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.
Causes
Subarachnoid hemorrhage can be caused by:
- Bleeding from a tangle of blood vessels called an arteriovenous malformation (AVM)
Arteriovenous malformation
A cerebral arteriovenous malformation (AVM) is an abnormal connection between the arteries and veins in the brain that usually forms before birth....
Read Article Now Book Mark Article - 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)
Cerebral aneurysm
An aneurysm is a weak area in the wall of a blood vessel that causes the blood vessel to bulge or balloon out. When an aneurysm occurs in a blood ve...
Read Article Now Book Mark Article - Head injury
- Unknown cause (idiopathic)
- Use of blood thinners
Subarachnoid hemorrhage caused by head injury in older people is often due to falls. Among the young, the most common injury leading to subarachnoid hemorrhage is motor vehicle crashes. When caused by trauma, subarachnoid hemorrhage commonly occurs with other types of bleeding in the head.
Risks include:
- Unruptured aneurysm in the brain and other blood vessels
- Fibromuscular dysplasia (FMD) and other connective tissue and autoimmune disorders
- High blood pressure
- History of polycystic kidney disease
Polycystic kidney disease
Polycystic kidney disease (PKD) is a kidney disorder passed down through families. In this disease, many cysts form in the kidneys, causing them to ...
Read Article Now Book Mark Article - 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.
Symptoms
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
Decreased consciousness
Decreased alertness is a state of reduced awareness and is often a serious condition. A coma is the most severe state of decreased alertness from whi...
Read Article Now Book Mark Article - Eye discomfort in bright light (photophobia)
- Mood and personality changes, including confusion and irritability
Confusion
Confusion is the inability to think as clearly or quickly as you normally do. You may feel disoriented and have difficulty paying attention, remembe...
Read Article Now Book Mark Article - Muscle aches (especially neck pain and shoulder pain)
- Nausea and vomiting
- Numbness in part of the body
- Seizure
Seizure
A seizure is the physical changes in behavior that occurs during an episode of specific types of abnormal electrical activity in the brain. The term ...
Read Article Now Book Mark Article - 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
Eyelid drooping
Eyelid drooping is excess sagging of the upper eyelid. The edge of the upper eyelid may be lower than it should be (ptosis) or there may be excess b...
Read Article Now Book Mark Article - Pupil size difference
Pupil size difference
Anisocoria is unequal pupil size. The pupil is the black part in the center of the eye. It gets larger in dim light and smaller in bright light....
Read Article Now Book Mark Article - Sudden stiffening of back and neck, with arching of the back (opisthotonos; not very common)
Opisthotonos
Opisthotonos is a condition in which a person holds their body in an abnormal position. The person is usually rigid and arches their back, with thei...
Read Article Now Book Mark Article
Exams and Tests
Signs include:
- A physical exam may show a stiff neck.
- A brain and nervous system exam may show signs of decreased nerve and brain function (focal neurologic deficit).
Neurologic deficit
A neurologic deficit refers to abnormal neurologic function of a body area. This altered function is due to injury of the brain, spinal cord, muscle...
Read Article Now Book Mark Article - An eye exam may show decreased eye movements which may indicate damage to the cranial nerves (in milder cases, an eye exam may show no problems).
If your doctor thinks you have a subarachnoid hemorrhage, a head CT scan (without contrast dye) will be done right away. In some cases, the scan is normal, especially if there has only been a small bleed. If the CT scan is normal, a lumbar puncture (spinal tap) may be done. Additional CT scans may be needed for further confirmation.
Head CT scan
A head computed tomography (CT) scan uses many x-rays to create pictures of the head, including the skull, brain, eye sockets, and sinuses.
Read Article Now Book Mark ArticleSpinal tap
Cerebrospinal fluid (CSF) collection is a test to look at the fluid that surrounds the brain and spinal cord. CSF acts as a cushion, protecting the b...
Read Article Now Book Mark ArticleOther tests that may be done include:
- Cerebral angiography of blood vessels of the brain
Cerebral angiography
Cerebral angiography is a procedure that uses a special dye (contrast material) and x-rays to see how blood flows through the brain.
Read Article Now Book Mark Article - CT scan angiography (using contrast dye)
- Transcranial Doppler ultrasound, to look at blood flow in the arteries of the brain
- Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) (occasionally)
Magnetic resonance angiography
Magnetic resonance angiography (MRA) is an MRI exam of the blood vessels. Unlike traditional angiography that involves placing a tube (catheter) int...
Read Article Now Book Mark Article - Blood tests to check for bleeding disorders
Treatment
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
Craniotomy
Brain surgery is an operation to treat problems in the brain and surrounding structures.
Read Article Now Book Mark Article - Endovascular coiling: placing coils in the aneurysm and stents in the blood vessel to cage the coils reduces the risk of further bleeding
Endovascular coiling
Endovascular embolization is a procedure to treat abnormal blood vessels in the brain and other parts of the body. It is an alternative to open surg...
Read Article Now Book Mark ArticleStents
A stent is a tiny tube placed into a hollow structure in your body. This structure can be an artery, a vein, or another structure, such as the tube ...
Read Article Now Book Mark Article
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
- Special medicines to decrease swelling in the skull
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
IV line
Intravenous means "within a vein. " Most often it refers to giving medicines or fluids through a needle or tube inserted into a vein. This allows th...
Read Article Now Book Mark Article - Medicine to prevent artery spasms
- Painkillers and anti-anxiety medicines to relieve headache
- Medicines to prevent or treat seizures
- Stool softeners or laxatives to prevent straining during bowel movements
- Medicines to prevent seizures
Outlook (Prognosis)
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.
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.
Coma
Decreased alertness is a state of reduced awareness and is often a serious condition. A coma is the most severe state of decreased alertness from whi...
Read Article Now Book Mark ArticleOther complications include:
- Complications of surgery
- Medicine side effects
- Seizures
- Stroke
Stroke
A stroke occurs when blood flow to a part of the brain stops. A stroke is sometimes called a "brain attack. " If blood flow is cut off for longer th...
Read Article Now Book Mark Article
When to Contact a Medical Professional
Go to the emergency room or call 911 or the local emergency number if you or someone you know has symptoms of a subarachnoid hemorrhage.
Prevention
The following measures may help prevent subarachnoid hemorrhage:
- Stopping smoking
- Treating high blood pressure
- Identifying and successfully treating an aneurysm
- Not using illicit drugs
Reviewed By
Joseph V. Campellone, MD, Department of Neurology, Cooper Medical School of Rowan University, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
Mayer SA. Hemorrhagic cerebrovascular disease. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 380.
Szeder V, Tateshima S, Jahan R, Saver JL, Duckwiler GR. Intracranial aneurysms and subarachnoid hemorrhage. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 67.