Accidents in the Brain

Each year, by conservative estimate, at least 175,000 people in the U.S. die of strokes--accidents to the arteries in the brain. Among 1,800,000 survivors of strokes, a large number are severely para lyzed, and many drag out a hopeless existence, often requiring the care of three or four persons. Yet until recently, despite their frequency and severity, strokes have been neglected by medical researchers because it seemed that so little could be done for their victims. Last week Cornell University's Dr. Irving S. Wright reported the hopeful findings of a just-concluded conference at Princeton (paid for by the National Heart Institute, sponsored by the American Heart Association) of 50 assorted specialists--neurologists, neuro surgeons, physiologists, pathologists, hematologists, internists. Gist of their conclusions: much more can be done to determine the exact nature of a stroke, and anticoagulant drugs show promise as a means of warding off recurrences.

All strokes damage the brain by shutting off the blood supply to cells. According to how this damage happens, strokes are divided into three major types:

1) shutdown in a brain artery by a clot,, called a thrombosis if the clot forms at the site, or an embolism if the clot is formed elsewhere--usually the heart--and travels through the arteries to the brain;

2) hemorrhage, or a blowout in a weakened artery wall; 3) aneurysm, a ballooning of weakened artery wall, which causes pressure on surrounding brain tissues. For all three categories, the experts reported advances in research and diagnosis as well as treatment.

Research Leads. Traditionally, the brain has been supposed to require a superabundant blood supply, but the difficulty has been to determine how much. Stockholm's Dr. Gustav Nylin reported that he had injected red blood cells labeled with radioactive thorium into healthy test subjects, discovered that the major blood flow through the brain is normally much less than previously believed--and notably less than in other body tissues. A series of blood-flow readings may help in the evaluation of treatment.

Cleveland's Dr. Arthur C. Corcoran checked stroke victims' blood pressure, found that abnormally high pressure predisposes a person to strokes, especially of the hemorrhagic type. In such cases it would be dangerous to use anticoagulant drugs (because of the risk of further hemorrhage); the Cleveland Clinic researchers have found that they could lower the blood pressure with hypotensive drugs, arid later use anticoagulants safely to minimize the risk of subsequent strokes.

Arteriosclerosis and specifically atherosclerosis (the form of the disease in which arteries are plugged by mushy, fatty deposits) is "as great a problem" in stroke victims as in coronary artery disease, said Dr. Wright. A stroke may either precede or follow a heart attack: the two are often associated, and the same patient is likely to have atherosclerosis in both cerebral and coronary arteries. As in heart disease, female sex hormones seem to exert a protective effect (reflected in the relative immunity of premenopausal women), but they cannot be given to men without feminizing them. Needed: a synthetic hormone that affords protection without feminization. Several laboratories are trying to produce one.

Diagnostic Clues. A major difficulty in deciding on treatment of a stroke victim lies in determining the type of stroke --the right treatment for a thrombosis would he dead wrong after a hemorrhage. To find which it is, several researchers agreed that spinal-fluid taps should be taken routinely: the dangers of tapping are less than formerly thought. A second diagnostic advance comes from use of radiopaque dyes, which are injected into arteries leading to the brain: X rays help to locate obstructions to circulation resulting from thromboses and especially aneurysms.

The researchers' consensus: usually, not enough attention is paid to the warning signs afforded by "little strokes"--tempo-rary weakness of an arm. or impairment of speech or vision, which may result from a minor arterial accident and often go undiagnosed. The signs may last for only a few minutes, or for. days or weeks. In either case, they signal the need for a thorough checkup.

Against Recurrences. Most stroke victims go from one attack to another. Not all are serious (some patients have had two or three a day for several months, for a total of hundreds), but there is always the danger that the next may be fatal. To guard against recurrences, Dr. Wright and colleagues have pioneered with anticoagulant drugs (mostly coumarin derivatives, such as Dicumarol, Tromexan, Marcumar), which reduce the blood-clotting tendency in patients who have had embolism or (in a few cases) thrombosis. Dr. Ellen McDevitt described how 83 patients were observed for periods on and off anticoagulants. In 2.503 patient-months without the drugs, there were 295 clotting episodes, 114 of which affected the brain arteries. In 2,022 patient-months on anticoagulants, there were 68 thrombo-embolic episodes; only 15 of these affected the brain, and nine occurred when the patients were not taking as much of the drug as they should. Drs. Wright and McDevitt have seen some of these patients go more than ten years without any recurrences.

For cases of aneurysm requiring surgery, Toronto's Dr. E. Henry Botterell reported a new benefit from hypothermia --chilling the patient to 90DEG or even as low as 86DEG F. This not only reduces the brain's demand for blood, thus giving the neurosurgeon a drier field, but actually shrinks the brain so that it stays tidily in the skull, making the operation far easier and safer than when the brain bulges out under normal temperature and pressure.

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