid space and producing the classic sudden, severe “thunderclap” headache. Arteriovenous malformations can also rupture and cause SAH, but they account for a much smaller share of cases. Hypertensive hemorrhage typically produces bleeding within the brain tissue (intraparenchymal) rather than primarily in the subarachnoid space, and trauma can cause SAH as well, but it is not the most common cause of spontaneous SAH.