A transient ischemic attack (TIA), also known as a “mini stroke” has similar characteristics to a stroke, but unlike a stroke it only lasts up to 24 hours. The supply of oxygen enriched blood is cut off to part of the brain.
Although there is no permanent brain damage when a TIA occurs, sufferers are at high risk of having another one, as well as a full stroke.
A symptom is something the patient feels or reports, while a sign is something that other people, including the doctor or nurse detects. A headache may be an example of a symptom, while a rash may be an example of a sign.
Transient ischemic attacks typically last for only a few minutes and most of the symptoms are gone after an hour. It is possible to have a number of TIAs – each one may have similar or varying symptoms, such as:
- asbrupt paralysis, lack of sensation in the limbs or face, usually on just one side of the body.
- sudden loss of sight in one or both eyes
- problems understanding speech and/or difficulty speaking
- trouble swallowing
- lack of coordination and balance
- feeling dizzy
If there is long-term damage to the brain or the symptoms last for more than 24 hours, then it is classed as a stroke. If you suspect someone is having a transient ischemic attack, there are a number of signs to look out for. The individual’s face may have dropped to one side, there may be drooping of an eye or the mouth. In some cases the person cannot keep their arms up in the air. Speech may be slurred.
The main cause of a transient ischemic attack is the same as that of an ischemic stroke (regular type of stroke). They occur when oxygen rich blood supply is temporarily cut off. This is due to one of the small blood vessels supplying oxygen becoming blocked. Possible causes of this blockage are:
- A blood clot – may happen as a result of a blood condition (e.g. sickle cell anemia) or a heart condition (e.g. atrial fibrillation). There may be other reasons.
- An embolism – is a blood clot that formed somewhere else within the body and travels through the bloodstream to a blood vessel that supplies the brain with oxygen
- Atherosclerosis – is a condition where fatty deposits build up in the blood vessels, resulting in tightening of the arteries
When this happens during an ischemic stroke, the oxygen supply is cut off long enough to cause potential brain damage, as the brain cells will start to die. With a transient ischemic attack the oxygen supply returns quickly enough for there to be no damage to the brain. There are some rare cases where a transient ischemic attack has been caused by a hemorrhage.
There are certain risk factors that are out of the person’s control, these are known as “fixed risk factors” and they include:
- Family History – Individuals who have a close relative who had a TIA are at higher risk of developing one themselves.
- Gender – Men have an increased risk of experiencing a transient ischemic attack. However, the risk is similar among older males and females (post-menopausal).
- Age – As a person ages, their risk of suffering a TIA increases. This is due to their arteries decreasing in elasticity and width as they age.
- Ethnicity – Certain races (African, South Asian and Caribbean) are more prone to diabetes and high blood pressure – both risk factors for mini stroke.
The following are lifestyle risk factors that are linked to a higher risk of TIA:
- Being overweight
- Being physically inactive
- Having a poor diet with high fat, salt content and low in nutrients
- Drinking heavily
Also there are a number of medical conditions that can increase the chances of having a TIA, these include:
TIAs do not last long enough for a doctor to be there to make a diagnosis. If you are aware of some symptoms, remember to describe them carefully to your doctor.
The doctor will check through the risk factors linked to stroke and TIA risk. In some cases a neurological exam may be ordered.
If a GP (general practitioner, primary care physician) detects some TIA signs, the patient may be referred to a specialist, who may be a neurologist, stroke specialist, or geriatrician. If a TIA clinic is available nearby, the patient may be sent there. For TIA symptoms referral must occur within a week. If this is a second attack, the patient needs to see the specialist immediately.
In order to help reach an accurate diagnosis, the doctor may order the following tests:
- Blood tests – to check blood sugar levels, cholesterol levels and clotting ability.
- Chest X-ray – to look for signs of any underlying medical conditions
- CT (Computerized Tomography) scan – a series of X-rays produces a 3-D image of the entire inside of your body, which in this case is done on the brain. Tumors and hemorrhages will show up on the scan, both are known causes of TIAs.
- CTA (Computerized Tomography Angiography) scan – the same as CT scans but performed to help check the condition of the arteries in the brain and neck. A contrast material may be injected into a blood vessel as this will show up on the scan making it easier to assess.
- Echocardiogram – this procedure uses sound waves to produce an ultrasound image of the heart and can aid in diagnosis of any heart conditions.
- ECG (Electrocardiogram) – this is a test that can spot any abnormal rhythms of the heart. It uses adhesive electrodes to gauge the heart’s electrical activity.
- MRI (Magnetic Resonance Imaging) scan – this process uses radio waves and a strong magnetic field to produce an image of greater detail to that produced by a CT scan.
- Ultrasound scan – again this is a process that produces an image of the inside of the body, this time using high frequency sound waves. This is the most common method for identifying the source of atherosclerosis.
Treatment decisions will depend on many factors, such as the patient’s age, medical history and the characteristics of some of the signs and symptoms. Proper and effective treatment will greatly reduce the chances of having another TIA or a subsequent stroke.
The doctor may recommend:
- Surgery – especially when the carotid artery (artery in your neck) has become narrow due to fatty deposits building up inside (atherosclerosis). In this case the type of surgery performed is known as carotid endarterectomy, it involves clearance of fatty deposits and removal of a portion of the damaged artery. If the blockage in the artery is too large or too small the procedure might not be advised, as the risks could outweigh the benefits.
- Angioplasty – can be used to open a blocked artery. During an angioplasty, a balloon like device is inserted into the blocked part of the artery and inflated, this opens up the artery. Afterwards a small wire tube is inserted into the artery, this keeps the artery open.
- Medication – These may include anti-platelet drugs (e.g. asprin or clopidogrel) to reduce blood clotting, drugs to treat hypertension, anticoagulants, and cholesterol medication.
All patients should have a computed tomography scan within 24 hours of experiencing mild stroke, or a transient ischemic attack, as it could predict their risk of another stroke. This is according to a new study published in Strok – a journal of the American Heart Association.
- Maintain a healthy body weight
- Have a healthy balanced diet, including plenty of fruit and vegetables, and avoid too much fat and cholesterol
- Don’t smoke
- Avoid heavy drinking
- Control your diabetes
- Exercise regularly
- Avoid illegal drugs such as cocaine
Written by Mike Paddock