Sunday, January 20, 2008


AVMs can cause a wide range of specific neurological symptoms that vary from person to person, depending upon the location of the malformation. These symptoms may include muscle weakness or paralysis, loss of coordination, difficulty carrying out tasks that require planning, dizziness, visual disturbances, problems using or understanding language, abnormal sensations (such as numbness, tingling, or spontaneous pain), memory deficits, mental confusion, hallucinations, or dementia.

It was noted that during his phone call with reporters the Senator began having difficulty with his speech, including having problems finding the words he wanted to say and slurring his speech. Senator Johnson was displaying the signs that he was in the early stages of a stroke, in his case caused by hemorrhage from his AVM.

There are two types of stroke: ischemic and hemorrhagic. Ischemic strokes occur when the blood flow to the brain is stopped by a blood clot or by low blood pressure throughout the body. If you are talking to a medical professional, they may refer to the formation these blood clots in one of two ways, either thrombosis or embolism. A thrombosis is a clot that forms in an artery or vein and stays in the place where it forms. An embolism is a clot that forms in one place in the body (often in the heart) and then travels somewhere else (usually the brain), and becomes trapped in an artery.

There are other sources of emboli besides blood clots, such as broken off bits of arterial plaque, fatty emboli which can occur after surgery or broken bones, amniotic emboli after childbirth, and bacterial emboli from an infection in the heart called endocarditis. The most common emboli is a clot that forms in the heart of a person in atrial fibrillation and travels to the brain.

The result for all forms of emboli is the same: lack of blood flow beyond the embolus causes a loss of oxygen and nutrients to the body's tissues. This is called ischemia (pronounced iss-scheme-ee-uh), or in the brain, ischemic (iss-scheme-ick) stroke. The other way an ischemic stroke can occur is if there is reduced blood flow to the brain, such as when a person is in cardiac arrest or has great blood loss from a major trauma. In these cases there is too little blood getting to the brain, which causes a loss of oxygen and nutrients to the cells and they die. It is known that about 85-90% of strokes annually are due to ischemic events.

A hemorrhagic stroke is a form of stroke that occurs when a blood vessel in the brain ruptures or bleeds. Like ischemic strokes, hemorrhagic strokes interrupt the brain's blood supply of oxygen and nutrients because the bleeding vessel can no longer carry the blood to the brain tissue. As the bleeding continues, it causes increased pressure in the brain, which physically impinges on the tissue and further restricts blood flow into the brain. For this reason, hemorrhagic strokes are more dangerous than the more common ischemic strokes.

There are two types of hemorrhagic stroke: intracerebral hemorrhage, and subarachnoid hemorrhage; Senator Johnson suffered from an intracerebral hemorrhage from a ruptured AVM. Intracerebral hemorrhage (ICH) is bleeding directly into the brain tissue, forming a gradually enlarging pool of blood. A Subarachnoid hemorrhage is bleeding into the cerebral spinal fluid in the space between the brain lining and the brain itself.

Unfortunately most AVMs are not found until they cause a problem, or they are discovered accidently because the brain is scanned for another reason. Senator Johnson was very lucky; his AVM was discovered early on and surgery was performed right away, giving him the best chance of a full recovery.

Despite the commentary from the newsies and political pundits, it is much too early to speculate on Senator Johnson's ability to make a full recovery or whether or not he will resume his duties in Washington. In an interesting side note, in 1969 another South Dakota senator, republican Karl Mundt, suffered a stroke while in office. Mundt continued to serve until the end of his term in January 1973, although he was unable to attend Senate sessions and was stripped of his committee assignments by the Senate Republican Conference in 1972. Senator Johnson, who was elected in 1996, holds the same seat previously held by Mundt.

Personal stroke prevention is similar to heart disease prevention: controlling high blood pressure, blood sugar and blood cholesterol levels, not smoking, and getting regular exercise all help to prevent stroke.

It is also important for you to recognize the signs and symptoms of stroke in others, so that you can assist them to seek early treatment. In the same way that early intervention in heart attack saves muscle, early intervention in "brain attack" can save brain cells.

Researchers at the University of North Carolina-Chapel Hill School of Medicine developed this one-minute, three-step stroke assessment test to enable bystanders to quickly screen for a possible stroke diagnosis. Learn this 3-step stroke assessment and pass it on to all your friends:

You may remember the steps to this test by thinking of the first three letters of the word stroke, S-T-R

S: Ask person to "Smile broadly, showing your teeth." This "smile test" is to look for one-sided facial weakness or paralysis, shown as a drooping on one side of the lips.

T: Ask the person to "Talk" to you by repeating a simple phrase, such as "don't cry over spilled milk, " or "it is a rainy day." This is a check for difficulty speaking or understanding speech or following basic instructions.

R: Ask person to close their eyes, Raise their arms in front of them and hold them out for a count of ten. This is to test for arm weakness or paralysis (if standing it can also test for leg weakness, paralysis, dizziness, or loss of balance.)

If any or all of the above are noted to be true, the person should be taken by ambulance to the nearest emergency department for evaluation for a stroke. Doing this quickly could prevent a person from living with a lifetime of neurological deficits or from death.
For more information, please see the Web MD Stroke Health Center

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