Q: You say my 8-year-old’s blood pressure is too high. It’s only 115/80! How do you know that’s too high, and what are you (and we) going to do about it? Isn’t high blood pressure an adult problem?
A: High blood pressure, or hypertension, has been recognized as an important adult health problem for as long as blood pressure has been measured. And that’s been 130 years – the Viennese physician Samuel Siegfried Karl Ritter von Basch is said to have invented the first sphygmomanometer (blood-pressure monitoring device) in 1881 after a stint as a military surgeon in Mexico.
When I was starting in medicine, most hypertensive children had a problem of their kidneys, or occasionally of their thyroid or adrenal glands – so-called secondary hypertension. In other words, the kidney, thyroid or adrenal disease was the primary cause, and the high blood pressure, the secondary result. Most hypertensive adults, like me, have “primary” or “essential” hypertension – no clear cause identified. Although now more children and especially adolescents are being identified with primary hypertension, it is still very important for children found with high blood pressure to be evaluated for another cause, especially kidney disease.
There have been advances in measurement of blood pressure since Basch’s time, of course, but the measurement is still difficult and beset by controversy. Many clinics, like the one where I work, have electronic blood pressure monitoring devices; they’re quicker than the old cuff and stethoscope. But the gold standard hasn’t changed much since the beginning of the 1900s – it’s still a mercury-filled measuring device, a properly-sized cuff and a stethoscope to hear the pulse. You’ll notice I said “properly sized” – too small a cuff will give too high a blood pressure reading.
Then there’s the problem of the white coat. Of course, I can’t imagine why anyone should be anxious when they see a doctor (I see them every day), but some patients are, and the anxiety drives up their blood pressure. So with children – perhaps yours included – the problem may have been “white-coat hypertension.” The remedy is to measure several times, on separate occasions, particularly if the measurements can be taken in situations less likely to cause alarm and anxiety.
All right, let’s suppose that your child’s blood pressure is really 115/80 after several well-done measurements. How do we know that’s too high? This isn’t as easy as it is for children as for adults, where “one size (more or less) fits all.” For children, I have two tables, with a total of 1,904 numbers in them to tell me the systolic (higher number) and diastolic (lower) values that one should worry about.
To do this properly, we need to know the child’s age, sex, height and blood pressure as well as a growth chart to see how the child compares with his peers. As it turns out, for an average-height 8-year-old, a systolic pressure of 115 is above the 90th percentile (meaning that 90 out of 100 children of that age and height will have lower blood pressures), and a diastolic of 80 is above the 95th percentile. Children above the 95th percentile for age and height are said to have hypertension; those between the 90th and 95th, to have prehypertension.
So then what? First, his doctor should look for those primary causes, making sure there isn’t any kidney or other disease at the root of the problem. She should then look for associated problems: the main reason that hypertension is on the rise is that much of it is associated with being overweight (and sometimes with diabetes as well). She should look to make sure the heart hasn’t yet been affected.
If there is a primary cause like kidney disease, it needs to be dealt with first. But if the problem is primary hypertension that isn’t extremely severe and potentially immediately dangerous, the first steps are to work on diet (decreasing salt, fats and calories) and on exercise (exercise alone reduces elevated blood pressure).
If those don’t work and the blood pressure remains high, your doctor may prescribe medication. The medicines used in adults are also used in children – they fall into a number of categories, and studies are under way, but not yet available to determine which category is best to start with in kids.
Why should you be concerned? Unfortunately, untreated hypertension in kids leads to hypertension in adults, and there can be damage to a number of body organs, including the kidneys, brain, and especially the heart. In childhood that damage is usually silent but cumulative, so it’s worth treating. A treasured relative of mine recently died of a hypertension-associated stroke. She wasn’t a child, but the beginnings of her hypertension may have come half a century ago.
Lance Chilton, M.D., is a pediatrician at the Young Children’s Health Center in Albuquerque, associated with the University of New Mexico. He is happy to take questions at 272-9242 or lancekathy@gmail.com.
