Stroke is a medical condition characterised by interruption of blood supply to the brain. This may happen of a blood vessel is blocked and stops blood from entering the brain or when there is a bleeding.
There are three types of stroke: ischemic stroke, intracerebral haemorrhage and subarachnoid haemorrhage.
The ischemic stroke is the most common type of stroke. Almost 80% of all stroke cases are of ischemic stroke. The ischemic stroke occurs when a blood vessel in the brain is blocked. Regular supply of fresh blood is vital to brains health. If a blood vessel is blocked, the brain cells can not receive blood rich of oxygen and nutrients and they stop working. If the blood supply is stopped for more than a few minutes the brain cells start dying. The ischemic stroke may be caused by many reasons but the most common one is narrowing the arteries of the neck and the head. If the blood vessels become too narrow blood cells start to collect and form blood clogs. These clogs may block the blood vessel or dislodge and get closer to the brain and again clog the blood vessel. An ischemic stroke may be also caused by drug abuse, injury, or disorders of blood clotting.
The intracerebral haemorrhage stroke occurs when a blood vessel inside the brain bursts. In this case blood just leaks out causing high pressure to the cells that surround the leak. If the blood leaks out rapidly there might be a severe brain damage and even death. The intracerebral haemorrhage usually occurs in selected parts of the brain and that is why the damages may be to selected functions of the body. The intracerebral haemorrhage stroke is caused by high blood pressure and it may occur in people of all ages including children. Overall around 12% of all strokes are of this type.
The subarachnoid haemorrhage occurs when a blood vessel just outside the brain bursts causing blood to leak out. The area of the skull surrounding the brain fills with blood and that is why people experiencing subarachnoid haemorrhage may feel sudden severe headache, neck pain, and nausea or vomiting. This kind of stoke is typical for people of all ages, especially for young adults and teenagers. It is more common for women than for men and is caused by a disease of the arteries. It may develop from birth or in childhood and grow very slowly.