A stroke happens when an artery that carries blood from the heart to the brain bursts or is blocked. This means that part of the brain does not get the blood and nutrients it needs, so it starts to die. When this happens, abilities caused by that area of the brain, like memory or muscle control, are lost. There are three main types of stroke.
Ischemic stroke is the most common. It happens when an artery in the brain is blocked, and there are two types:
- Embolic stroke is when a blood clot or plaque forms and moves through the arteries to the brain. Once in the brain, the clot blocks a blood vessel and leads to a stroke.
- Thrombotic stroke is when a blood clot forms inside an artery that takes blood to the brain. This interrupts blood flow and causes a stroke.
Hemorrhagic stroke, less common than ischemic stroke, happens when a blood vessel in the brain bursts and spills blood in or around the brain. There are two main types:
- Intracerebral hemorrhage is when a burst blood vessel bleeds into brain tissue. This causes brain cells to die and part of the brain to stop working correctly.
- Subarachnoid hemorrhage is when a blood vessel bursts near the surface of the brain and blood leaks in between the brain and the skull.
A transient ischemic attack (TIA), or mini-stroke, happens if an artery in the brain or one that goes to the brain is blocked for a short time. This causes temporary numbness, weakness or loss of vision, and it might cause trouble speaking or loss of balance.
Even though blood flow to the brain is only blocked for a short time – usually no more than 5 minutes, a TIA is a medical emergency and a serious warning sign that you might have a stroke.