Transient ischaemic attack (TIA)
What is a transient ischaemic attack?
A transient ischemic attack (TIA) is a temporary neurological episode. It is also known as a 'mini-stroke'. It is caused by a temporary blockage or narrowing in a blood vessel leading to the brain. A person experiencing TIA will have signs and symptoms like those of a stroke, but will recover completely within minutes or a few hours.
TIA's main significance is as a warning sign: TIAs occur when the blood vessels feeding the brain are not in good condition. A person who has had a TIA is at serious risk of stroke, often within days of the TIA.
Signs and symptoms
The signs and symptoms of a TIA are like those of a stroke. The difference between TIA and stroke is that in a TIA signs and symptoms are completely resolved, usually within a few minutes, while a stroke's effects are permanent. Thus, it is impossible - and inadvisable - to try and tell a TIA from a stroke while it is occurring.
Early warning signs - FAST
The FAST test is a set of early warning signs for stroke that anyone can use to recognize stroke. FAST is an acronym used to remember these points:
- Face - is the person's face droopy, flaccid, especially just on one side? Can they smile?
- Arms - can the person lift both their arms above their head?
- Speech - is the person having problems speaking and/or understanding speech? Is speech slurred?
- Time - the quicker you act, the better the chance of survival and recovery. Call 911, even if the symptoms go away.
Additional TIA signs and symptoms
Symptoms of a TIA include:
- Sudden paralysis of one side of the body (hemiplegia);
- Sudden weakness on one side of the body (hemiparesis), inability to move or lift the arm;
- Movement and coordination problems, especially if on one side only;
- Confusion, difficulty with speech or understanding speech, formulating thoughts, memory loss;
- Sudden, severe headache;
- Dizziness, vertigo;
- Nausea, vomiting, and;
- Blurred vision, loss of vision, or seeing only half the regular vision field (hemianopia), or a sudden blindness in one eye (amaurosis fugax). 
TIA and migraine
The early signs of a stroke can sometimes be similar to those of migraine. An authoritative diagnosis can only be made with a brain scan. For people who suffer from migraines, it is important to notice irregularities in their migraine symptoms and be alert to the possibility of stroke. An attack that is much more sudden than usual, and/or has different visual symptoms, might not be a migraine attack, but an early sign of stroke.
Causes and types
A TIA is caused by a temporary blockage or narrowing in a blood vessel leading to the brain. Loss of blood supply to an area of the brain will cause a temporary problem within that area. In a TIA, the blood clot normally dissolves after a few minutes, and normal blood flow to the brain area is resumed.
A TIA can be the result of:
- A blood clot that forms in one of the brain's arteries;
- A blood clot that arrives at the artery from elsewhere in the body;
- A narrowing in a brain artery that reduces the blood flow within it, or;
- Minor damage to an artery that causes some bleeding before the blood vessel self-repairs.
Risk factors for TIA are similar to those of stroke, and include:
- High blood pressure;
- Age - anyone can have a TIA, but the risk increases in older adults;
- A poor diet, obesity, high cholesterol;
- A sedentary lifestyle;
- Stress and depression;
- A family history of stroke;
- Ethnicity - the chance of stroke is higher in some populations;
- Excessive alcohol consumption;
- Heart disease, such as atrial fibrillation, and;
- A recent TIA or a previous stroke.
Methods for diagnosis
Since a TIA is sudden and is over quickly, diagnosis of a TIA typically happens after it has passed. Your doctor will ask you about your medical history and status, and about the symptoms you have experienced. Your doctor may then have you undergo a brain scan (a CT scan or an MRI) to understand why the TIA occurred and check for the risk of a future stroke. Blood tests can also help with diagnosis.
Your heart activity may also be examined and monitored, as stroke events can be closely related to heartbeat abnormalities.
Types of treatment
TIA in itself is not treated, as it is a temporary event and leaves no lasting damage. After a TIA, the focus will be on monitoring you for signs of a stroke and preventing a stroke from occurring. This may include medication (for example, drugs to lower blood pressure) and lifestyle change (such as quitting smoking). Surgery is also an option in some cases.
The specific treatment after a TIA depends on underlying risk factors.
A TIA in itself is thought to leave no lasting damage, and its main significance is as a warning sign. However, some recent research suggests that TIAs can cause minor brain injury.  These may not affect the person in a noticeable way, but if TIAs recur, they may have a cumulative effect on brain health.
You can lower your chances of a TIA (or the chances of further TIAs and a stroke) by adopting a healthier lifestyle; by limiting your alcohol consumption, quitting smoking, exercising and eating healthier food.