Condition 101 About Subarachnoid Hemorrhage

What is the definition of Subarachnoid Hemorrhage?

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 bleeding is an emergency and prompt medical attention is needed.

What are the alternative names for Subarachnoid Hemorrhage?

Hemorrhage - subarachnoid; Subarachnoid bleeding

What are the causes for Subarachnoid Hemorrhage?

Subarachnoid hemorrhage can be caused by:

  • Bleeding from a tangle of blood vessels called an arteriovenous malformation (AVM)
  • Bleeding disorder
  • Bleeding from a cerebral aneurysm (weak area in the wall of a blood vessel that causes the blood vessel to bulge or balloon out)
  • Head injury
  • Unknown cause (idiopathic)
  • Use of blood thinners

Subarachnoid hemorrhage caused by injury is often seen in the older people who have fallen and hit their head. Among the young, the most common injury leading to subarachnoid hemorrhage is motor vehicle crashes.

Risks include:

  • Unruptured aneurysm in the brain and other blood vessels
  • Fibromuscular dysplasia (FMD) and other connective tissue disorders
  • High blood pressure
  • History of polycystic kidney disease
  • Smoking
  • Use of illicit drugs such as cocaine and methamphetamine
  • Use of blood thinners such as warfarin

A strong family history of aneurysms may also increase your risk.

What are the symptoms for Subarachnoid Hemorrhage?

The main symptom is a severe headache that starts suddenly (often called thunderclap headache). It is often worse near the back of the head. Many people often describe it as the "worst headache ever" and unlike any other type of headache pain. The headache may start after a popping or snapping feeling in the head.

Other symptoms:

  • Decreased consciousness and alertness
  • Eye discomfort in bright light (photophobia)
  • Mood and personality changes, including confusion and irritability
  • Muscle aches (especially neck pain and shoulder pain)
  • Nausea and vomiting
  • Numbness in part of the body
  • Seizure
  • Stiff neck
  • Vision problems, including double vision, blind spots, or temporary vision loss in one eye

Other symptoms that may occur with this disease:

  • Eyelid drooping
  • Pupil size difference
  • Sudden stiffening of back and neck, with arching of the back (opisthotonos; not very common)

What are the current treatments for Subarachnoid Hemorrhage?

The goals of treatment are to:

  • Save your life
  • Repair the cause of bleeding
  • Relieve symptoms
  • Prevent complications such as permanent brain damage (stroke)

Surgery may be done to:

  • Remove large collections of blood or relieve pressure on the brain if the hemorrhage is due to an injury
  • Repair the aneurysm if the hemorrhage is due to an aneurysm rupture

If the person is critically ill, surgery may have to wait until the person is more stable.

Surgery may involve:

  • Craniotomy (cutting a hole in the skull) and aneurysm clipping, to close the aneurysm
  • Endovascular coiling: placing coils in the aneurysm and stents in the blood vessel to cage the coils reduces the risk of further bleeding

If no aneurysm is found, the person should be closely watched by a health care team and may need more imaging tests.

Treatment for coma or decreased alertness includes:

  • Draining tube placed in the brain to relieve pressure
  • Life support
  • Methods to protect the airway
  • Special positioning

A person who is conscious may need to be on strict bed rest. The person will be told to avoid activities that can increase pressure inside the head, including:

  • Bending over
  • Straining
  • Suddenly changing position

Treatment may also include:

  • Medicines given through an IV line to control blood pressure
  • Medicine to prevent artery spasms
  • Painkillers and anti-anxiety medicines to relieve headache and reduce pressure in the skull
  • Medicines to prevent or treat seizures
  • Stool softeners or laxatives to prevent straining during bowel movements
  • Medicines to prevent seizures

What is the outlook (prognosis) for Subarachnoid Hemorrhage?

How well a person with subarachnoid hemorrhage does depends on a number of different factors, including:

  • Location and amount of bleeding
  • Complications

Older age and more severe symptoms can lead to a poorer outcome.

People can recover completely after treatment. But some people die, even with treatment.

What are the possible complications for Subarachnoid Hemorrhage?

Repeated bleeding is the most serious complication. If a cerebral aneurysm bleeds for a second time, the outlook is much worse.

Changes in consciousness and alertness due to a subarachnoid hemorrhage may become worse and lead to coma or death.

Other complications include:

  • Complications of surgery
  • Medicine side effects
  • Seizures
  • Stroke

When should I contact a medical professional for Subarachnoid Hemorrhage?

Go to the emergency room or call the local emergency number (such as 911) if you or someone you know has symptoms of a subarachnoid hemorrhage.

How do I prevent Subarachnoid Hemorrhage?

The following measures may help prevent subarachnoid hemorrhage:

  • Stopping smoking
  • Treating high blood pressure
  • Identifying and successfully treating an aneurysm
  • Not using illicit drugs


Mayer SA. Hemorrhagic cerebrovascular disease. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 408.

Szeder V, Tateshima S, Duckwiler GR. Intracranial aneurysms and subarachnoid hemorrhage. In: Daroff RB, Jankovic J, Mazziotta JC, Pomeroy SL, eds. Bradley's Neurology in Clinical Practice. 7th ed. Philadelphia, PA: Elsevier; 2016:chap 67.

Top Global Doctors For Subarachnoid Hemorrhage

Latest Advances On Subarachnoid Hemorrhage

  • Condition: Ruptured Aneurysms
  • Journal: Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia
  • Treatment Used: Cerebrovascular Bypass
  • Number of Patients: 40
  • Published —
This study tested the safety and efficacy of using cerebrovascular bypass to treat patients with ruptured aneurysms.
  • Condition: Brain Aneurysm
  • Journal: Zhurnal voprosy neirokhirurgii imeni N. N. Burdenko
  • Treatment Used: Minimally Invasive Microsurgery
  • Number of Patients: 394
  • Published —
This study tested the safety and efficacy of using minimally invasive microsurgery to treat patients with brain aneurysms.

Clinical Trials For Subarachnoid Hemorrhage

Clinical Trial
  • Status: Not yet recruiting
  • Phase: Phase 2
  • Intervention Type: Drug
  • Participants: 160
  • Start Date: March 1, 2021
Effect of Xenon on Brain Injury, Neurological Outcome and Survival in Patients After Aneurysmal Subarachnoid Hemorrhage
Clinical Trial
  • Status: Not yet recruiting
  • Phase: Phase 2
  • Intervention Type: Drug
  • Participants: 120
  • Start Date: February 2021
Deferoxamine In the Treatment of Aneurysmal Subarachnoid Hemorrhage (DISH)