An Overview Subarachnoid Hemorrhage

A subarachnoid hemorrhage is a type of bleeding in the brain that can produce stroke-like symptoms. A subarachnoid hemorrhage is a serious medical emergency that is typically very sudden. Find out more about how to recognize a subarachnoid hemorrhage and what to expect if you have been diagnosed with this condition.

What is a subarachnoid hemorrhage? 

The word hemorrhage means bleeding. The word arachnoid describes a specific protective structure around the brain.

The arachnoid is one of the 3 sheets of protective covering that surround and cushion the brain. These layers are called meninges. In between the arachnoid and the layer closest to the brain, called the pia, there is the subarachnoid space. Within this space, there are blood vessels and cerebrospinal fluid. If one of these blood vessels bursts, then bleeding will occur around the brain, underneath the arachnoid layer. This is why it is called a subarachnoid hemorrhage (bleeding underneath the arachnoid.)

What are the symptoms of a subarachnoid hemorrhage?

The most common symptom of a subarachnoid hemorrhage is severe head pain. The blood that leaks underneath the arachnoid and directly above the brain tissue causes severe irritation and pain. Typically, the pain is unrelenting, affecting the whole head and the area behind the eyes. The pain usually worsens with head movement.

There are other neurological symptoms that accompany a subarachnoid hemorrhage, and they differ from one person to another depending on which blood vessel was injured and where the bleeding affected the brain.

Symptoms such as loss of vision, double vision, facial weakness, inability to control tongue movement, numbness and tingling or weakness of the arms or legs may occur with a subarachnoid hemorrhage. The neurological symptoms may come and go, but the severe head pain persists. Dizziness, nausea, and vomiting may develop and these symptoms often worsen quickly.

 In some instances, a subarachnoid hemorrhage can cause a seizure.

What are the effects of a subarachnoid hemorrhage?

A subarachnoid hemorrhage can produce long-lasting symptoms if the bleeding from the blood vessel progresses quickly, causing a large amount of blood to compress the brain. This can cause permanent brain damage and disability or may even result in death.

Because of the injury to the bleeding blood vessel, blood flow is interrupted and this may also cause a stroke in an area of the brain nearby the subarachnoid bleed. Often, blood vessels in the brain suddenly narrow or close off (spasm) in the days after a subarachnoid hemorrhage, causing a stroke.

What should I expect from a subarachnoid hemorrhage? 

A subarachnoid hemorrhage is an emergency. Some people need emergency surgery to remove large amounts of blood from the brain, while others need to be medically stabilized first and then have surgery in 24-48 hours to remove the blood and stop the source of bleeding by repairing the blood vessel. Not everybody who has a subarachnoid hemorrhage needs surgery. For example, in patients with a ruptured blood vessel in an area that is considered unsafe to operate on or patients who are medically unsafe for surgery, other less invasive treatment options such as coiling of the aneurysm can be considered.

(See treatment of berry aneurysm.) Patients with ruptured subarachnoid hemorrhage most often do not need any surgical intervention and are managed clinically.

The medical care includes blood pressure control, fluid regulation, and electrolyte management to prevent swelling in the brain. Swelling in or near the brain can cause more damage. Medications for seizure prevention are often necessary because blood in the brain may trigger epileptic convulsions.

You should expect close monitoring for at least a few days after a subarachnoid hemorrhage. It is difficult to predict whether there will be long lasting disability and whether a person who has had a subarachnoid hemorrhage will survive.

Often, after the initial medical emergency is controlled, you will need to have rehabilitation to rebuild your physical and mental abilities after the extensive neurological injury that is characteristic of a subarachnoid hemorrhage.

What causes a subarachnoid hemorrhage?

The most common cause of a subarachnoid hemorrhage is the rupture of a defective blood vessel called a brain aneurysm. Often, severely high blood pressure is the trigger that causes a blood vessel to leak or rupture. Find out more about brain aneurysms and brain aneurysm prognosis here.

Are there warning signs before a subarachnoid hemorrhage?

Some people experience warning signs prior to a subarachnoid hemorrhage. These warning signs are the results of tiny blood vessel leaks that may occur prior to a large amount of bleeding. Warning signs include headaches, vision problems, face weakness, body weakness and severe headaches. Not everybody who has a subarachnoid hemorrhage experiences warning signs and some subarachnoid hemorrhages occur suddenly and without warning.


Early Vasospasm after Aneurysmal Subarachnoid Hemorrhage Predicts the Occurrence and Severity of Symptomatic Vasospasm and Delayed Cerebral Ischemia, Jabbarli R, Reinhard M, Shah M, Roelz R, Niesen WD, Kaier K, Taschner C, Weyerbrock A, Van Velthoven V, Cerebrovascular Disease, February 2016

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