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Subarachnoid Hemorrhage

What Is a Subarachnoid Hemorrhage?

Subarachnoid hemorrhage (SAH) refers to bleeding within the subarachnoid space, which is the area between the brain and the tissues that cover the brain.

The subarachnoid space is the space where the cerebrospinal fluid circulates, and it’s responsible for protecting your brain from serious injuries by serving as a cushion. A hemorrhage in this space can cause a coma, paralysis, and even death.

This condition can occur quickly, and the key to survival is immediate medical intervention. Call a doctor or 911 as soon as possible if you or someone you know has the symptoms of SAH.

This life-threatening condition is also rare. According to the Brain Aneurysm Foundation, SAH accounts for between 0.01 and 0.08 percent of visits to the emergency room.

Symptoms of SAH


When SAH develops, it has several symptoms. The main symptom is a sudden, severe headache, which is more intense at the base of the skull. Some people may even feel a popping sensation in their head before the hemorrhage begins.

You may also have:

  • neck pain
  • numbness throughout your body
  • shoulder pain
  • seizures
  • confusion
  • irritability
  • sensitivity to light
  • decreased vision
  • nausea
  • vomiting
  • rapid loss of alertness

The symptoms of SAH come on suddenly, and you may lose consciousness quickly. You should get emergency medical attention right away if you experience any of these symptoms combined with a severe headache,

Causes of SAH


SAH is often related to brain aneurysms, which are abnormalities within the brain’s arteries. The most common cause of primary SAH is a congenital berry aneurysm. It’s called a berry aneurysm because it forms a cluster of sac-like pouches in a cerebral vessel that looks like a cluster of berries. These aneurysms swell up and weaken the walls of the arteries over time.

When an aneurysm erupts, it quickly bleeds and forms a clot. This condition is responsible for most SAH cases. Aneurysmal hemorrhage may occur at any age, but it’s most common from age 40 to 65. In some cases, trauma to the brain during an injury can cause aneurysms and result in a subarachnoid hemorrhage.

Other causes of SAH include:

  • bleeding from an arteriovenous malformation (AVM)
  • bleeding disorders
  • use of blood thinners

A serious head injury, such as one that occurs in a car crash or when an older person falls and hits their head, can also lead to an SAH.

Risk Factors for SAH

Risk Factors

SAH can occur at any age, and some people are even born with cerebral aneurysms that can lead to this condition. According to the Internet Stroke Center, women are more likely to develop SAH than men.

One in 50 people is estimated to have an unruptured aneurysm in the United States. You should talk to your doctor about your risk of developing an aneurysm if you have a history of brain aneurysms

If you have aneurysms, it’s important to see your doctor regularly to help figure out your potential for hemorrhaging before SAH develops.

Diagnosing SAH


SAH is often detected during a physical exam. Your doctor may notice that you have a stiff neck and vision problems. This combination often leads to a diagnosis of SAH. You’ll need more testing to find out the severity of the hemorrhage so that you can get proper treatment.

First, your doctor may conduct a CT scan of the head to look for bleeding in your skull. If the results are inconclusive, the doctor may use a contrast dye during the procedure.

Other tests include:

  • an MRI scan, which uses radio waves to get clear, detailed images of the brain
  • a cerebral angiography, which uses an X-ray and injected dye to detect blood flow in the brain
  • a transcranial ultrasound, which detects blood flow in the arteries within the brain

This condition is often misdiagnosed because 73 percent of people don’t get scans.

Treating SAH


Rapid treatment is important to save your life and reduce the possibility of brain damage. Surgery is performed to first clip, or close, the aneurysm and stop future bleeding. It’s then done to more permanently repair the aneurysm.

If your aneurysm is being clipped, a craniotomy is performed and the aneurysm is closed. A craniotomy involves opening the skull to expose the area of involvement. A technique called endovascular coiling may also be used to reduce the risk of further bleeding.

If SAH causes a coma, treatment will include appropriate life support with artificial ventilation, protection of the airways, and placement of a draining tube in the brain to relieve pressure.

If you don’t lose consciousness from the SAH, you’ll still be given strict instructions to prevent post-treatment coma. Bed rest is standard for people recovering from this condition. Your doctor will also ask you to refrain from straining your body or bending over. These actions can increase the pressure on your brain.

Your doctor may prescribe medications to:

  • prevent seizures with phenytoin or other medications
  • regulate blood pressure with medication through an IV
  • prevent artery spasms with nimodipine
  • relieve severe headaches with painkillers and anti-anxiety medications

What Are the Complications of SAH?


Even after SAH treatment, you may be at risk for related complications. The most common complication is called repeated bleeding. This happens when a rupture that has healed itself ruptures again. Repeated bleeding can increase your risk of death. Comas due to SAH can also eventually lead to death.

In some cases, people may experience seizures or strokes following treatment.

How Can I Prevent SAH?


The only way to prevent this condition is to identify potential problems within the brain. Early detection and, in some cases, treatment of a brain aneurysm can prevent a subsequent hemorrhage in the subarachnoid space.

What Is the Long-Term Outlook for SAH?


SAH is a serious condition that can be fatal. The recovery period is long, and you may be at a higher risk of complications if you’re older or have poor overall health.

Treatment isn’t a guarantee. Some people die even after the most aggressive medical interventions. The earlier you seek emergency medical care, the better your chances of survival.

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