Stroke Causes

What is a stroke?

Brief description

A stroke, also known as a cerebrovascular accident, is a condition that occurs when the blood supply to your brain is inhibited. ^1,2 Stroke is known to be the second leading cause of death worldwide and is much more prevalent in developing countries. ¹

There are two common types of strokes: ischemic and hemorrhagic strokes. ¹ You might wonder, what are the differences between these two? Well, an ischemic stroke is due to a lack of blood and oxygen supply to the brain. Meanwhile, hemorrhagic stroke is due to bleeding or leaky blood vessels in the brain. ¹ So, what factors can lead to stroke? What are the causes of stroke? This article will review several stroke causes.

Symptoms

Before diving deep into the topic, let’s start with the symptoms of a stroke. Recognising the signs and symptoms of stroke from the patient’s history and physical presentation is essential to help find which region of the body is affected by the stroke. ²

Common symptoms of strokes include:

1. Hemiparesis: inability to move one side of your body
2. Sensory deficits
3. Diplopia: you see two images when you look at one object
4. Dysarthria: difficulty in speaking due to brain damage 
5. Facial droop: also called Bell’s palsy, is a lack of movement on one side of your face

However, some patients with ischaemic stroke might experience a sudden onset of ataxia and vertigo. ² Ataxia is a group of conditions that affect your balance, speech and coordination. Meanwhile, vertigo is when you feel dizzy, and the world around you is spinning. Patients need to establish when they start to display the symptoms of ischaemic stroke as it is vital for decisions on subsequent therapy. ²

On the other hand, patients with a hemorrhagic stroke might display symptoms commonly attributed to increased intracranial pressure, such as nausea, vomiting, headache or blurred vision. ² Thus, getting yourself checked once you show the signs is essential. 

Causes

Can be different for the 2 types of strokes

Then, what factors can lead to stroke? The causes of strokes can be different for the 2 types of strokes. 

Cause of ischaemic strokes

Blood clot in one of the brain blood vessels

Atherosclerosis is a condition where sticky substances called plaques build up inside your blood  vessels. Over time, plaque build-up will constrict the blood vessels and form blockages, preventing the blood flow to some parts of the brain.^1,3 Ischaemic strokes are due to a thrombotic event that causes a decrease in blood supply to the brain. ³ In thrombosis, the blood vessels become narrow due to atherosclerosis, affecting the blood flow to the brain. ^1,3

Another factor that can lead to ischaemic stroke is embolic events. ³ Embolic events occur when blood clots from other parts of the body block the blood flow to the brain. ³ The most common source of blood clots is the heart. ³ Embolic events can lead to severe stress and cell death. ¹

Causes of hemorrhagic strokes

Thinned blood vessels in the brain

One of the factors that might lead to hemorrhagic strokes is a brain aneurysm.⁴ A brain aneurysm is a bulge or ballooning of blood vessels due to a weakening blood vessel wall in the brain. If the bulge expands and the blood vessel wall in the brain becomes thin, it will rupture and bleed around the brain, which can lead to a hemorrhagic stroke. ⁵

Brain aneurysms often develop over time due to part of the vessel walls becoming less elastic as a result of the normal aging process, high blood pressure and smoking. ⁴

High blood pressure

High blood pressure, also medically known as hypertension, is a common cause of hemorrhagic strokes.⁶ The recommendation of the blood pressure reading for a stroke patient is less than 140/90 mmHg. ⁷ Long-term hypertension can reduce the elasticity of your blood vessels. ⁷ Furthermore, hypertension can damage and rupture your blood vessels, leading to hemorrhagic stroke. ^6,7

Out of all the risk factors associated with stroke, hypertension is modifiable, meaning you can reduce your blood pressure by changing your lifestyle. ⁷ Lifestyle measures that can help to reduce your blood pressure are weight loss, salt restriction, and eating more fruits and vegetables (for example, the Mediterranean diet).⁷ Every 10mmHg decrease in blood pressure is associated with a 1/3rd reduction in the risk of stroke. ⁷

Conclusion

The article mainly summarizes the causes and symptoms of two types of strokes; ischaemic stroke and hemorrhagic stroke. Both strokes share some symptoms, but they also display different signs. However, these signs might vary depending on individual patients. Furthermore, the causes are different for both types of strokes. Blood clotting is one of the causes associated with ischaemic stroke. Meanwhile, thinning of blood vessels and hypertension is one of several causes related to hemorrhagic stroke.