In over nine patients out of ten with high blood pressure no
underlying
disease can be found. The term “essential hypertension” is sometimes used in
this case. This absence of a cause is not as surprising as might appear at first
sight. Blood pressure, like height or weight, is the result of many influences.
Just as in the case of stature, heredity is important. If your parents’ blood
pressures were on the high side, the chances of you also developing
hypertension are increased. The similarity with stature goes further than that
however. There is no clear division between normal and raised blood pressure,
in the same way that there is no separation between people who are tall and
those who are of normal height. It is not strictly correct, therefore, to talk of
individuals as “having” or “not having” essential hypertension although doctors
usually do this because it is convenient. There are borderline blood pressure
levels which would be regarded as hypertensive by some doctors but normal by
others, just as we differ in our definition of tallness or obesity. On rare occasions
a definable cause may be identified, such as narrowing of the artery to a kidney
of abnormal production of hormone from the adrenal gland. Occasionally high
blood pressure may be due to other forms of severe kidney disease. These
situations are very unusual however and can be easily identified by blood tests
and X-rays. Occasionally blood pressure may be worsened by medication. Some
tablets used in treating ulcers, arthritis or depression may raise blood pressure. If
you are taking medicine which your doctor may not know about (either bought
at a chemist’s shop or prescribed by another doctor), it is vital that you tell
your doctor. It is preferable to take it with you when you attend for blood
pressure measurement.