A "mini-stroke" or "transient ischemic attack" (TIA) occurs when there is a temporary drop in the blood supply to the brain, depriving it of essential oxygen. The patient experiences stroke-like symptoms, although they don't last as long. A mini-stroke only lasts a few minutes and disappears within a day.
In other words, a TIA is like a stroke, produces similar symptoms, but only lasts a few minutes and causes no permanent damage.
It is estimated that up to 500,000 people in the US experience a TIA each year.
Although symptoms fade away rapidly, most patients do not seek medical help. Between 10% and 15% of TIA patients have a full-blown stroke within three months - 40% of those strokes occur within 24 hours.
Rapid evaluation and treatment of patients who experienced a mini-stroke, either in specially designed TIA clinics or the emergency room, can significantly reduce the risk of subsequent stroke.
Contents of this article:
Fast facts on transient ischemic attack (TIA)
Here are some key points about transient ischemic attack (TIA). More detail and supporting information is in the main article.
- A mini-stroke occurs when blood is temporarily cut off to regions of the brain
- Around 500,000 Americans have a stroke each year
- Rapid care is essential to minimize the medical implications of a stroke
- Symptoms of a stroke include weakness in the limbs and slurred speech
- Causes of TIAs include atherosclerosis and blood clots
- Risk factors include smoking, family history, diabetes and a bad diet
- Diagnosis of TIA may include an electrocardiogram, X-ray and ultrasound
- The object of TIA treatment is to prevent further occurrences
- One of the most common drugs used to prevent TIAs is warfarin, an anticoagulant medication.
Symptoms of a TIA (mini-stroke)
The acronym FAST represents the signs and symptoms of stroke.
A symptom is something the patient experiences or reports, such as a headache, while a sign is something others detect, such as a rash. The signs and symptoms of a TIA are represented by the abbreviation FAST (Face, Arms, Speech, Time):
- Face - the face may fall on one side as some of the facial muscles become paralyzed. The patient's eye or mouth may droop, and he/she may be unable to smile properly.
- Arms - arm weakness or numbness might make it hard for the patient to either raise both arms, or to keep them raised.
- Speech - speech may be slurred and garbled.
- Time - when you see at least one of these symptoms it is Time to dial emergency services (911 in USA, 999 in UK).
If signs and symptoms last more than 24 hours or cause lasting brain damage, it's considered a stroke. Do not wait 24 hours to find out!
Being able to identify the signs and symptoms present in FAST is especially important if you live with somebody in a high risk group, such as an elderly person, or an individual with hypertension (high blood pressure) or diabetes.
Other signs and symptoms of a TIA include:
- Difficulty talking
- Difficulty understand what others are talking about
- Swallowing difficulties
- Very bad headache
- Paralysis, numbness or weakness on one side of the body
- In severe cases, loss of consciousness.
If you or somebody else has at least three of these signs and symptoms medical attention should be sought immediately.
TIA symptoms are temporary and should disappear within 24 hours. They may last from a couple of minutes to 15 minutes. TIA sufferers experience varying symptoms, depending on which part of the brain is affected.
In some cases a TIA may be a prelude to a full stroke, in which case permanent and possibly serious damage occurs. Prompt medical attention and treatment significantly reduces the risk of experiencing another TIA or stroke.
In other words - if think that you, or somebody else, is having a TIA, get medical attention immediately.
Causes of a TIA
- Disruption of blood supply to the brain
Two main blood vessels - the carotid arteries - supply blood to the brain. These arteries branch off into many smaller blood vessels which provide the whole of the brain with essential nutrients, such as blood, glucose, and oxygen. A TIA can occur if one of the smaller blood vessels becomes blocked, depriving that part of the brain of oxygen-rich blood.
In the case of a TIA, the blocked blood supply is temporary and the affected part of the brain soon returns to normal. When a full stroke occurs the oxygen-rich blood supply is disrupted for much longer, causing brain cells to die.
Blood supply to parts of the brain is usually disrupted because of a narrowing of the arteries (stenosis) or the formation of a blood clot.
- Atherosclerosis - atherosclerosis causes arteries to narrow (stenosis). Fatty deposits (plaque) develop on the inner lining of blood cells, causing them to become hardened, thickened and less flexible - resulting in more difficulties with blood flow.
- Blood clots - a blood clot can disrupt the supply of oxygen-rich blood to parts of the brain. Blood clots are usually caused by:
- Heart conditions - congestive heart muscle disease or atrial fibrillation are common causes of blood clots
- Blood conditions - leukemia (blood cell cancer), sickle cell anemia, hyperlipidemia (high blood fat levels), polycythemia (very thick blood), or thrombocyemia (overproduction of blood platelets) are common causes of blood clots
- Infections - phlebitis can cause blood clots.
- Hemorrhage (internal bleeding) - a minor brain hemorrhage (small amount of bleeding in the brain) can cause a TIA; however, this is rare.
Risk factors for TIA
Risk factors for TIA include ethnic origin, age and family history.
There are some risk factors we can change, and others we cannot
Risk factors we cannot change:
- A family history - people with a family history of TIA or stroke, i.e. people with a close relative who has had a stroke or TIA, have a higher risk of experiencing one themselves
- Age - people aged 55 years or more have a higher risk of TIAs compared to younger people. The older you get, the higher the risk becomes
- Sex - males have a slightly higher risk of stroke and/or TIA than women
- Ethnic origin - people of black African ancestry have a higher risk of stroke and TIA than others
Risk factors we can change:
- Hypertension - people with high blood pressure have a significantly higher risk of developing a TIA, compared to people of normal blood pressure. Hypertension means the patient's systolic blood pressure is 140 mm hg or higher, and diastolic pressure is 90 mm hg or higher.
- Cardiovascular disease - people with cardiovascular diseases have a higher risk of stroke and/or TIA. This includes a heart defect, heart failure or arrhythmia (abnormal heart rhythm).
- Carotid artery disease - this is when the blood vessels in the neck that lead to the brain are clogged.
- PAD (peripheral artery disease) - people whose blood vessels that carry blood to their arms and legs become clogged have a higher risk of stroke and TIA.
- Smoking - smoking increases the risk of various diseases and conditions, including TIA, stroke, blood clots, heart attack, cardiovascular disease, cancer, erectile dysfunction, and blindness in old age.
- Sedentary lifestyle - people who are physically inactive have a significantly higher risk of stroke or TIA compared to people who do 30 minutes of moderate exercise at least 5 times per week.
- Diabetes - patients with diabetes are more likely to suffer from atherosclerosis (narrowing of the arteries due to a build up of fatty deposits), raising the risk of stroke or TIA. This is especially the case if the diabetes is poorly controlled.
- Bad diet - people who consume too much bad quality fat and/or salt have a higher risk of stroke and TIA.
- Blood cholesterol levels - if your blood cholesterol level is at least 200 mg/dL or 5.2 mmol/L you have a higher risk of TIA or stroke.
- Homocysteine levels - homocysteine is an amino acid produced by the body. It is usually a byproduct of consuming meat. It is made from another amino acid, methionine, and then is concerted into other amino acids. Elevated levels of homocysteine in the blood can make the arteries thicken and scar, and more susceptible to clogs, resulting in a higher risk of stroke and TIA.
- Bodyweight - obese people have a significantly higher risk of stroke or TIA than people of normal body weight.
- Alcohol - people who drink large quantities of alcohol regularly are much more likely to have a stroke or TIA than people who never drink or drink within recommended limits.
- Illegal drugs - some illegal drugs, such as cocaine, can raise the risk of stroke or TIA if taken often enough.
On the next page, we look at diagnosis, treatment and prevention of TIAs.