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Transient ischemic attack
 
 
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A transient ischemic attack (TIA, often colloquially referred to as “mini stroke”) is caused by the changes in the blood supply to a particular area of the brain
Brain

The brain is the center of the nervous system in all vertebrate, and most invertebrate, animals. Some primitive animals such as cnidarian and echinoderm have a decentralized nervous system without a brain, while sponges lack any nervous system at all....
, resulting in brief neurologic dysfunction that persists, by definition, for less than 24 hours; if symptoms persist then it is categorized as a stroke
Stroke

A stroke is the rapidly developing loss of brain function due to a disturbance in the blood supply to the brain. According to the National Stroke Association, a "stroke" occurs when a blood clot blocks and artery or a blood vessel breaks, interrupting blood flow to an area of the brain....
.

A cerebral infarct that lasts longer than 24 hours, but less than 72 hours is termed a reversible ischemic neurologic deficit or RIND.

toms vary widely from person to person, depending on the area of the brain involved.






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A transient ischemic attack (TIA, often colloquially referred to as “mini stroke”) is caused by the changes in the blood supply to a particular area of the brain
Brain

The brain is the center of the nervous system in all vertebrate, and most invertebrate, animals. Some primitive animals such as cnidarian and echinoderm have a decentralized nervous system without a brain, while sponges lack any nervous system at all....
, resulting in brief neurologic dysfunction that persists, by definition, for less than 24 hours; if symptoms persist then it is categorized as a stroke
Stroke

A stroke is the rapidly developing loss of brain function due to a disturbance in the blood supply to the brain. According to the National Stroke Association, a "stroke" occurs when a blood clot blocks and artery or a blood vessel breaks, interrupting blood flow to an area of the brain....
.

A cerebral infarct that lasts longer than 24 hours, but less than 72 hours is termed a reversible ischemic neurologic deficit or RIND.

Symptoms

Symptoms vary widely from person to person, depending on the area of the brain involved. The most frequent symptoms include temporary loss of vision (typically amaurosis fugax
Amaurosis fugax

Amaurosis fugax is a transient monocular visual loss....
); difficulty speaking (aphasia
Aphasia

Aphasia , also known as rhymnasia, is a loss of the ability to produce and/or comprehend language, due to injury to brain areas specialized for these functions, such as Broca's area, which governs language production, or Wernicke's area, which governs the interpretation of language....
); weakness on one side of the body (hemiparesis
Hemiparesis

Hemiparesis is weakness on one side of the body. Contrast with Hemiplegia, which is total paralysis of the arm, leg, and trunk on the same side of the body....
); and numbness or tingling (paresthesia
Paresthesia

Paresthesia is a sensation of tingling, pricking, or numbness of a person's skin with no apparent long-term physical effect. It is more generally known as the feeling of "pins and needles" or of a human limb being "asleep" ....
), usually on one side of the body. Impairment of consciousness is very uncommon. There have been cases where there have been a temporary paralysis of a part of the face and the tongue.

Effects of a TIA


Prognosis

Patients diagnosed with a TIA are sometimes said to have had a warning for an approaching stroke
Stroke

A stroke is the rapidly developing loss of brain function due to a disturbance in the blood supply to the brain. According to the National Stroke Association, a "stroke" occurs when a blood clot blocks and artery or a blood vessel breaks, interrupting blood flow to an area of the brain....
. If the time period of blood supply impairment lasts more than a few minutes, the nerve cells of that area of the brain die and cause permanent neurologic deficit. One third of the people with TIA later have recurrent TIAs and one third have a stroke due to permanent nerve cell loss.

The ABCD2 score can predict likelihood of subsequent stroke, and is calculated as:
  • Age at or above 60 years = 1 point
  • Blood pressure at presentation at or above 140/90 mm Hg = 1 point
  • Clinical features
    unilateral weakness = 2 points
    speech disturbance without weakness = 1 point
  • Duration of attack
    at or above 60 minutes = 2 points
    10 to 59 minutes = 1 point
  • Diabetes = 1 point


Interpretation of score, the risk for stroke:
  • Score 1-3 (low)
    • 2 day risk = 1.0%
    • 7 day risk = 1.2%
  • Score 4-5 (moderate)
    • 2 day risk = 4.1%
    • 7 day risk = 5.9%
  • Score 6–7 (high)
    • 2 day risk = 8.1%
    • 7 day risk = 11.7%


Causes

The most common cause of a TIA is an embolus
Embolism

In medicine, an embolism occurs when an object migrates from one part of the body and causes a blockage of a blood vessel in another part of the body....
 that occludes an artery in the brain. This most frequently arises from a dislodged atherosclerotic plaque
Atheroma

In pathology, an atheroma is an accumulation and swelling in artery walls that is made up of cells , or cell debris, that contain lipids , calcium and a variable amount of fibrous connective tissue....
 in one of the carotid arteries (i.e. a number of major arteries in the head and neck) or from a thrombus
Thrombus

A thrombus , or blood clot, is the final product of the blood coagulation step in hemostasis. It is achieved via the aggregation of platelets that form a platelet plug, and the activation of the humoral coagulation system ....
 (i.e. a blood clot) in the heart due to atrial fibrillation
Atrial fibrillation

Atrial fibrillation is a cardiac arrhythmia that involves the two upper chambers of the heart. It can often be identified by taking a pulse and observing that the heartbeats don't occur at regular intervals, but a conclusive indication of AF is the absence of P waves on an electrocardiogram ....
.

Other reasons include excessive narrowing of large vessels due to an atherosclerotic plaque and increased blood viscosity due to some blood diseases. TIA is related with other medical conditions like hypertension
Hypertension

Hypertension, also referred to as high blood pressure, HTN or HPN, is a medical condition in which the blood pressure is chronically elevated....
, heart disease
Heart disease

Heart disease is an umbrella term for a variety for different diseases affecting the heart. As of 2007, it is the leading cause of death in the United States, England, Canada and Wales, killing one person every 34 seconds in the United States alone....
 (especially atrial fibrillation
Atrial fibrillation

Atrial fibrillation is a cardiac arrhythmia that involves the two upper chambers of the heart. It can often be identified by taking a pulse and observing that the heartbeats don't occur at regular intervals, but a conclusive indication of AF is the absence of P waves on an electrocardiogram ....
), migraine
Migraine

Migraine is a neurology syndrome characterized by altered bodily perceptions, headaches, and nausea. Physiologically, the migraine headache is a neurological condition more common to women than to men....
, cigarette smoking, hypercholesterolemia
Hypercholesterolemia

Hypercholesterolemia is the presence of high levels of cholesterol in the blood . It is not a disease but a metabolism derangement that can be secondary to many diseases and can contribute to many forms of disease, most notably cardiovascular disease....
, and diabetes mellitus
Diabetes mellitus

Diabetes mellitus , often referred to simply as diabetes , is a syndrome of disordered metabolism, usually due to a combination of genetic disorder and environmental causes, resulting in abnormally high blood sugar levels ....
.

Differential

If visual symptoms occur such as perception of wavy or jagged lines or tiny specks of light and if a headache occurs, this can be an atypical migraine
Migraine

Migraine is a neurology syndrome characterized by altered bodily perceptions, headaches, and nausea. Physiologically, the migraine headache is a neurological condition more common to women than to men....
 presentation. Typically a history of prior migraines is present. Also, a partial seizure in the parietal area of the brain can mimic TIA symptoms.

Prevention


Medication

The use of anti-coagulant medications, heparin
Heparin

Heparin, a highly-sulfated glycosaminoglycan, is widely used as an injectable anticoagulant and has the highest negative charge density of any known biomolecule....
 and warfarin
Warfarin

Warfarin is an anticoagulant. It was initially marketed as a pesticide against rats and mice, and is still popular for this purpose, although more potent poisons such as brodifacoum have since been developed....
; or anti-platelet
Platelet

Platelets, or Thrombocyte, are small, irregularly shaped anuclear cells, 2-4?m in diameter, which are derived from fragmentation of precursor megakaryocytes....
 medications such as aspirin
Aspirin

Aspirin , also known as acetylsalicylic acid , is a salicylate medication, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication....
.

Treatment

The mainstay of treatment following acute recovery from a TIA should be to diagnose and treat the underlying cause. It is not always immediately possible to tell the difference between a CVA (stroke) and a TIA. Most patients who are diagnosed at a hospital's emergency department
Emergency department

The emergency department , sometimes termed the emergency room , emergency ward , accident & emergency department or casualty department is a hospital or primary care department that provides initial treatment to patients with a broad spectrum of illnesses and injury, some of which may be Medical emergency and requiri...
 as having suffered from a TIA will be discharged home and advised to contact their primary physician to organize further investigations. TIA can be considered as the last warning. The reason for the condition should be immediately examined by imaging of the brain.

The initial treatment is aspirin
Aspirin

Aspirin , also known as acetylsalicylic acid , is a salicylate medication, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication....
, second line is clopidogrel
Clopidogrel

Clopidogrel is an oral Antiplatelet drug to inhibit blood clots in coronary artery disease, peripheral vascular disease, and cerebrovascular disease....
, third line is ticlopidine
Ticlopidine

Ticlopidine is an antiplatelet drug in the thienopyridine family. Like clopidogrel, it is an adenosine diphosphate receptor inhibitor. It is used in patients in whom aspirin is not tolerated, or in whom dual antiplatelet therapy is desirable....
. If TIA is recurrent after aspirin treatment, the combination of aspirin
Aspirin

Aspirin , also known as acetylsalicylic acid , is a salicylate medication, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication....
 and dipirydamole is needed (Aggrenox).

An electrocardiogram
Electrocardiogram

An electrocardiogram is a recording of the electricity activity of the heart over time produced by an electrocardiograph, usually in a Non-invasive recording via skin electrodes....
 (ECG) may show atrial fibrillation, a common cause of TIAs, or other arrhythmias that may cause embolisation to the brain. An echocardiogram is useful in detecting thrombus within the heart chambers. Such patients benefit from anticoagulation.

If the TIA affects an area supplied by the carotid artery, an ultrasound
Ultrasound

Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing . Although this limit varies from person to person, it is approximately 20 Hertz in healthy, young adults and thus, 20 kHz serves as a useful lower limit in describing ultrasound....
 (TCD
Transcranial doppler

Transcranial Doppler is a test that measures the velocity of blood flow through the brain's blood vessels. Used to help in the diagnosis of emboli, stenosis, vasospasm from a subarachnoid hemorrhage , and other problems, this relatively quick and inexpensive test is growing in popularity in the United States....
) scan may demonstrate carotid stenosis
Stenosis

A stenosis is an abnormal narrowing in a blood vessel or other tubular Organ or structure.It is also sometimes called a "stricture" .The term "coarctation" is synonymous, but is commonly used only in the context of aortic coarctation....
. For people with a greater than 70% stenosis within the carotid artery, removal of atherosclerotic plaque by surgery, specifically a carotid endarterectomy
Carotid endarterectomy

Carotid endarterectomy is a surgery procedure used to prevent stroke, by correcting carotid stenosis in the carotid artery. Endarterectomy is the removal of material on the inside of an artery....
, may be recommended.

Some patients may also be given modified release dipyridamole or clopidogrel.

To reduce recurrence of an attack ACE Inhibitors are used. The aim is not to lower blood pressure in a hurry as too low too fast may increase ischaemic injury due to low perfusion pressure.

External links

  • at discovery.com
  • at MedlinePlus