What is Aneurysmal Subarachnoid Hemorrhage?

Subarachnoid Hemorrhage, or SAH, is a medical condition where there is bleeding into the subarachnoid space.  This space is just outside of the brain and spinal cord, but inside the dura, or the tough covering over the brain and spinal cord.  The subarachnoid space contains cerebrospinal fluid, or CSF, which protects the brain, as well as major blood vessels that supply the brain with oxygen and nutrients.

The most common cause of subarachnoid hemorrhage is trauma.  When a patient strikes their head, such as in an automobile accident or fall, blood vessels in the subarachnoid space may tear and bleed, causing traumatic subarachnoid hemorrhage.  This is usually treated with observation and placement of an intracranial pressure monitor, using the Guidelines for the Management of Severe Traumatic Brain Injury.

Patients who present with subarachnoid hemorrhage who have not had a traumatic injury have spontaneous subarachnoid hemorrhage.  This is commonly due to an abnormality of the blood vessels within the subarachnoid space that has caused them to rupture and bleed on their own.  The most common vascular abnormality leading to subarachnoid hemorrhage is a cerebral aneurysm, or brain aneurysm, but other vascular conditions can also cause subarachnoid hemorrhage.  When a patient comes to the hospital with subarachnoid hemorrhage, studies such as CT Angiography or Cerebral Angiography are performed to look for a brain aneurysm or malformation that may have caused the bleeding.

Aneurysmal Subarachnoid Hemorrhage is a medical emergency.  It strikes roughly roughly 30,000 people annually in the United States.  Many of these people are critically ill.  Up to 40% of patients with subarachnoid hemorrhage from a ruptured aneurysm die, and many pass away quickly. Symptoms of SAH include sudden onset severe headache (the worst headache of my life, or thunderclap headache), nausea, vomiting, lethargy, coma, and sometimes focal neurological impairment.  They may also develop seizures, elevated pressure in the brain or hydrocephalus, and aneurysm re-rupture. When patients arrive in the Emergency Department with SAH, they will often require intubation (placement of a breathing tube) and transfer to a specialized hospital, such as a Comprehensive Stroke Center (CSC).

SAH patients are then cared for in neurological intensive care units, usually at Comprehensive Stroke Centers.  The goal of treatment is to support the patient, control blood pressure, and give medications to prevent a complication called vasospasm.  About half of all SAH patients will need a ventricular drain to relieve hydrocephalus, a common complication of subarachnoid hemorrhage.  The ventricular drain is a small catheter or tube that is placed into the fluid-filled spaces in the brain, the ventricles, which drains fluid to a collection system outside of the patient.  This ventricular drain helps reduce the buildup of cerebrospinal fluid and helps relieve elevate intracranial pressure.

Once the patient with SAH is stabilized, the goal is to repair the aneurysm so that it cannot bleed again.  Usually, this is done within the first 24 hours after admission to the hospital. Aneurysm repair does not generally change the condition of the patient, but it does prevent further bleeding from occurring.  A brain aneurysm can be repaired in one of two ways, microsurgical clipping (open surgery) or endovascular embolization (often called coiling).  Microsurgical clipping is done in the operating room, and a craniotomy is performed.  The aneurysm is then “fixed” when a small titanium clip is placed across the bottom of the aneurysm (or neck), which prevents future bleeding. There are risks and benefits to each of these treatments, but most ruptured aneurysms at TMH are treated with endovascular embolization (coiling).

Aneurysm embolization (coiling) is performed in a specialized cath lab, similar to a cardiac cath lab or interventional radiology suite, and is usually performed by an Endovascular Neurosurgeon. Small catheters are placed into the femoral artery in the groin and navigated up into the head, where aneurysms are treated from inside the blood vessels. Click here to learn more about Endovascular Neurosurgery.

The first 10-12 days after aneurysm rupture are usually spent in the ICU, and then the focus of care shifts towards rehabilitation.  The average stay in the hospital is about 3 weeks.  Many patients will require inpatient rehabilitation after aneurysmal subarachnoid hemorrhage.  After a patient leaves the hospital, continued follow up with the neurosurgeon is critical.

Want to learn more?  Check out the Brain Aneurysm Foundation.