How common is high blood pressure in children? I was recently told by a friend that her child, who is almost ten years old, is on medication for hypertension. This surprised me greatly because I thought high blood pressure in children is uncommon.
Nearly one out of every six North Americans will develop hypertension (high blood pressure). It is often called the "silent killer" because it goes undetected. If left untreated, it may lead to permanent damage of organs such as eyes, kidneys, heart and brain.
Children and adolescents are not immune to hypertension; nearly 5% of children have sustained high blood pressure. A few decades ago, medical students were told that the most common reason for high blood pressure in children was kidney diseases; now the top reason is obesity. With the increased incidence of obesity, the problem of hypertension has become even more prevalent in recent years.
Unfortunately, hypertension too frequently goes undetected. In a recent study (published in JAMA Vol. 298 No. 8, August 22/29, 2007), it was shown that hypertension in children is often not diagnosed. The study involved 14,187 children and adolescents aged 3 to 18 years. They were observed at least three times for well-child care visits between June 1999 and September 2006, in a large academic urban medical system in northeast Ohio. After electronic medical records were reviewed, it was shown that 3.6% of the patients met the criteria for hypertension. But in only 26% of those patients was the diagnosis documented.
Most experts agree that starting at age three children should have their blood pressure checked at least once a year, usually during well-child visits. The accuracy of these measurements may be questioned as readings can vary significantly with the size of the blood pressure cuff, patient positioning, the clinical setting and the equipment used. Moreover, one reading of high blood pressure is not sufficient to make the diagnosis. Rather, the patient should have a consistently high value obtained at three or more separate office visits at least 1 week apart.
Although most pediatricians do not wear white coats anymore, there is a condition known as "white coat syndrome". It refers to patients who have high blood pressure in the clinician's office, induced by anxiety and stress. But then when the child’s blood pressure is checked at home or at school it is normal.
Hypertension in children is defined according to a patient's age, gender and height. Given children grow at different rates, pediatricians use percentiles which alert them to the possibility of hypertension in children as young as one year of age.
When the readings are at the 95th percentile for height, it’s time to be concerned. For example, if a 5 year old boy has a reading of 116/74, he is at the 95th percentile. Specific values of readings at the 95th percentile for boys are: 123/82 at age 10; 132/84 at age 14; and 140/89 at age 17. Some values of blood pressures at the 95th percentile for girls are: 113/74 at age 5; 122/80 at age 10; 129/84 at age 14; and 132/86 at age 17. (Note: The top number represents the systolic value when the heart pumps; the bottom value reflects the pressure when the heart rests. The units are in mm of mercury).
A number of children will have a positive family history of hypertension. These patients are often undiagnosed when clinicians ignore this history or when electronic records are not
programmed to display clinic-alert flags for at-risk patients. One of the supposed benefits of newer technology in doctors’ offices, where paper records are replaced with electronic tools, is more accuracy in practicing preventive medicine, such as picking up subtle yet critical abnormalities early in life.
In addition to poor lifestyle choices – such as ingesting unhealthy snacks containing too much sugar and salt, being inactive physically, and spending excessive amounts of time playing video games, watching TV or surfing the Internet - other causes of high blood pressure in children must be considered. Being born prematurely and a low birth weight put patients at a higher risk as does a history of congenital heart disease, some endocrine conditions, and certain urinary and kidney problems. In adolescents, smoking, drinking, and the use of muscle building steroids may set the patient up for hypertension.
Children who snore deserve special attention, especially when they are overweight and suffer from obstructive sleep apnea (OSA). OSA affects 1 to 3% of the preschool population.
Compared with non-obese children, those who are obese are approximately three to five times more likely to have hypertension.
The signs and symptoms of high blood pressure are often silent, and do not appear until the blood pressure rises to dangerously high levels. These symptoms may include headaches, visual changes, dizziness, shortness of breath and fatigue. When a child is found to show signs of an enlarged left ventricle (the chamber of the heart which works the hardest when there is hypertension), it becomes important to treat this child aggressively with medications along with lifestyle changes.
Medications for high blood pressure include diuretics, beta blockers, calcium channel blockers and angiotensin converting enzyme (ACE) inhibitors. All of these have various side-effects, and are certainly more expensive than lifestyle changes.
Lifestyle changes for hypertensive children and adolescents include weight control, healthy nutrition (a diet rich in fruits and vegetables) and at least 30 to 60 minutes of aerobic physical activity each day of the week. Salt intake must also be reduced to 2 or 3 grams per day.
Families, who struggle to get the suggested 5 to 10 servings of fruit and vegetables per day into their picky eaters, can try hard for a maximum of 6 months by using resources such as www.5to10aday.com and the help of a pediatric nutritionist. But if these fail, it becomes critically important to use a high quality fruit and vegetable supplement which provides consistency. However, fruits and vegetables do not provide vitamin D; low levels of vitamin D may be associated with a higher risk of hypertension. So, taking a daily vitamin D3 supplement must be considered, especially in patients who live as far north of the Equator as Calgary, where they cannot depend on sunshine for healthy vitamin D levels.
Undiagnosed or untreated hypertension in childhood leads to high blood pressure in adulthood, putting adult patients at risk for stroke, heart attacks and kidney disease. A lifetime of good health must start in childhood. Knowing your child's blood pressure is one good first step to take.
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An informed parent is ... an empowered parent.