A TIA has symptoms similar to a stroke (apoplexy), but the symptoms disappear completely within a certain period of time. The cause is - as in a stroke - usually a blood clot that clogs a small vessel in the brain. Like a stroke, a TIA is an emergency: if you notice any symptoms, you should alert the emergency services immediately, even if the symptoms have already subsided. In addition, a TIA is an important warning sign, because the risk for a stroke is significantly increased after a TIA.
Definition of a TIA
TIA stands for Transient Ischemic Attack. By this, physicians understand a temporary lack of blood flow (ischemia) of areas of the brain, which manifests itself by the symptoms of a stroke. The earlier definition was TIA if the symptoms did not last longer than 24 hours.
Currently, a new definition is discussed, according to which the time window for symptom regression in a TIA is only one hour. In addition, MRI of the skull is needed for diagnosis: by definition, TIA does not show signs of circulatory damage to areas of the brain, unlike a stroke on MRI.
Stroke for symptom duration over 24 hours
An attack in which symptoms persist between 24 hours and seven days was previously called prolonged reversible ischemic neurological deficit (PRIND) or minor stroke. However, these terms for an "intermediate" of stroke and TIA are less common today, as it is assumed that these cases are already "true" strokes.
TIA symptoms: as in a stroke
The symptoms of a TIA are basically indistinguishable from the signs of a stroke - but they may be less pronounced. A particularly common symptom of TIA is a few seconds to minutes of blindness or severe eye deterioration (Amaurosis fugax).
In addition, a TIA can express itself by the following, usually sudden symptoms:
- Paralysis: It can affect one half of the body, one half of the face, or only one extremity - typically a drooping corner of the mouth or difficulty walking
- Motor disturbances such as difficulty in performing simple manipulations
- Feelings such as numbness, tingling or a "furry" feeling
- blurred vision
- Speech disorders such as slurred speech, difficulty in formulating complete sentences or word-finding disorders
- Disorders of speech understanding
- Dizziness or balance disorders
- Awareness disorder, confusion or personality change
Blood clots and migraines as possible causes
In a TIA, certain areas of the brain are temporarily under-supplied with oxygen due to a circulatory disorder. The cause is often a blood clot that clogs a small vessel.
Often the clot comes from a plaque that has formed as part of arteriosclerosis (arteriosclerosis) in the carotid artery. Rarely, in heart disease such as atrial fibrillation, a blood clot can also be carried from the heart into a cerebral vessel (cardiac embolism).
A TIA can also arise in the context of a migraine: It causes a spasmodic constriction of a blood vessel (vascular spasm) a circulatory disorder in the brain.
MRI for diagnostics
In a TIA, it is important that you tell the doctor the symptoms as accurately as possible, even if they were of a short duration. In addition, you should name him possible pre-existing conditions - for example, a coronary heart disease or atrial fibrillation.
Usually, an MRI of the skull is performed: it provides information about the extent, location and extent of deficient blood flow. Circulatory damage to the brain tissue can also be detected - in this case, according to the definition, there is no TIA but a stroke.
Under certain circumstances further investigations may be necessary in the diagnosis:
- CT of the skull to prevent bleeding
- Ultrasound of the vessels (duplex or Doppler sonography)
- Representation of the cerebral vessels in an x-ray examination with contrast agent (digital subtraction angiography)
- Long-term ECG and cardiac ultrasound to detect potential heart disease as a source of blood clots
- 24-hour blood pressure measurement
- Determination of blood lipid levels
Treatment by anticoagulation
Patients with TIA should, if possible, be monitored for at least 24 hours on a so-called stroke unit - a special ward for stroke patients. Usually, a therapy with anti-coagulant drugs is started to prevent the formation of further blood clots.
Mostly, the active substance acetylsalicylic acid (ASA) is given as an infusion, alternatively, clopidogrel can also be used. As a rule, treatment with aspirin or clopidogrel in tablet form must be continued on a permanent basis. In the case of atrial fibrillation, therapy with a coagulation inhibitor such as Marcumar® may additionally or alternatively be necessary.
Increased stroke risk
After a TIA, the risk of a stroke is significantly higher: Up to 40 percent of patients experience a stroke within five years, about 10 to 15 percent already within the first two weeks.
By appropriate therapy and further preventive measures, however, the risk can be significantly reduced. Therefore, it is important that the necessary diagnostics and treatment are initiated as soon as possible in a TIA.
ABCD2 score for risk assessment
The so-called ABCD2 score can be used to estimate the risk of stroke. Points are awarded for the following risk factors:
- Age of the patient over 60 years
- Blood pressure higher than 140/90 mmHg
- Special symptoms (English: clinic): Semi-sided paralysis or speech disorders
- Duration of symptoms
- Diabetes mellitus as a previous disease
Depending on the score, the risk of having a stroke within two days of a TIA is estimated at up to eight percent.
Prevention: minimize risk factors
In addition to therapy with anticoagulant drugs, further risk factors must be minimized after a TIA in order to prevent a stroke. These include, for example, the treatment of high blood pressure (arterial hypertension) and the optimal adjustment of blood glucose levels in diabetes mellitus.
In addition, the LDL cholesterol should be reduced below 100 mg / dl, which usually a blood lipid lowering drug (statin) is prescribed. Arteriosclerosis with severe narrowing of the carotid artery may require surgery to remove the plaque to prevent the formation of new blood clots.
Change Lifestyles - Prevent Stroke
Having a healthy lifestyle can do a great deal for you to reduce your risk of stroke:
- Stop smoking: Nicotine consumption promotes the development of arteriosclerosis.
- Pay attention to regular exercise: Sport has a positive effect on blood pressure and blood lipids.
- Reduce your alcohol intake: Alcohol can increase the risk of stroke.
- Strive for a normal weight: Obesity promotes the development of risk factors for cardiovascular disease.