What You Need to Know About Strokes.

The painter was finishing the last of the living room ceiling when his vision suddenly blurred. He shook his head back and forth and rubbed his eyes, but still could not see clearly. He climbed slowly down the ladder and sat on the floor. He felt nauseous and felt a mild pain in the back of his head.

When his young assistant came in, the painter realized that he couldn't see his fellow worker's face when he looked directly at him. These symptoms lasted several minutes and then resolved. Later in the emergency ward he was told by the neurology resident on call that he had experienced a transient attack (or TIA) because of the lack of blood flow to the occipital region of the brain--the part that receives the visual input from the eyes. He had probably pinched off the arteries in the back of his neck while looking up to paint the ceiling. When he climbed down the ladder and put his head in a normal position, the artery pinching ceased and blood flow was restored.

The painter was lucky. The symptoms he experienced were warnings of a possible stroke and should not be ignored. These warnings can be caused by any interruption of blood flow to the brain, whether by a narrowing of an artery, an embolus (or clot breaking off from another location such as the heart or the arteries in the front of the neck), a decrease in the oxygen-carrying capacity of the blood, or a decrease in the output of blood from the heart.

Symptoms include: transient vision disturbance of one or both eyes, numbness or weakness of one side of the body; difficulty with swallowing, speaking, or understanding; imbalance; double vision; nausea; vomiting; headache; dizziness; or sudden loss of tone in the muscles of the extremities (drop attacks). Just because the symptoms disappear after several minutes does not mean that all is OK. Quite the contrary; it is imperative to report these warnings to a physician who can determine the exact cause and provide appropriate medical or surgical treatment. Otherwise the next time the symptoms appear, they may be more severe and may not resolve spontaneously.

When a patient arrives at the emergency ward or sees the neurologist, a careful history is taken, helping to localize the area of the brain or visual system involved. The brain is supplied by two arteries in the front (the carotids) and two in the back (the vertebrals). When the painter looked upward to view the ceiling he was painting, the arteries in the back were affected. These arteries travel to the base of the brain by passing through small holes, or foramina, in the spinal column of the neck and may be compressed if there is misalignment of one vertebral body on another. Other symptoms he may have had in addition to his visual difficulties in both eyes, nausea, and headache include double vision, difficulty swallowing or speaking, imbalance, weakness of one or both sides of the body, sensory disturbance in the face or extremities, sudden weakness in both legs (drop attack), or difficulty with coordination.

The symptoms caused by problems with the carotid circulation include temporary blindness or dimming vision of one eye, weakness or numbness of one side of the body, difficulty understanding or speaking, or loss of the ability to see out of one half the visual fields of both eyes. A patient looking directly at the examiner would not be able to see the right or left side of his face depending on which cerebral hemisphere were oxygen-starved. A favorite cause for an anterior circulation TIA is an embolus (blood clot) from the bifurcation (or splitting) of the common carotid artery in the neck into the internal and external carotid--the former carrying oxygenated blood to the brain and eye and the latter to the muscles and skin of the face and scalp. This inherently weak area breaks down in susceptible individuals and produces an ulcerated plaque that may form clots. Emboli (clots) can also come from the heart (which happens when patients develop atrial fibrillation--an erratic and inefficient beating of the atria or upper chambers of the heart) or from the aorta (the great vessel exiting the heart).

Certain conditions such as carbon monoxide poisoning from incompletely burned fuel can decrease the oxygen-carrying capacity of the blood and produce strokelike symptoms. Since carbon monoxide has an affinity for hemoglobin--the carrier of oxygen--that is more than 200 times that of oxygen, any carbon monoxide present in breathable air can become a problem. If you've been around a faulty fossil-fuel-burning stove (coal, oil, wood, natural gas) or a leaking exhaust pipe on an automobile, your physician should perform a test for carbon monoxide--a test that is not normally performed unless there is a high index of suspicion.

Migraine headaches can mimic vascular disease, since there is periodic spasm of small arteries of the eye and brain. The length of symptoms is similar--a duration of a few minutes to an hour--and generally there is a headache afterward. However, in a condition known as migraine equivalent there may be symptoms of brain ischemia without the headache. So this diagnosis must be made by excluding all other more serious causes of TIA.

The treatment of TIA depends on the accurate diagnosis of the cause. A physician may want to attempt converting a heart with atrial fibrillation to the normal regular sinus rhythm by medication or electrical cardioversion. If this is not possible, your doctor may elect to place you on Coumadin to thin the blood and hopefully prevent clot formation within the atria of the heart. This requires very careful follow-up to ascertain and maintain the correct dosage. Many medications may interfere with Coumadin and may prolong or shorten the clotting time of the blood. Therefore, the amount of Coumadin taken must be carefully monitored continually, depending on the blood studies. An ulcerated plaque of the carotid bifurcation may need to be surgically removed or, if deemed unsuitable for surgical removal, could also be treated with anticoagulant therapy such as antiplatelet drugs.

The underlying cause of each diagnosis is in large part genetically determined. However, remember that contributing factors such as obesity, high blood pressure, cigarette smoking, diabetes, and birth control pills may add to your risk. Those factors that we can change, such as cigarette smoking, hypertension and diabetes, alternate methods of birth control, lowering cholesterol, and indirectly increasing physical activity to lessen the chance of heart disease, may reduce the possibility of TIA and stroke. Certainly anyone who has a family history of heart disease or who has had any demonstrable vascular disease should not smoke, since this is the most important risk factor that can be eliminated.

The important thing to remember is to seek help immediately if you experience any of the warning symptoms described. TIA symptoms fading after several minutes does not mean that you are normal. Accurate diagnosis and appropriate treatment are essential to prevent permanent disability. Finally, everyone should take steps to minimize his or her risk factors for heart disease and stroke.

Symptoms of TIA or Stroke

* Numbness or weakness on
  one side of the body
* Transient loss of vision in
  one eye
* Difficulty swallowing
* Slurred speech
* Loss of left or right visual
  field
* Drop attacks
* Difficulty understanding or
  speaking
* Incoordination
* Headache
* Dizziness
* Double vision
* Nausea or vomiting

Stroke Risk Factors

* Family history of stroke
* Cigarette smoking
* High cholesterol
* Birth control pills
* High blood pressure
* Diabetes
* Obesity
* Heart disease
* History of TIA
* Atrial fibrillation
* Vascular disease

Randall Barre is a writer living in Chattanooga, Tennesse. He's a retired physician who specialized in neurology during his years of medical practice.