Subarachnoid Hemorrhage – Symptoms and Causes

ByJanis Updated

Overview

A subarachnoid hemorrhage is a type of stroke that requires immediate medical attention. It occurs when blood leaks into the space between the brain and its protective covering.

The most notable sign is an extremely severe headache that comes on suddenly. Many patients describe it as the most intense headache they’ve ever experienced. Other symptoms may include:

  • Nausea
  • Vomiting
  • Stiff neck
  • Sensitivity to light
  • Confusion

The most common cause is a ruptured aneurysm (a bulge in a blood vessel). Other potential causes include:

Cause Description
Head trauma Injury that damages brain blood vessels
Arteriovenous malformation Abnormal tangle of blood vessels
Blood vessel disorders Various conditions affecting vascular health

Without prompt treatment, a subarachnoid hemorrhage can result in permanent brain damage or death. The severity of this condition cannot be overstated – it represents a true medical emergency requiring immediate medical intervention.

Signs and Symptoms

A subarachnoid hemorrhage typically causes a severe headache that appears suddenly. This headache reaches maximum intensity almost immediately. Many patients describe it as the most intense headache they have ever experienced.

Other common symptoms include:

  • Feeling sick to your stomach (nausea)
  • Throwing up (vomiting)
  • Pain or stiffness in the neck
  • Problems with vision
  • Briefly losing consciousness

When to Get Medical Help

Seek immediate medical attention if you experience a sudden, extremely severe headache or any of the other symptoms mentioned above. This is particularly important if you have a known brain aneurysm or have recently injured your head.

If someone near you complains about a terrible, sudden headache or loses consciousness, call emergency services right away. Don’t wait to see if symptoms improve—quick treatment can make a significant difference in recovery outcomes.

Causes

When blood leaks into the space between the brain and its covering tissues (subarachnoid space), several factors may be responsible:

  • Ruptured Brain Aneurysm: The most frequent cause is a burst bulge in a brain blood vessel. These balloon-like weak spots can tear open, releasing blood around the brain.
  • Traumatic Head Injuries – Accidents, falls, or violent incidents that damage the head can tear blood vessels and cause bleeding in this sensitive area.
  • Other possible causes include:
    • Arteriovenous malformations (AVMs) – abnormal tangles of blood vessels that can rupture.
    • Vasculitis – inflammation of blood vessels that makes walls thicker and narrower, potentially leading to clots or aneurysms.

Risk Factors

Several factors can increase a person’s chances of having a subarachnoid hemorrhage. These factors fall into two categories: those you cannot change and those you can control.

Uncontrollable Risk Factors

  • Age and Gender: People between ages 55 and 60 face a higher risk of aneurysm-related subarachnoid hemorrhage. Women in their 50s and 60s are particularly vulnerable.
  • Family History: Having a blood-related first-degree relative (parent, sibling, or child) with a brain aneurysm increases your risk significantly.
  • Genetic Conditions: Certain health conditions can raise your risk, including:
    • Ehlers-Danlos syndrome
    • Marfan syndrome
    • Neurofibromatosis type 1
    • Polycystic kidney disease

If you have two or more first-degree relatives with brain aneurysms or have experienced a previous subarachnoid hemorrhage, doctors may recommend screening tests.

Controllable Risk Factors

You can take steps to reduce your risk by addressing these factors:

  • High Blood Pressure: Uncontrolled hypertension puts extra stress on blood vessel walls.
  • Tobacco Use: Smoking damages blood vessels and increases the risk of aneurysm formation and rupture.
  • Alcohol Misuse: Heavy drinking can raise blood pressure and contribute to blood vessel damage.
  • Drug Use: Stimulants like cocaine and methamphetamine can cause sudden blood pressure spikes that may trigger bleeding.
Risk Factor Why It Matters
High Blood Pressure Weakens blood vessel walls over time
Smoking Damages blood vessels and raises blood pressure
Alcohol Misuse Can cause hypertension and blood vessel inflammation
Stimulant Drugs Create dangerous blood pressure spikes

While you cannot change your age, gender, or genetic makeup, you can work with your doctor to manage controllable factors.

For those with a strong family history, healthcare providers may recommend imaging tests to check for unruptured aneurysms. These tests might include an MRI or CT angiogram to examine the blood vessels in your brain.

Lifestyle changes can make a big difference in reducing your risk:

  • Take blood pressure medications as prescribed
  • Quit smoking
  • Limit alcohol consumption
  • Avoid recreational drugs

Regular check-ups with your doctor are essential if you have any risk factors. This is especially true for people with genetic conditions that affect blood vessel strength.

Health Writer

Janis's areas of expertise include nutrition, exercise, stress management, and mental health. She is passionate about educating and empowering people to take control of their health and make positive changes that can last a lifetime. Janis believes that small, sustainable changes are the key to long-term success, and she works with her clients to develop personalized plans that fit their individual needs and lifestyles.