Subarachnoid hemorrhage

Overview

A subarachnoid hemorrhage is bleeding that occurs in the space between the brain and the thin tissues that cover and protect it, the subarachnoid space. The primary symptom is typically a sudden, severe headache, which is often described as the worst headache one has ever had. This condition most commonly arises when an aneurysm—a balloon–like bulge in a blood vessel—bursts in the brain. It can also be caused by trauma, an arteriovenous malformation (a complex tangle of blood vessels), or other vascular or health problems. Without treatment, a subarachnoid hemorrhage can lead to permanent brain damage or even death.

Symptoms

The primary symptom of a subarachnoid hemorrhage is a thunderclap headache—an extremely intense and sudden onset headache. If you experience a thunderclap headache, it’s crucial to call your emergency hotline or go to the nearest emergency room, especially if accompanied by other symptoms.

Additional symptoms of subarachnoid hemorrhage may include:

• Lowered levels of consciousness and alertness.
• Convulsions.
• Vomiting
• Nauseous.
• Abrupt weakness.
• Numbness in a specific part of your body.
• Stiff neck.
• Lightheadedness.
• Changes in personality and mood, such as irritability and confusion.
• Photophobia, or sensitivity of the eyes to light.
• Changes in vision, such as blind spots, double vision, or momentary blindness in one eye.
• Aches in your muscles, particularly in your shoulders and neck.

Causes

Subarachnoid hemorrhage often results from head trauma, such as from a severe fall or car accident. Another frequent cause is the rupture of a brain aneurysm, which leads to bleeding in the space between the brain and skull. 

A brain aneurysm is a condition where an artery in the brain becomes dilated and can burst, causing bleeding. When a brain aneurysm ruptures spontaneously, without any associated head trauma, it can also cause a subarachnoid hemorrhage (SAH). In fact, about 85% of non–traumatic cases of SAH are due to ruptured brain aneurysms.

Less common causes of SAH include:

• Blood thinner use.
• Bleeding disorders.
• The usage of methamphetamine or cocaine.
• Bleeding from an Arteriovenous Malformation (AVM), a tangle of blood vessels.

Risk Factors

Subarachnoid hemorrhage can affect anyone but is most common in individuals aged between 40 and 60. In older adults, this type of hemorrhage is often due to falls resulting in head injuries. For younger individuals, the leading cause of subarachnoid hemorrhage is typically vehicle accidents.

Factors that increase the likelihood of experiencing subarachnoid hemorrhage include:

• Past history of a brain aneurysm rupture.
• An unruptured aneurysm in your body, either in the brain or somewhere else.
• A strong aneurysm family history.
• Hypertension, or elevated blood pressure.
• Usage of blood thinners, such as warfarin.
• Usage of methamphetamine or cocaine.
• Using cigarettes.
• Overconsumption of alcohol.
• History of polycystic kidney disease
• Ehlers–Danlos syndrome, Fibromuscular Dysplasia (FMD), and other connective tissue diseases.