Formerly considered an adult disease, high blood pressure (hypertension) is being diagnosed in more and more children. An estimated 5 percent of children in the United States have high blood pressure, a condition in which the heart and blood vessels are being overworked.
High blood pressure can be caused by a number of factors, including salt intake, obesity, kidney problems or other diseases. Recent studies have found that the average blood pressure of American adolescents and teens is on the rise – a disturbing trend considering the long–term impact of high blood pressure on risk of heart disease.
High blood pressure levels are different for children than for adults. Whereas adult blood pressure levels are standard, children’s blood pressure readings are measured according to their height, gender and age. Children who have elevated blood pressure relative to their peers may be diagnosed with high blood pressure.
Physicians also take into consideration that children tend to express extremes of emotion, which affects blood pressure. If blood pressure is only temporarily high, treatment is not usually necessary. A diagnosis of high blood pressure in children usually requires that elevated readings be obtained on three separate tests, given weeks or days apart. The American Heart Association (AHA) currently recommends that children over the age of 3 receive yearly blood pressure measurements.
Once elevated blood pressure is confirmed, the treatment among children may be different than treatment for adults. In adults, most blood pressure is “essential,” or occurs without a known reason. By contrast, most elevated blood pressure in prepubescent children under 10 years of age is secondary to another, underlying cause. Among adolescents and teenagers, however, the number of patients afflicted with essential blood pressure rises.
It is important when dealing with children to determine if there is an underlying condition causing the high blood pressure and design a treatment for that condition. In recent years, obesity and being overweight have become a major health problem among adolescents and children, which is thought to be contributing to a rise in blood pressure across all age groups. This is especially dangerous because studies have shown that overweight children with high blood pressure are much more likely to become adult heart disease patients. Other conditions that may contribute to high blood pressure include kidney disease and endocrine disorders.
Medication is usually not prescribed for children unless there is significant high blood pressure or organ damage. A child or adolescent with high blood pressure should be treated by a pediatric cardiologist or a pediatrician with special knowledge and experience in the treatment of high blood pressure in this age group.
About blood pressure and children
Blood pressure normally increases with age during childhood. As in adults, higher than normal blood pressure readings in children (pediatric hypertension) is a sign of imbalance or disease. However, there are several important blood pressure issues that differ for children:
Primary vs. secondary. In adults, nearly all cases of high blood pressure are primary (or essential) hypertension – meaning that the high blood pressure occurs on its own for no known reason. By contrast, the majority of pre-pubescent children under 10 years of age who are diagnosed with high blood pressure have secondary hypertension (high blood pressure caused by a separate underlying condition). Usually, treatment of the condition causing the hypertension leads to a return to normal blood pressure readings. Essential hypertension, however, is more common among adolescents and teenagers. This may be connected to the society-wide problem of weight gain and sedentary lifestyles among adolescents and teenagers.
Normal ranges. In adults, there is one set of established blood pressure ranges to indicate whether readings are high, borderline, normal or low. In children, however, the measurement of blood pressure is somewhat different. Children are measured on a sliding scale using height, gender and age and compared to their peers. High blood pressure is diagnosed among children who have elevated readings relative to their peers, or who are in higher percentiles. For example, children who are in the 95th percentile (higher blood pressure than 95 percent of their peers) will be diagnosed with high blood pressure.
Accuracy of readings. Blood pressure fluctuates normally in the course of daily life for both adults and children. However, children’s blood pressure levels may be more sensitive to stress or unfamiliar situations, such as a doctor’s visit or the blood pressure reading itself. Therefore repeated testing over time and in a variety of settings is usually necessary to the diagnosis of high blood pressure in children. In fact, the National Heart, Lung and Blood Institute recommends that high readings must be found on at least three separate occasions before a diagnosis of pediatric hypertension is made.
Measuring blood pressure. Blood pressure measurements are taken using a stethoscope and an arm cuff (sphygmomanometer). The arm cuff used to measure blood pressure in children must be appropriate to the child’s size or the reading may not be accurate. For this same reason, home blood pressure monitoring devices designed for adults may not accurately measure blood pressure in children. Ambulatory blood pressure monitoring (ABPM) is a test in which a portable device that takes blood pressure readings regularly is worn by the patient for an extended period (usually 24 hours). While it is becoming increasingly common in adults, ABPM is not yet recommended for children.
The link between pediatric hypertension and high blood pressure in adulthood is not completely understood. It is increasingly clear, however, that hypertension among children predicts hypertension among adults. Studies have shown that children with essential hypertension, or elevated blood pressure that has no cause, are more likely to become adults with heart disease. Other studies have shown a correlation between elevated blood pressure in children and risk factors for coronary artery disease, such as calcification in the arteries and stiffness of the arterial walls. For these reasons, it is important to identify young patients with high blood pressure and treat it as early as possible.
High blood pressure can be found in children as young as newborns, but such cases are usually secondary to another condition. Recent studies have found that the average blood pressure of American adolescents and teens is on the rise, a disturbing trend that many researchers believe is connected to the increasing rate of obesity and being overweight among American children and adolescents. This is particularly worrying since past research suggests that for every 1 to 3 mm Hg (millimeters of mercury) rise in blood pressure, a child has a 10 percent increase in the risk of developing high blood pressure in adulthood.
Children with hypertensive parents are also at a greater risk of developing high blood pressure, and the risk increases further if more than one parent is hypertensive. Low birth-weight babies who gain weight rapidly may also have an increased risk for developing high blood pressure as adults.
The American Heart Association (AHA) currently recommends that children over the age of 3 receive yearly blood pressure measurements.
Risk factors and causes in children
As with adults, the causes of primary (or essential) hypertension in children are unknown. Children with a family history of high blood pressure may be at increased risk of developing primary hypertension. However, this condition is far less common in children than adults, in whom about 95 percent of hypertension cases are primary. While the cause of primary hypertension is unknown, it is believed that genetics and lifestyle factors such as diet and smoking may play a role.
Secondary hypertension (high blood pressure caused by a separate underlying condition) is the most common form in children under the age of 10. There are a number of factors and conditions that can lead to secondary hypertension in children, including:
Childhood obesity. It is estimated that 16 percent of school age children in the United States are overweight, and obesity is one of the more common causes of high blood pressure in children. In fact, some researchers believe that the significant rise in children's blood pressure levels in the last 10 years is a direct result of rising body weights in adolescents and teens. High blood pressure is nine times more likely in obese or overweight children than in other children.
Lack of physical activity.
Elevated salt intake. Salt consumption not only directly impacts blood pressure, but can also affect kidney function later in life.
Childhood diabetes.
Renal kidney disease, such as renal artery stenosis. The kidneys play a role in regulating blood pressure levels. Therefore, disease or damage to these organs can cause hypertension. Kidney problems usually result in both diastolic and systolic blood pressure readings that are very high.
Coarctation of the aorta, in which the aorta is pinched, constricted or narrowed at some point along its length. This results in high blood pressure in the upper body and low blood pressure in the lower body.
Other congenital conditions.
Lead poisoning.
Abnormal levels for children
Blood pressure usually increases as children grow. Since children do not grow at the same rates, however, age alone is not enough to determine normal levels for a child’s blood pressure. Height and gender are also considered, both to avoid misdiagnosis of children who are tall for their age and to avoid missing hypertension in very short children.
It is common for people to have elevated blood pressure readings when these measurements are taken in a medical setting. Called white coat hypertension, many patients, young and old, become nervous by the surroundings, the potentially serious nature of a medical office visit or other concerns. These anxieties may cause a temporary rise in blood pressure that leads to a misleading reading. To reduce the risk of misdiagnosis, readings may be taken at several times during the office visit or again at a later date.
While any diagnosis of high blood pressure is made with the help of multiple blood pressure readings over time, additional precautions may be taken with children. Typical childhood reaction to medical tests (e.g., agitation, fear, crying) can all raise blood pressure readings significantly. Multiple testing is therefore common and home blood pressure monitoring may be advised to aid in diagnosis.
When diagnosing high blood pressure in children, physicians compare the results of their tests against the child’s peer group, taking into account the child’s gender, age and height. Based on this, the National High Blood Pressure Education Program Working Group has developed categories to help define blood pressure. They include:
Normal. Systolic and diastolic blood pressure are less than the 90th percentile.
Prehypertension. Systolic and/or diastolic blood pressure are greater than or equal to the 90th percentile, but less than the 95th percentile, or if blood pressure exceeds 120/80 mmHg even if less than the 90th percentile.
Stage 1 hypertension. Systolic and/or diastolic blood pressure between the 95th percentile and the 99th percentile.
Stage 2 hypertension. Systolic and/or diastolic blood pressure greater than or equal to the 99th percentile.
The systolic and diastolic readings are of equal importance. If there is a disparity, the number with the higher value is used to determine high blood pressure.
The table below provides an example of the measurements physicians use to determine high blood pressure in children. The readings given are for children in the 95th height percentile (e.g., taller than 95 percent of their peers), and for the children at the older end of a given age range. The blood pressure readings given would place a child above the 90th percentile in blood pressure, which may indicate a diagnosis of prehypertension.
The table below provides highlights of the guidelines used to determine abnormally high blood pressure in children. The cut–off points listed are for general information only. This chart does not provide the detailed breakdowns, which vary by a child’s height, used by physicians when making a diagnosis. People are encouraged to speak to their physicians about individual cases. NOTE: All blood pressure measurements are in millimeters of mercury (mm Hg).
Age
Boys
Girls
Normal
High
Normal
High
1
< 103/54
>= 106/58
< 103/56
>= 107/60
2 to 3
< 109/63
>= 113/67
< 106/65
>= 110/69
4 to 5
< 112/70
>= 116/74
< 109/70
>= 113/74
6 to 7
< 115/74
>= 119/78
< 113/73
>= 116/77
8 to 10
< 119/78
>= 123/82
< 118/76
>= 122/80
11 to 12
< 123/79
>= 127/83
< 122/78
>= 133/90
13 to 14
< 128/80
>= 132/84
< 125/80
>= 136/92
15 to 17
< 136/84
>= 140/89
< 128/82
>= 132/86
Over 18
same as adults
Source: Adapted from the National Heart Lung & Blood Institutes Blood Pressure Tables for Children and Adolescents
In order to be considered “normal” BOTH the upper number systolic pressure and the lower number diastolic pressure of a blood pressure reading must be below the 90th percentile for that child's age, height and gender. However, if EITHER number is above the 95th percentile, then a diagnosis of hypertension may be made. As with adults, readings higher than normal but not yet within high ranges are considered prehypertension.
The relationship between diastolic and systolic readings, as well as the numbers themselves, can be helpful in analyzing blood pressure readings. For example, kidney problems generally cause extreme highs in both diastolic and systolic blood pressures. Therefore, this cause is less likely in a prehypertensive child whose diastolic pressure is normal.
Research findings for children
Studies on children and high blood pressure have produced some of the following findings:
Average blood pressure of American adolescents and teens (ages 8 to 17) is on the rise compared to 10 years ago – especially among black American and Mexican-American boys. Some researchers believe this is connected to the rising rate of overweight and obese adolescents and children.
Overweight children are at an increased risk of high blood pressure. In fact, more than ten percent of overweight children may also be hypertensive.
Regular drinking of high caffeine beverages, such as soda, may increase blood pressure levels in teens. Again, black Americans appear to be more susceptible to caffeine's effect on blood pressure.
Stress management techniques, such as meditation, may help teenagers with higher than normal readings lower their blood pressures.
Children who are breast-fed as infants may have lower blood pressure readings in adolescence. Also, the amount of salt that a baby consumes in infancy can affect blood pressure levels later in life.
Studies have shown that supplementing infant formula with polyunsaturated fat (e.g., omega-3 fatty acids) may help prevent high blood pressure from developing later on in childhood.
A high-salt diet may also impact blood pressure in children. Salt consumption can also affect kidney function later in life. Many prepackaged, processed and “fast” foods are high in fat and can contribute to obesity as well as having high sodium content.
Over time, some hypertensive children may develop an enlarged heart, dilated cardiomyopathy or enlarged kidney. In general, this is a sign that the enlarged organ is working too hard.
Another type of muscle thickening that may be caused by hypertension is called left ventricular hypertrophy (a thickened left ventricle). This condition is a known risk factor for future heart attack, heart failure or stroke. Although it may not cause any symptoms, it should be considered as a risk factor for future heart disease. Therefore, hypertensive children should have their left ventricles measured regularly usuing a echocardiogram.
The blood pressure of a young person can help in predicting that individual’s future risk potential for heart disease. Higher blood pressure when a person is young is associated with higher risk of developing elevated blood pressure and/or heart disease later in life.
Studies show that lead exposure (e.g., from lead-based paint, leaded gasoline) in childhood can increase the risk of developing high blood pressure (and as well as neurologic and developmental problems) later on and into adulthood.
Treatment options for children
Generally, high blood pressure in children is not considered serious if transient or temporary. When high blood pressure in children is being caused by a separate underlying condition (secondary hypertension) the primary condition is the focus of treatment. In most cases, when the primary issue (e.g., obesity, kidney disease) is under control, then the child's blood pressure readings will return to normal. For children with high readings not due to another condition (primary or essential hypertension), treatment may be necessary. In such cases, treatment of high blood pressure in children is essentially the same as it is for adults. Hypertensive children will need treatment if they have any signs of organ damage such as:
An increased thickness of the heart’s left ventricle(left ventricular hypertrophy)
Retinopathy (a disease of the eye)
Nephropathy (a kidney disease)
Cerebrovascular disease (a brain-related disease)
Most hypertensive children can be treated using lifestyle modifications such as:
Achieving and maintaining a healthy weight (a crucial step)
Controlling diet, including lowering intake of fats and oils and salt and increasing fruit and vegetables
Putting the child on the DASH diet (Dietary Approaches to Stop Hypertension)
Exercising regularly (e.g., regular aerobic activity), but avoiding weight-lifting
Controlling stress
Avoiding caffeine
Avoiding smoking and exposure to secondhand smoke
Controlling diabetes (the combination of diabetes and hypertension can lead to serious medical complications in the future)
In children with severe and persistent high blood pressure that does not respond to lifestyle changes, antihypertensive medications may be recommended. While many of the same medications used in adults are also used for children, the dosage will usually vary.
Questions for your doctor
Preparing questions in advance can help parents to have more meaningful discussions with their child's physician regarding their conditions. Parents may wish to ask their child's doctor the following questions related to high blood pressure in children:
What is my child's blood pressure?
Is my child's blood pressure too high?
Is it possible my child's blood pressure appears to be high because he/she is nervous? Are there any other tests my child can take to get a more accurate reading?
Is my child at high risk for high blood pressure?
Does high blood pressure put my child at risk for any cardiovascular conditions? Which ones?
Could my child be taking any medications that might be contributing to his/her high blood pressure?
Are there any medications my child can take to lower their blood pressure? Are there side effects associated with any of these medications?
Are there any lifestyle changes that can lower my child's blood pressure or reduce his/her chances of developing high blood pressure? Does my child need to lose weight?
Could my child's high blood pressure be the result of stress in his/her life?
How urgently does my child need to lower his/her blood pressure?
