Transient ischemic attack

A transient ischemic attack (TIA, often colloquially referred to as "mini stroke") is caused by the temporary disturbance of blood supply to a restricted area of the brain, resulting in brief neurologic dysfunction that usually persists for less than 24 hours.

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), difficulty speaking (dysphasia), weakness on one side of the body (hemiparesis), numbness usually on one side of the body, and loss of consciousness. If there are neurological symptoms persisting for more than 24 hours, it is classified as a cerebrovascular accident (stroke).

Prognosis

Patients diagnosed with a TIA are sometimes said to have had a warning for an approaching cerebrovascular accident. 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.

Causes

The most common cause of a TIA is an embolus (a small blood clot) that occludes an artery in the brain. This most frequently arises from an atherosclerotic plaque in one of the carotid arteries or from a thrombus in the heart due to atrial fibrillation.

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, heart disease (especially atrial fibrillation), migraine, cigarette smoking, hypercholesterolemia, and diabetes mellitus.

Treatment

The mainstay of treatment following acute recovery from a TIA should be to diagnose and treat the underlying cause. Most patients who are diagnosed at a hospital's Accident & Emergency Department as having suffered from a TIA will be discharged home and advised to contact their primary physician to organize further investigations.

An electrocardiogram (EKG) 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 scan may demonstrate carotid stenosis. For people with a greater than 70% stenosis within the carotid artery, removal of atherosclerotic plaque by surgery, specifically a carotid endarterectomy, may be recommended.

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

First Aid

CALL 911 IMMEDIATELY.

This is a life threatening emergency.

You can not tell the difference between a CVA (stroke) and a TIA in the field.

Ensure the patient's airway remains open.

A person having a stroke may suddenly lose consciousness. Get the patient to sit down.

Watch for any changes in the patient's speech or level of consciousness. If the patient loses consciousness, monitor respirations and pulse and be ready to perform CPR. Look for muscle droop on one side of the patient's face, or weakness on one side of the patient's body. Note if the pupil in one eye is larger than the other. If possible, record the patient's pulse and respiratory rate every five minutes and provide this information to the EMS or the treating physician.

There is almost nothing that can be done in the field for a patient suffering a stroke or a TIA.

If you have oxygen, administer it at low concentration, high concentration if the patient has difficulty breathing.

DON'T GIVE ASPIRIN.

If it is a stroke, it might be caused by a blood clot (embolism) or a ruptured blood vessel (hemorrhage.) Aspirin is a blood thinner. If given to a person who is bleeding, it will make it worse.

Incidentally, there is not much an EMS crew can do for a patient who is suffering from a stroke. If the ambulance is delayed, the best thing you can do is put the patient in your car and go to the nearest hospital without any delay. Seconds count.

External link

TIAs at discovery.com

Cardiovascular diseases | Neurology