A transient ischaemic attack (TIA), which is also known as a mini-stroke, occurs when the supply of blood to the brain is interrupted for a short time. The symptoms of TIA can last just a few minutes but a mini-stroke is frequently associated with a later acute stroke, so it is a good idea to get urgent medical advice if you think you have experienced one.

TIA: what is it?

A TIA occurs when blood flow to the brain is interrupted for just a short time. This brief ‘episode’ is sometimes referred to as a ‘mini-stroke’.

It occurs because one of the major arteries taking blood into the brain has become blocked, or partially blocked by a blood clot. This does not last long, which is why the condition is described as transient. It does mean, however, that the brain is still starved of oxygen for a short time. The medical term used to describe a lack of oxygen is ischaemia – so this is an ischaemic attack. Once the flow of blood is restored, because the clot dislodges, brain function usually returns to normal.

A TIA is different from an acute stroke. The latter is more serious as a blood vessel in the brain becomes blocked for a longer period. A full blown stroke often results in brain damage and needs intensive treatment and rehabilitation to recover. Most people who have a TIA often wrongly ignore it, putting it down to a dizzy spell or tiredness.

TIA: why does it happen?

A TIA can occur if a blood vessel in the brain becomes blocked by:

  • Atherosclerosis: a gradual build-up of fatty deposits and cholesterol in the blood vessels of the brain. The development of atherosclerosis is associated with high levels of low-density lipoprotein (LDL) cholesterol in the blood.
  • A blood clot that has travelled from another part of the body, such as the heart or carotid artery.
  • A bleed in the brain, although this is unusual.

TIA: the body raising the alarm

Older people in the Western world often experience TIAs and there are hundreds of thousands of cases every year. Most affect men rather than women, and age is a risk factor, so there are few cases in people younger than 35. TIA warns that someone is at risk of a future stroke but once someone has had a stroke, their risk of having a subsequent TIA is also increased.

The symptoms of a TIA are typically present for only a short time; lasting from just minutes to hours, and often disappear within 24 hours. Symptoms include:

  • A feeling of numbness or weakness in the face or limbs that affects one side of the body but that passes off quite quickly.
  • Having difficulty speaking or feeling confused, again just for a short time.
  • A very painful headache that suddenly appears and then gradually disappears.
  • Feeling dizzy or uncoordinated so much that you cannot walk.
  • Finding it hard to see out of one or both eyes.

A TIA should always be regarded as a warning. The underlying condition of the blood vessels that leads to the mini-stroke does not get better, even though there are no long-lasting effects. If the blood vessel blockage occurs again, it may not be transient the next time and can lead to a stroke.

Studies have found that about one in 20 people who have TIA symptoms go on to have a stroke in the next two days. Over one in 10 will have a stroke within seven days, and 15% of all diagnosed strokes occur after a TIA.