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April 27, 2006
What causes high blood pressure?
Q I have had high blood pressure for years. I asked my doctor what causes it. He said he did not know and that nobody knows. Maybe you can help.
A Close to 30 per cent of the adult North American population has high blood pressure — hypertension. About 94 per cent of those people have essential hypertension, the kind of blood pressure elevation for which there isn’t one definite cause.There are, however, things that contribute to its emergence. A diet loaded with salt and relatively poor in potassium, a couch potato lifestyle, obesity and the family genes work together to raise blood pressure. Primitive people who spend most of their waking hours hunting for food and whose diet is low in salt rarely have high blood pressure.
Doctors do know why blood pressure rises. It comes about from artery constriction. All arteries, even the smallest, are encircled with tiny muscles that can contract and narrow their diametre. When that happens, blood pressure goes up. It’s the same effect that occurs when you squeeze a hose. Water pressure behind the section that’s squeezed goes up.
Secondary hypertension is the kind of blood-pressure elevation for which there is an identifiable cause. It constitutes only about six per cent of all high blood pressure cases. Tumours of the adrenal gland, a kinking of the artery leading to one of the kidneys (renovascular hypertension) and an abrupt tapering of a part of the aorta (coarctation) are examples of things that lead to secondary hypertension. This kind of high blood pressure can usually be cured, and looking for the signs of secondary hypertension always pays off. Blood pressure that doesn’t respond to usual treatment or high blood pressure in young people suggests the possibility of secondary hypertension.
Q I have been chewing tobacco for about 30 years. I don’t spit it out but swallow it. I chew about one can a week. I have an enlarged spleen and wonder if the chewing tobacco has anything to do with it. Does it?
A Chewing tobacco is not likely related to an enlarged spleen. It is related to many other conditions.
It leads to more sustained blood levels of nicotine than does smoking cigarettes. Nicotine accelerates atherosclerosis (artery hardening), increases stress on the heart, raises cholesterol and raises the risk for clots to form within blood vessels.
Damage to the heart is less with chewing tobacco than it is with cigarette smoking, but it is much greater than the heart damage that might occur to nonchewers.
The possibility of mouth cancer is 50 times greater for tobacco-chewers than it is for those who do not use it. It can also produce gum and tooth disease.
Q I hope you can shed some light on Scheuermann’s disease. When my daughter was in the eighth grade and had to use crutches for a sprained ankle, she experienced back pain. An orthopedic surgeon suggested physical therapy, but the pain continued after the ankle healed. She had several tests, and finally a diagnosis of Scheuermann’s disease was made. My daughter is now a college freshman and still has pain. Do you have any suggestions?
A Scheuermann’s is a collapsing of the front part of one of the vertebrae (backbones), usually in the upper back. Physical therapy can often ease the pain and lessen any back deformity. Braces are sometimes necessary. Scheuermann’s only happens to children and teenagers. Pain almost always stops when growth stops. If pain and deformity are severe and unresponsive, surgery is considered.
Dr Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write to him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com.
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