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.

Alternative Names

Hemorrhage - subarachnoid


Subarachnoid hemorrhage can be caused by:

Injury-related subarachnoid hemorrhage is often seen in the elderly who have fallen and hit their head. Among the young, the most common injury leading to subarachnoid hemorrhage is motor vehicle crashes.

Subarachnoid hemorrhage caused by a cerebral aneurysm that breaks open (ruptures) occurs in about 40 - 50 out of 100,000 people over age 30. Subarachnoid hemorrhage due to rupture of a cerebral aneurysm is most common in persons ages 20 to 60. It is slightly more common in women than men.

Risks include:

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


The main symptom is a severe headache that starts suddenly and is often worse near the back of the head. Patients 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:

Other symptoms that may occur with this disease:

Exams and Tests

Signs include:

If your doctor thinks you may have a subarachnoid hemorrhage, a head CT scan (without contrast dye) should be done right away. In 5 - 10% of cases, the scan may be normal, especially if there has only been a small bleed. If the CT scan is normal, a lumbar puncture (spinal tap) must be performed.

Other tests that may be done include:


The goals of treatment are to:

Surgery may be done to:

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

Surgery may involve:

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:

A person who is 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:

Treatment may also include:

Outlook (Prognosis)

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

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

People can recover completely after treatment, but some people may die even with aggressive treatment.

Possible Complications

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:

When to Contact a Medical Professional

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


Identifying and successfully treating an aneurysm can prevent subarachnoid hemorrhage.


Selman WR, Hsu D, Tarr RW, Ratcheson RA. Vascular diseases of the nervous system: intracranial aneurysms and subarachnoid hemorrhage. In: Bradley WG, Daroff RB, Fenichel GM, Jankovic J, eds. Neurology in Clinical Practice. 5th ed. Philadelphia, Pa: Butterworth-Heinemann Elsevier; 2008:chap 55C.

Zivin J. Hemorrhagic cerebrovascular disease. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 432.

Reinhardt MR. Subarachnoid hemorrhoid. J Emerg Nurs. 2010;36(4):327-329.

Rabinstein AA, Lanzino G, Wijdicks EF. Multidisciplinary management and emerging therapeutic strategies in aneurysmal subarachnoid hemorrhage. Lancet Neurol. 2010;9(4):504-519.

Review Date: 2/5/2011
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by Joseph V. Campellone, MD, Division of Neurology, Cooper University Hospital, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.