A health condition in which bleeding occurs below one of the thin layers that cover and protect the brain is called a subarachnoid hemorrhage (SAH). In general, this condition is a medical emergency that needs immediate treatment. Commonly, it is caused by head trauma or a ruptured brain aneurysm. The most common symptom of SAH is a sudden and severe headache.
Normally, the brain has 3 membrane layers or coverings (also known as meninges) that lie between the skull and brain tissue. The first (outermost) layer of the meninges is called dura mater, the middle layer is known as arachnoid, and the layer closest to the brain is called pia mater. This disorder occurs when bleeding appears below the middle layer (arachnoid). When SAH occurs, people often experience a thunderclap headache, which is a very painful headache. People who have experienced this symptom describe it as the worst headache of their lives.
About 10 to 14 out of 100,000 people experience a SAH each year in the United States.
Symptoms
While the primary symptom of SAH is a thunderclap headache, it may also cause other symptoms. In any case, if you experience a very intense and painful headache that occurs suddenly, call 911 or go to the nearest emergency room (ER). Check below for other symptoms of subarachnoid hemorrhage:
- Reduced consciousness and alertness
- Neck stiffness
- Nausea
- Vomiting
- Mood and personality changes (such as confusion, irritability, and others)
- Dizziness
- Increased sensitivity to light
- Muscle aches, especially in the shoulders and neck
- Numbness
- Seizures
- Vision changes (including blind spots, double vision, temporary loss of vision in one eye, and others)
If any of the previous symptoms occur, do not hesitate to see a doctor.
Causes
In most cases, people develop this condition due to head trauma that occurs due to a serious fall or a car accident. The second most common cause of SAH is a brain aneurysm bursting. A brain aneurysm is a ballooning of an artery that supplies the brain with oxygen-rich blood. For instance, about 85% of non-traumatic SAH occur due to a ruptured brain aneurysm. Check below for other less common causes of SAH:
- Bleeding disorders
- The use of blood thinners (also called anticoagulants)
- Use of illegal drugs (including cocaine, methamphetamine, and others)
- Arteriovenous malformations (AVMs)
Risk Factors
While this condition can affect anyone, it mostly occurs in people between the ages of 40 and 60. Therefore, doctors have identified some factors that could increase your risk of developing SAH. Check below some of them:
- An unruptured aneurysm in the brain or another part of the body
- Smoking
- Previous ruptured brain aneurysm
- Hypertension (high blood pressure)
- Connective tissue disorders, including fibromuscular dysplasia (FMD), Ehlers-Danlos syndrome, and others
- A medical history of polycystic kidney disease
- Misuse of alcohol or recreational drugs
- A family history of aneurysms
What Are The Long-term Effects of Subarachnoid Hemorrhage?
While there are some complications that occur right after SAH happens, some people recover, but with disabilities (long-term complications). Immediate complications of SAH include:
- Vasospasm
- Seizures
- Hydrocephalus
- Hemorrhaging again after initial treatment
- Increased intracranial pressure
- Cerebral infarction (also called ischemic stroke)
- Death
- Brain herniation
Check below some long-term effects of SAH:
- Physical problems – This disorder can cause physical difficulties, including sleepiness, fatigue (extreme tiredness), numbness, weakness, swallowing problems, and loss of balance.
- Cognitive (thinking) issues – This disorder may lead to cognitive dysfunction, including memory loss, difficulty concentrating, and difficulty performing complex tasks.
- Speech difficulties – Subarachnoid hemorrhage may cause slurred or slowed speech or difficulty finding words to express yourself.
- Mental disorders – Some people may develop depression, generalized anxiety, or post-traumatic stress disorder (PTSD).
In most cases, long-term complications are managed with the following treatments. These include physical therapy, occupational therapy, speech therapy, and psychotherapy (also known as talk therapy).
How to Prevent Subarachnoid Hemorrhage?
While the majority of SAHs occur due to head injuries, you can prevent this disorder by avoiding head trauma or ruptured brain aneurysms. To reduce the risk of head trauma, you can wear a helmet when riding a bike or motorcycle or when playing high-risk sports. It is also important to follow traffic laws.
People may also develop SAH due to a ruptured aneurysm. To reduce the risk of aneurysms, check the following tips:
- Manage chronic health conditions, including high blood pressure, diabetes, and others
- Quit smoking
- Regularly perform physical exercise because it helps get and maintain a healthy weight
- Adopt a balanced diet
- Avoid alcohol and illegal drugs (such as cocaine)
Diagnosis
Usually, when doctors suspect SAH, they order a CT (computed tomography) scan. This test uses X-rays and a computer to produce cross-sectional images of tissue in the body. It can identify a subarachnoid hemorrhage. Another test used to determine whether you have SAH or not is a CT angiography (CTA) that uses contrast dye to see how blood flows through the arteries.
Check below some tests often performed by doctors when CT scans are negative:
- Lumbar puncture (also called spinal tap) – During this test, doctors will take a small sample of the cerebrospinal fluid (CSF) for testing. They will check for Xanthochromia, which often indicates subarachnoid hemorrhage.
- Brain MRI (magnetic resonance imaging) – This is another imaging test used to get detailed images of the brain and surrounding tissue.
Furthermore, about 80% of all SAH cases are caused by a ruptured aneurysm. Thus, doctors may perform a cerebral angiogram to get images of the brain’s arteries and treat aneurysms.
Treatment
This is a life-threatening and emergency disorder that is often treated in the intensive care unit (ICU) in a hospital with neurological expertise. In general, the treatment goal is to save your life, repair the cause of the bleeding, ease the symptoms, and prevent serious complications (such as vasospasm, hydrocephalus, and permanent damage to the brain). Check below some treatments often recommended by doctors for people with subarachnoid hemorrhage:
- A draining tube that is inserted into the brain to relieve pressure
- Medicines to reduce swelling in the skull
- IV medicines to manage blood pressure
- Medicines to prevent artery spasms and seizures
- Pain relievers and anti-anxiety medicines to reduce the severity of headaches
Some people need surgery to treat SAH and its cause. During this procedure, surgeons will remove large collections of blood or repair the aneurysm that caused the condition.
Frequently Asked Questions
What is the difference between a subarachnoid hemorrhage and a subdural hematoma?
While these conditions are both types of bleeding in the brain, there are some differences between them. Subdural hematomas often occur due to a tear in a blood vessel (mostly in a vein), which causes blood to leak out of the torn vessel into the space below the dura mater membrane layer. However, in people with SAH, the blood is leaking into the space below the arachnoid layer. In general, both are medical emergencies and cause similar symptoms.
How long are hospital stays for subarachnoid hemorrhage (SAH)?
The length of stay in the hospital is different among people because it depends on several factors. These include the severity and cause of SAH, existing health problems, age, and preferences. In most cases, people with SAH stay in the hospital for 10 to 20 days.
What is the life expectancy after a subarachnoid hemorrhage?
The life expectancy varies based on the severity and how fast the affected person is diagnosed and treated. Generally, the one-year mortality rate of untreated SAH is up to 65%. It means that about 65% of people who do not get treatment die within 12 months after the first episode. With early diagnosis and proper treatment, the one-year mortality rate decreases to 18%. Ask your healthcare provider if you have additional questions.
