The causes of stroke can be broadly classified into two categories. A blockage or reduction in blood supply in a part of the brain leads to an ischemic stroke. In this scenario, the affected brain tissue is deprived of oxygen and nutrients, initiating the death of brain cells within minutes. On the other hand, a hemorrhagic stroke is characterised by the leakage or bursting of a blood vessel in the brain, causing bleeding that exerts pressure on brain cells, resulting in damage.
What are the causes of stroke?
The classification of strokes is typically based on their causes, and they can be categorised into three main types:
The most common type of stroke, due to blockage of brain blood vessels, often caused by fatty deposits or particles from the heart.
Initial research suggests a possible link between COVID-19 and a higher risk of ischemic stroke. However, further, more extensive studies are needed to confirm these findings.
Hemorrhagic strokes result from conditions like lack of control over high blood pressure, overuse of blood thinners, weak spots in blood vessel walls (aneurysms), head trauma, protein deposits causing vessel weakness (cerebral amyloid angiopathy), and hemorrhage triggered by an ischemic stroke.
- Transient ischemic attack (TIA):
TIA is a brief episode resembling stroke symptoms but without lasting damage, contrasting a stroke. It occurs due to a temporary reduction in blood supply to a part of the brain, with a duration as short as five minutes. Commonly known as a ministroke, immediate medical attention is essential.
Many medical factors can increase the risk of stroke:
- High blood pressure.
- Cigarette smoking or secondhand smoke exposure.
- High cholesterol.
- Diabetes.
- Obstructive sleep apnea.
- Cardiovascular disease, including heart failure, heart defects, heart infection or irregular heart rhythm, such as atrial fibrillation.
- Personal or family history