High blood pressure (hypertension) is persistently high pressure in the arteries.
Usually, high blood pressure in children, as in adults, has no identifiable cause.
During childhood, most children with high blood pressure have no symptoms, although symptoms may develop later.
Doctors measure blood pressure several times with a sphygmomanometer (a soft rubber cuff connected to a rubber bulb that is used to inflate the cuff and a meter that registers the pressure of the cuff) or sometimes with an automated instrument called an oscillometer
If children have high blood pressure, doctors often do tests to look for possible causes.
Treatment usually starts with lifestyle changes, but drugs are sometimes needed.
When blood pressure is checked, two values are recorded. The higher value reflects the highest pressure in the arteries, which is reached when the heart contracts (during systole). The lower value reflects the lowest pressure in the arteries, which is reached just before the heart begins to contract again (during diastole). Blood pressure is written as systolic pressure/diastolic pressure—for example, 120/80 mm Hg (millimeters of mercury), referred to as 120 over 80.
High blood pressure often begins during childhood. In the United States, about 2 to 4% of children have high blood pressure. Another 3 to 4% have blood pressure that is at the high end of normal. Worldwide, about 4% of children are estimated to have high blood pressure. The percentage of children with high blood pressure seems to be increasing, probably because more and more children are becoming overweight or obese.
In children under 13 years of age, the values that are considered high vary based on sex, age, and height. Thus, there is no clear-cut blood pressure that indicates high blood pressure for all children. Rather, elevated blood pressure is diagnosed if a child's blood pressure is the same as or higher than the blood pressure of 90% of children who are the same sex, age, and height.
In adolescents (13 years of age or over), blood pressure is classified as it is in adults:
Normal: Lower than 120 systolic blood pressure and lower than 80 diastolic blood pressure
Elevated: 120 to 129 systolic blood pressure and lower than 80 diastolic blood pressure
Stage 1 (mild) high blood pressure: 130/80 to 139/89)
Stage 2 high blood pressure: 140/90 or higher
The body has many mechanisms to control blood pressure. The body can change the following:
Amount of blood the heart pumps
Diameter of arteries
Volume of blood in the bloodstream
To increase blood pressure, the heart can pump more blood by pumping more forcefully or more rapidly. Small arteries can narrow (constrict), forcing the blood from each heartbeat through a narrower space than normal. Because the space in the arteries is narrower, the same amount of blood passing through them increases the blood pressure. Veins can constrict to reduce their capacity to hold blood, forcing more blood into the arteries. As a result, blood pressure increases. The kidneys can add more fluid to the bloodstream by excreting less water and sodium (salt). As a result, blood volume and thus blood pressure are increased.
To decrease blood pressure, the heart can pump less forcefully or rapidly, small arteries and veins can widen (dilate), and the kidneys can remove fluid and sodium from the bloodstream.
Causes of High Blood Pressure in Children
High blood pressure may be
Primary (no known cause)
Secondary (caused by another disorder such as a kidney disorder)
In children 6 years of age and older, primary high blood pressure is by far the most common cause, particularly among adolescents. In children under 6 years of age, especially those under 3 years, secondary high blood pressure is more common.
Primary hypertension
Although the cause is unknown, primary hypertension is more common among children who have the following risk factors:
Overweight or obesity (the most important risk factor)
Family history of high blood pressure
Male sex
Mexican-American or Black (in the United States)
Low level of physical activity
Excessive amount of salt and calories in their diet
Underweight at birth or premature birth
Social risk factors such as child abuse, violence among family members, or food and/or housing insecurity
Smoking tobaccovaping products) and exposure to secondhand smoke may also contribute to high blood pressure.
Secondary hypertension
Secondary hypertension has an identifiable cause. Sometimes when the cause is treated, blood pressure returns to normal.
The most common causes of secondary hypertension in children are
A kidney disorder, such as glomerulonephritis, a kidney infection, a blockage in the urinary tract, polycystic kidney disease, or a disorder that affects blood vessels to the kidneys
Heart and other blood vessel disorders, such as coarctation of the aorta or arteriovenous fistula
Hormonal disorders, such as an overactive thyroid gland (hyperthyroidism)
Other causes of secondary hypertension include
Increased pressure within the skull (increased intracranial pressure)
Drugs, such as corticosteroids, anabolic steroids, oral contraceptives
Stress or pain
Stress or pain tends to cause blood pressure to increase temporarily, and blood pressure usually returns to normal after the stress or pain ends.
Other conditions that temporarily increase blood pressure include recent consumption of a caffeinated beverage, recent physical activity, and white coat hypertension, which is caused by the stress of visiting a doctor's office.
Symptoms of High Blood Pressure in Children
Usually, high blood pressure causes no symptoms in children. High blood pressure typically causes symptoms only after a vital organ is damaged, usually not for many years after blood pressure becomes high.
Thus, problems due to high blood pressure tend not to develop during childhood.
Rarely, high blood pressure in children severely damages vital organs because of a sudden hypertensive emergency. The organs that may be affected include the
Brain, which can result in deterioration of brain function, with drowsiness, confusion, seizures, and even coma
Heart, which can result in heart failure
Eyes, which can result in papilledema (swelling of the optic nerve) and bleeding in the retina
Kidneys, which can result in kidney failure
If untreated, a hypertensive emergency can be fatal.
Diagnosis of High Blood Pressure in Children
Measurement of blood pressure
Sometimes tests to identify the cause
Because the definition of high blood pressure in children depends on a child's age, sex, and height, there is no one value that is considered high. Consequently, doctors use charts that list the different values for boys and girls by age and height. These charts enable doctors to diagnose high blood pressure and to classify how severe it is.
For the most accurate readings, blood pressure is measured after children sit quietly in a chair for 3 to 5 minutes. Their back should be supported, and ideally their feet should be on the floor.
Blood pressure is usually measured with a sphygmomanometer (a soft rubber cuff connected to a rubber bulb that is used to inflate the cuff and a meter that registers the pressure of the cuff). Health care practitioners make sure the cuff fits the child's arm. The cuff is inflated enough to stop blood flow. Then practitioners deflate the cuff and use a stethoscope placed over the artery below the cuff to listen for the first pulse and then for the sound of no blood flowing (when the heart relaxes, between beats). Sometimes, doctors use an instrument called an oscillometer to measure blood pressure rather than using a sphygmomanometer and a stethoscope. The oscillometer records blood pressure automatically and quickly. If there is an abnormality, blood pressure is measured again using a sphygmomanometer and a stethoscope to confirm the measurement.
Doctors recommend that blood pressure measurements start when children are 3 years old. If young children have risk factors that increase their risk of high blood pressure (such as having a kidney or heart disorder, or having been born very prematurely), doctors start measuring blood pressure as early as possible and at each well-child visit.
If moderately high blood pressure is diagnosed, doctors recheck blood pressure within 6 months. If blood pressure is still high, lifestyle changes, such as an improved diet, more physical activity, and weight loss (if needed), are started. If blood pressure remains high over the next 6 months, children may be given an ambulatory blood pressure monitor, if possible, or could be referred to a specialist. An ambulatory blood pressure monitor is a portable battery-operated device, connected to a blood pressure cuff, worn on the arm. This monitor repeatedly records blood pressure throughout the day and night over a 24-hour period. The readings help doctors determine whether high blood pressure is present, how often elevated readings occur, and how severe they are.
If stage 1 hypertension is diagnosed, doctors recheck blood pressure within 1 to 2 weeks. If blood pressure remains at stage 1, pressure measurements are taken in an arm and in a leg to see whether there is a difference between them, a urinalysis is done, and lifestyle changes are recommended. Doctors recheck blood pressure in 2 to 3 months, and, if it is still at stage 1, the child should be referred to a specialist.
If stage 2 hypertension is diagnosed or children have stage 1 hypertension and symptoms, children are referred immediately to an emergency department or to a specialist for possible hospitalization.
Measuring Blood Pressure
Several instruments can measure blood pressure quickly and with little discomfort. A sphygmomanometer is commonly used. It consists of a soft rubber cuff connected to a rubber bulb that is used to inflate the cuff and a meter that registers the pressure of the cuff. The meter may be a dial or a glass column filled with mercury. Blood pressure is measured in millimeters of mercury (mm Hg) because the first instrument used to measure it was a mercury column. When a sphygmomanometer is used, a person sits with legs uncrossed and back supported. An arm is bared (if a sleeve is rolled up, caution is needed to ensure that it is not tight around the arm), bent, and resting on a table, so that the arm is about the same level as the heart. The cuff is wrapped around the arm. Using a cuff that is proportional to the size of the arm is important. If the cuff is too small, the blood pressure reading will be too high. If the cuff is too large, the reading will be too low. Listening with a stethoscope placed over the artery below the cuff, a health care practitioner inflates the cuff by squeezing the bulb until the cuff compresses the artery tightly enough to temporarily stop blood flow, usually to a pressure that is about 30 mm Hg higher than the person's usual systolic pressure (the pressure exerted when the heart beats). Then the cuff is gradually deflated. The pressure at which the practitioner first hears a pulse in the artery is the systolic pressure. The cuff continues to be deflated, and at some point, the sound of blood flowing stops. The pressure at this point is the diastolic pressure (the pressure exerted when the heart relaxes, between beats). Instruments to measure blood pressure are available for home use by people who have high blood pressure. |
Doctors also take a medical historyrisk factors
A thorough physical examination and standard blood and urine tests are done. Tests to evaluate kidney function and to check for high cholesterol are also done. Other tests may be done to check for specific disorders based on information from the history and physical examination.
Prevention of High Blood Pressure in Children
Weight reduction
Exercise
Reducing salt (sodium) intake
Obesity (determined by BMI), lack of physical activity, and a diet high in salt and/or calories are risk factors for high blood pressure (and for coronary artery disease). That is, these factors can contribute to or cause high blood pressure. Thus, modifying them can help prevent high blood pressure.
More and more children are becoming overweight or obese. One reason is that children are spending a lot of time in front of a screen. Experts estimate the following average number of hours spent in front of a screen:
Children 8 to 10 years old: 6 hours per day
Children 11 to 14: 9 hours per day
Children 15 to 18: 7½ hours per day
These averages include only the time spent in front of a screen for entertainment. They do not include the time spent using a computer at school for educational purposes or at home for homework. This amount of screen time comes at the expense of exercise and thus contributes to overweight and obesity.
When that much time is spent looking at a screen, there is less time to be physically active. Experts recommend
For children who are 6 to 17 years old: 30 to 60 minutes of moderate to vigorous physical activity each day or at least 3 to 5 days per week
For children under 6 years old: Physical activity throughout the day
Sodium increases blood pressure. When people consume too much salt (sodium), the body retains more fluid, leading to increased blood pressure. In the United States, most children consume more salt than is recommended. In the United States, children 6 to 18 years old are estimated to consume about 3,300 milligrams of sodium a day, not counting the salt that is added at the table. Experts recommend that children should eat less than 2,300 milligrams of sodium a day, and even less for children under 13 years of age.
Parents can help prevent high blood pressure in their children by
Providing healthful, lower-calorie foods such as fruits and vegetables at meals and as snacks
Providing foods that are low in salt
Making water always available (instead of sugary beverages, including energy drinks) and limiting fruit juice
Encouraging their children to be more physically active
Learning about what is considered overweight and obese
Helping their children maintain a healthy weight
Eating healthful foods and exercising each day themselves to be a role model for their children
Treatment of High Blood Pressure in Children
Weight loss, if needed
Changes in diet
Increased physical activity
Sometimes drug treatment
In children with high blood pressure, treatment may include increased physical activity, changes in diet to reduce salt and calorie consumption, weight loss, and sometimes drugs, depending on how severe the high blood pressure is.
Usually, treatment of high blood pressure begins with changes in lifestyle that can help lower blood pressure, such as diet and, if needed, weight loss. The number of calories is limited based on activity level, age, and sex, and salt consumption is limited. The DASH (Dietary Approaches to Stop Hypertension) diet can be helpful. This diet emphasizes eating lots of fruits and vegetables and using low-fat dairy products. It includes poultry, fish, whole grains, and nuts and limits consumption of red meats, sweets, and salt. The diet is also low in saturated fat and cholesterol.
Experts recommend
For children who are 6 to 17 years old: 30 to 60 minutes of moderate to vigorous physical activity each day or at least 3 to 5 days a week
For children under 6 years old: Physical activity throughout the day
If blood pressure goals have not been reached after about 6 months of lifestyle changes, treatment with drugs also may be needed in some children.
Children typically are referred to a specialist if their doctor requires help with prescribing drug therapy or if children have either of the following:
Stage 1 hypertension especially with symptoms, organ damage, diabetes, or a kidney disorder
Stage 2 (severe) hypertension
Drug treatment of high blood pressure in children
Immediate drug treatment (plus lifestyle changes) is typically started if any of the following apply:
High blood pressure, regardless of severity, causes symptoms.
Stage 1 hypertension causes organ dysfunction or damage.
Stage 2 hypertension is present.
Children have chronic kidney disease, diabetes, or heart disease regardless of the stage of high blood pressure.
Children who have milder forms of high blood pressure that are not controlled after about 6 months of lifestyle changes will need drug treatment.
Drugs that are used in the treatment of high blood pressure are called antihypertensive drugs. Treatment is most effective when the parents, child, and doctor communicate well and discuss the drug treatment program, including possible side effects. Any antihypertensive drug can have side effects, so parents should be alert for them. If side effects develop, parents or the child should tell the doctor, who can adjust the dose or substitute another drug.
Doctors typically start antihypertensive drugs, given by mouth, at a low dose and increase the dose as needed to lower blood pressure until the maximum dose of the drug is reached or side effects occur. If blood pressure is still too high, doctors may give children a second drug or switch drugs.
There are many types of antihypertensive drugs. Categories include
The different types of antihypertensive drugs work in different ways, so there are many options for treatment. It is not unusual for someone who has high blood pressure to be prescribed more than one of these drugs.
For a more detailed discussion of these types of drugs, see Drug Treatment of High Blood Pressure in Children.
More Information
The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.
U.S. Department of Agriculture and U.S. Department of Health and Human Services: 2020–2025 Dietary Guidelines for Americans
