Hemorrhage, subarachnoid: Bleeding within the head into the space between two membranes that surround the brain. The bleeding is beneath the arachnoid membrane and just above the pia mater. (The arachnoid is the middle of three membranes around the brain while the pia mater is the innermost one.)
The subarachnoid space is a potential space. It is normally filled with cerebrospinal fluid. With a subarachnoid bleed, the cerebrospinal fluid in the subarachnoid space is bloody.
Subarachnoid hemorrhages are typically acute (sudden). They may follow a head injury or rupture of a blood vessel in the central nervous system (brain and spinal cord) as, for example, because of an aneurysm in the vessel.
Nearly half of people admitted to a hospital with a subarachnoid hemorrhage die within a month. Many of the survivors are left with severe disabilities.
The first-degree relatives of patients with subarachnoid hemorrhage are more likely to develop the condition than those who do not have a family history of it. Smoking, alcohol abuse, and high blood pressure are risk factors for subarachnoid hemorrhage.
Picture of the brain and potentially brain injury areas
Subarachnoid hemorrhage is bleeding in the area between the brain and the thin tissues that cover the brain. This area is called the subarachnoid space.
Emergent management of subarachnoid hemorrhage (SAH), including prehospital care, is critical: An estimated 10-15% of patients die before reaching the hospital.
Signs and symptoms. The classic symptom of subarachnoid hemorrhage is thunderclap headache (a headache described as "like being kicked in the head", or the "worst ...
Subarachnoid hemorrhage is bleeding in the area between the brain and the thin tissues that cover the brain. This area is called the subarachnoid space ...
Subarachnoid hemorrhage can be caused by: Bleeding from an arteriovenous malformation (AVM) Bleeding disorder; Cerebral aneurysm rupture; Head injury