What describes a subarachnoid hemorrhage (SAH)?

A subarachnoid hemorrhage (SAH) is characterized by bleeding that occurs specifically in the subarachnoid space, which is the area between the brain and the tissues covering it (the arachnoid mater and pia mater). This type of hemorrhage is often caused by the rupture of an aneurysm or a vascular malformation, leading to the accumulation of blood in this space. Understanding that SAH involves bleeding helps delineate it from other conditions, such as infections, blockages, or temporary strokes, as those conditions have different mechanisms and consequences. Recognizing the unique nature of SAH is critical because it can lead to significant complications, including increased intracranial pressure and brain damage, which require immediate medical intervention.