Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, May 10, 1994 TAG: 9405120007
SECTION: EXTRA PAGE: 6 EDITION: METRO
SOURCE: By DON COLBURN THE WASHINGTON POST
DATELINE: LENGTH: Long
Stroke is the third-leading cause of death among Americans, after heart disease and cancer, and the leading cause of serious disability in adults. On average, about one stroke a minute occurs in the United States, according to the National Center for Health Statistics.
There are two main types of stroke. The most common, responsible for more than 80 percent of cases, is caused by a clot or other blockage in the blood supply to the brain. The clot may be a thrombus (Greek for ``clot'') that forms in the wall of an artery supplying the brain - or an embolus (Greek for ``plug'') that forms elsewhere, often in the heart, and is carried by the bloodstream until it lodges in an artery in or near the brain.
The other main type of stroke is caused by bleeding in the brain. Called hemorrhagic stroke, it occurs when a blood vessel bursts from a head injury or an aneurysm, a weak spot in the artery wall that balloons out.
Either type can be fatal, but hemorrhagic strokes have a much higher fatality rate. Former President Nixon's stroke appeared to have been caused by a blood clot that blocked the blood flow to his brain, doctors said.
With any major stroke, a serious threat to life is the swelling within the skull. Since there is little room for the brain to expand, swelling causes pressure on sensitive brain tissues. The swelling comes from bleeding caused either directly by a hemorrhage or indirectly as damaged parts of the brain break down and start to leak.
A major stroke can happen with or without warning. The dancer and choreographer Agnes de Mille described her near-fatal stroke in 1975 this way in her memoir: ``I stood in the auditorium of the Hunter College Playhouse in New York City giving last-minute instructions to my dance company ... Suddenly I discovered that half of my body was dead.'' Though paralyzed on her right side, she recovered well enough to remain active for years as a choreographer and writer. She died last October at 88.
One way in which a stroke differs from a heart attack is that it lacks the obvious warning of pain.
``It doesn't produce any pain whatsoever,'' said Denise Barbut, director of the stroke center at the New York Hospital-Cornell Medical Center, where Nixon was hospitalized after his stroke. ``Brain death has no pain. With heart attack, everybody and his uncle knows you get a chest pain.''
Prompt medical attention is critical, because the chances of reversing damage to nerve cells in the brain fade within a few hours of a stroke. After that, only the symptoms can be treated.
Even 10 hours after a stroke, ``whatever damage is done is done, and you can't reverse dead brain tissue,'' Barbut said. She declined to comment specifically on Nixon's case.
Warning signals include a range of neurological symptoms, such as numbness in the arm, tingling around the mouth or in the hand, paralysis on one side of the body, a blind spot in one eye, slurred speech, clumsy fingers or stumbling feet.
The warning may come in simple disruptions of ordinary tasks, as when a person suddenly drops a teacup for no apparent reason, or can't button a shirt with one hand, or can't find words for a thought.
Barbut advised anyone with warning signs of a stroke to ``go to the emergency room ASAP and not just say I have a numbness in my arm and I'll take an aspirin and see how it is in the morning.''
Several factors markedly increase a person's risk of having a stroke: cigarette smoking, heart disease, diabetes and high blood pressure. Rates of stroke are also higher in males, African Americans and people with a family history of stroke.
Risk of a stroke also rises sharply in middle age. After age 55, the chance of having a stroke doubles with each successive decade, according to the National Institute of Neurological Disorders and Stroke.
The first goal in treatment of an apparent stroke is to stabilize the patient and pin down the diagnosis. A CT brain scan is often taken to determine the extent of the bleeding in the brain.
Several experimental drugs are being used selectively on stroke patients at leading medical centers around the country, in an effort to find ways of limiting the initial damage of a stroke. They include tissue plasminogen activator, or tPA, a synthetic ``clot bluster'' protein that is also used against heart attacks, and NMDA receptor antagonists, which help prevent swelling of cells.
But those drugs must be given almost immediately - within three to six hours - to be effective. Also, these still-experimental drugs cannot be given to patients with high blood pressure or certain heart conditions. Nixon, for example, was ruled out for use of NMDA receptor antagonists by his cardiologist because of a previous heart condition that made him vulnerable to the drug's side effects.
Conventional treatment of stroke includes use of drugs such as heparin to thin the blood, mannitol to reduce inflammation and warfarin to help prevent another clot from forming. Sometimes the patient is put on a ventilator to make breathing easier and more efficient. Once a patient is stabilized, doctors decide whether to switch to other medications - ranging from aspirin to stronger anticoagulants - to lessen the chance of another stroke.
Nixon already had been taking warfarin at the time of his stroke. Like more than a million Americans, Nixon had a heart condition called atrial fibrillation, or AF. The condition is not threatening in itself but increases the chance of stroke by allowing blood clots to form in one of the heart's upper chambers, or atria.
Once stabilized - usually within four to seven days - stroke patients may recover full or partial strength, sensation and other lost abilities, with sometimes arduous therapy and rehabilitation. Sometimes, paralysis remains permanent.
``Improvement can go on for up to six months,'' Barbut said, ``but most of it has happened by three months.''
by CNB