Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention

Definition

Subarachnoid hemorrhage is a type of stroke that occurs when a blood vessel ruptures. Blood quickly fills the area immediately surrounding the brain and spinal cord (called the subarachnoid space). This space contains the cerebrospinal fluid. The fluid cushions and bathes the brain and spinal cord. This life-threatening condition requires emergency medical care. The hemorrhage may increase the pressure around the brain. It can interfere with the brain's ability to function.

Subarachnoid Hemorrhage

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Causes

Subarachnoid hemorrhage occurs in about 30,000 Americans each year. It is most common in people aged 35-65 years. This type of hemorrhage is usually caused by:

  • Serious head injury ( trauma)
  • Rupture of cerebral aneurysms and other blood vessel deformities (spontaneous subarachnoid hemorrhage)—These are usually present since birth.
  • Bleeding disorders
  • Drug use (especially cocaine and amphetamines)
  • Brain tumors—Tumors can contain abnormal blood vessels. Tumors may not be detected until after they bleed.

Risk Factors

These risk factors increase your chance of developing subarachnoid hemorrhage. Tell your doctor if you have any of these risk factors:

Symptoms

If you have any of these symptoms, do not assume it is due to subarachnoid hemorrhage. These symptoms may be caused by other conditions. Tell your doctor if you have any of these:

  • A very sudden, excruciating headache (frequently described as the "worst headache of my life”)
  • Brief loss of consciousness
  • Seizures
  • Nausea and vomiting
  • Weakness on one side of your body
  • Unexplained numbness or tingling
  • Slurred speech or other speech disturbance
  • Visions problems, such as double vision, blind spots, or temporary vision loss on one side
  • Stiff neck or shoulder pain
  • Confusion

If you experience any one of these symptoms, get emergency medical care right away.

Diagnosis

Your doctor will ask about your symptoms and medical history. A physical exam will also be done.

Tests may include the following:

  • CT scan of the head —a type of x-ray that uses a computer to make pictures of structures inside the head
  • Lumbar puncture (spinal tap)—a procedure to determine if there is blood in the cerebrospinal fluid
  • Angiogram —a type of x-ray that takes images of the brain's blood vessels after dye is injected in the bloodstream
  • CT angiogram—a type of x-ray that looks at the blood vessels in the head and neck
  • MRI scan —a test that uses magnetic waves to make pictures of structures inside the brain and neck

Treatment

Subarachnoid hemorrhage is a serious condition. It requires initial treatment in the intensive care unit. Despite treatment, approximately 25%-30% of patients with this condition die.

The aim of treatment is to stop the bleeding, limit damage to the brain, and reduce the risk of recurrence. If bleeding results from a cerebral aneurysm, a doctor will usually attempt to stop it using various techniques. Patients receive medicines to ensure proper blood flow to the rest of the brain. Treatment will often take place in an intensive care unit where patients can be closely monitored. Absolute bed rest is needed to prevent additional bleeding. Once the situation is stabilized, patients undertake a vigorous rehabilitation program.

If you are diagnosed with a subarachnoid hemorrhage, follow your doctor's instructions.

Prevention

Aneurysms present since birth cannot be prevented. Since they are so rare, doctors do not recommend screening for them. However, not smoking and controlling blood pressure can theoretically reduce the risk of a rupture if an aneurysm exists. If an unruptured aneurysm is discovered by chance in a young person, the doctor may do surgery.

Wearing a seatbelt and using a helmet can reduce the risk of subarachnoid hemorrhage from head trauma.