Hypertension

What is hypertension?

Hypertension means “high blood pressure.” This refers to how hard the blood is pushing against the walls of the artery through which it flows—not how quickly it flows. In hypertension, the level of pressure is higher than normal.

How is blood pressure measured?

Blood pressure is measured in millimeters of mercury (mm Hg). A typical normal blood pressure in an adult is 120/80 mm Hg, or "120 over 80." The top number refers to the pressure when the heart is pushing blood out through the arteries (systolic). The bottom number refers to the pressure when the heart is at rest—“between beats” (diastolic).

It’s easy to tell whether an adult has hypertension, because there’s a standard set of measurements:

• Normal blood pressure—systolic < 120 mmHg and diastolic < 80 mm Hg
• Pre-hypertension—systolic 120-139 mmHg or diastolic 80-89 mmHg
• Stage 1 hypertension—systolic 140-159 mmHg or diastolic 90-99 mmHg
• Stage 2 hypertension—systolic ≥160 or diastolic ≥100 mmHg

But it’s harder with children. That’s because there are no universal cut-offs as there are for adults; instead, whether a child has hypertension depends on how his blood pressure compares to his peers (determined by gender, height, and age).

• Pre-hypertension—90^th to 95^th percentile
• Stage 1 hypertension—95^th – 99^th (plus 5 mm mercury)
• Stage 2 hypertension—anything higher than 99^th plus 5 mm mercury

How common is hypertension in children?

Hypertension is becoming increasingly common in children and adolescents. A recent study that looked at 15,000 adolescents found that nearly one in five had hypertension. And there’s reason to believe that hypertension is vastly underdiagnosed in children, since:

• it can be difficult to measure in infants and young children
• it’s sometimes challenging to identify
• it’s often thought of as not something that really affects kids

The rise in the number of children with primary hypertension in the United States is thought to correlate with the rise of obesity.

What complications are associated with hypertension?

While kids with hypertension are unlikely to have heart attacks and strokes, it still has significant risks. Hypertension causes changes in the structures of the blood vessels and heart. Since hypertension in children has historically been understudied, there isn’t a lot of data about exactly what these changes mean. But we do know that in adults, hypertension increases the chance of complications in the heart, blood vessels, and kidneys. There’s also compelling evidence that some of these changes are seen in children with high blood pressure.

These changes affect:

Blood vessels—high blood pressure can damage blood vessels throughout the body, which makes it harder for organs to work efficiently.

Kidneys—if the blood vessels in the kidneys are damaged, they may stop removing waste and extra fluid from the body. This extra fluid can raise blood pressure even more.

Other organs—if left untreated, hypertension makes it harder for blood to reach many different parts of the body, including the eyes and the brain, and can lead to blindness and strokes.

Can primary hypertension be prevented?

Pediatricians are making great efforts to prevent obesity and stem the tide of problems that accompany it. We believe that promoting healthy lifestyle choices will help combat this trend and will go a long way towards preventing primary hypertension in children (and keep adults healthier, too).

Some things are being done—nutritional information is being made more readily available, there’s one push to provide healthy options in schools and another to remove soft drinks from them—but still, it often comes down to families making the right decisions. We are dedicated to educating families to assist with appropriate dietary and activity choices to improve overall health and reduce the risk of hypertension.

What is “white coat hypertension”?

“White coat hypertension” is when a child’s blood pressure readings are high at the doctor’s office (mostly because she’s anxious, which can cause blood pressure to rise), but normal outside of the office (for example at home or at school).

This is pretty common in kids. By some estimations, between 30 and 40 percent of kids who have high blood pressure in the office actually have white-coat hypertension.

White coat hypertension is still a risk. Everyone’s blood pressure changes from time to time—it’s lower when you’re asleep, for example­­­­­—but if a child’s blood pressure continually rises when she’s anxious (such as before a test), it can be sign of high blood pressure at other times and potentially cause the same kinds of damage that standard hypertension causes.

White coat hypertension is diagnosed by taking the child’s blood pressure outside of the doctor’s office. This can be done in different ways:

• Some parents feel comfortable doing it at home.
• Sometimes we make arrangements for a school nurse to check the child’s blood pressure.
• Your child’s doctor might recommend that she wear an ambulatory blood pressure monitoring device—a blood pressure cuff attached to a small device that sits on her belt , and measures her blood pressure at regular intervals over the course of 24 hours. This device is about the size of a deck of cards and is usually tolerated very well.

If your child is diagnosed with white coat hypertension, her doctor may still want to follow her, since some children with white coat hypertension will develop actual hypertension in the future.

Causes of hypertension in children

1. Primary hypertension

Primary hypertension means that the hypertension does not seem to be caused by some other underlyng medical condition. Many doctors think that the incidence of childhood or adolescent hypertension has been rising along with the obesity epidemic. The majority of teens and children over age 6 with hypertension have a family history of hypertension and/or are overweight.

2. Secondary hypertension

Secondary hypertension is caused by a known underlying medical condition. Of these, about

• 80 percent of children have some kind of kidney disease or blood vessel abnormalities
• 5 percent have an endocrinological disorder
• 2 to 5 percent have heart disease

Hypertension in infants with hypertension almost always has a secondary cause. In addition, premature infants have a higher incidence of hypertension.

Among kids with hypertension, especially those who are very young, secondary hypertension is more common than primary hypertension. But among children who are older than 6 to 8 years old, the ratio of primary to secondary hypertension is approaching 50/50.

Signs and symptoms of hypertension

Often, kids and teens with pre-hypertension or stage 1 hypertension won’t show any symptoms at all. If your child has stage 2 hypertension, she might experience one or more of the following symptoms:

• headaches
• loss of vision
• double-vision
• chest pain
• abdominal pain
• breathing problems

An infant with stage 2 hypertension may seem irritable, not be feeding properly, or vomiting. Sometimes these infants are diagnosed with “failure to thrive.”

Frequently Asked Questions (FAQ) about Hypertension

Q: If left untreated, does hypertension get worse?

A: It’s hard to say. Researchers are starting to see that kids and adolescents with pre-hypertension are more likely to develop stage 1 hypertension, but we don’t know if  or when stage 1 hypertension will progress to stage 2.

Q: Can hypertension be cured?

A: In some cases, secondary hypertension can be “fixed.” For example, if:

• it’s caused by a narrowing in a blood vessel that the doctors are able to widen
• it’s caused by a rare endocrine tumor that doctors are able to treat successfully

There are also cases in which hypertension might be transient; for example, if it’s caused by a temporary inflammation of the filters in the kidney.

Even when hypertension can’t be “fixed,” it can almost always be well-controlled, with diet and exercise and/or medication.

Q: If my child is being treated for hypertension, what should I watch out for?

A: Keep an eye out for:

• chest pains
• severe headaches that don’t seem to respond to at-home treatment
• changes in vision
• nausea
• swelling of hands and feet
• shortness of breath with limited exertion
• changes in her urine (such as lack of urine production, urine that is brown or tea-colored)

Call your child’s doctor if she experiences any of these symptoms.

Q: Will my child need to go on medication?

A: Only a fraction of kids with hypertension require medication. Frequently, it’s treated with diet and exercise modification first. And if the child is overweight, every kilogram (around 2 pounds) of weight she loses, her blood pressure could bring her blood pressure down by about a point.

Q: Will my child have hypertension as an adult?

A: While children with hypertension are more likely to have it as adults, it’s not necessarily always the case. This depends on factors including the cause of the hypertension and how it responds to treatment.

Q: What is the most common treatment?

A: For children with pre-hypertension or stage 1 hypertension, changing to a more healthful diet and exercising more is often enough to manage the hypertension. For children with more severe hypertension, medication is often necessary.

Q: If my child is taking medication for hypertension, will she have to take it for the rest of her life?

A: Not necessarily. If your child has primary hypertension, appropriate lifestyle modifications may allow for medications to be stopped. In addition, if a secondary cause is identified and successfully treated, medications may not be necessary.

Back to top.

In diagnosing hypertension at Boston Children's Hospital, we look at two things: whether a child actually has hypertension, and if so, what could be causing it.

Does the child have hypertension?

Two steps are required to determine whether a child truly has hypertension:

1. There are very clear guidelines about how to measure a child’s blood pressure, but sometimes they aren’t followed, and the results can be misleading. These guidelines include making sure that:

• the cuff that clinicians use to measure blood pressure is the right size for the child
• the cuff is placed in the proper position
• the child is seated in the proper position
• the child is relaxed (hasn’t just run up four flights of stairs to the doctor’s office)

The doctor will then compare the numbers from the blood pressure reading to a chart blood pressure values, to see which percentile your child’s blood pressure falls into.

2. In order to be diagnosed with hypertension, there needs to be a pattern of elevated blood pressure. This pattern can be established in a few different ways:

• Blood pressure could be measured on three different doctor’s office visits. Depending on how high the child’s first blood pressure reading was, these visits may be separated by a week or less. The higher the blood pressure, the more closely together the visits will be.
• A parent may feel comfortable taking his or her child’s blood pressure at home.
• The child’s school nurse might take the blood pressure.
• Your child might be asked to wear an ambulatory blood pressure monitor.

What could be causing the hypertension?

The next step is to look for any damage to your child’s organs that might have already occurred, and find out what is causing the high blood pressure.

First, her doctors will run screening tests, including:

• urine tests
• blood tests

Based on the results of those tests, other tests may be ordered, including:

• kidney ultrasound
• echocardiogram
• other diagnostic imaging
• eye exam

How are infants diagnosed with hypertension?

It can be challenging to diagnose hypertension in infants because most pediatricians don’t start checking blood pressure until a child is two years old. But if an infant has risk factors for hypertension, her doctors will monitor her blood pressure. These factors include:

• being born prematurely
• having a history of urinary tract infection or other kidney problem
• having a history of heart disease
• being small for gestational age/weight at birth

Hypertension in an infant has a much higher probability of being caused by an underlying condition, so doctors are very thorough when looking for signs of one. In addition to the diseases and conditions they’d look for in an older child, they’ll also look for blood vessel malformations of the aorta and kidney.

After we complete all necessary tests, our experts meet to review and discuss what they have learned about your child's condition. Then we will meet with you and your family to discuss the results and outline the best treatment options.

How do we treat hypertension?

Learning that your child has high blood pressure can certainly be distressing, but it's almost always easily managed.

Most primary hypertension can be treated with changes in diet and exercise habits, and if necessary, there are medications that can help, too.

The good news is not all children require medication for high blood pressure. Many will improve with diet and exercise.

Your child's treatment plan may depend on:

• whether the hypertension is primary or secondary (if secondary, treating the underlying condition may help resolve the hypertension)
• the severity of blood pressure elevation

Pre-hypertension

Sometimes our doctors monitor children with pre-hypertension, seeing them once every six months or so. We'll provide counseling regarding healthy lifestyle choices to prevent progression to stage 1 or 2 hypertension.

Stage 1 hypertension

If your child has high blood pressure but is showing no symptoms, we may ask her to try three to six months of lifestyle modification (changes in diet and exercise). We may start by seeing her every three months, and if her hypertension is improving, gradually decrease the frequency of appointments depending on how things are going.

Stage 2 hypertension

We see children with stage 2 hypertension more frequently, although exactly how frequently depends very much on the individual child. If the hypertension is severe, we may start her on medication early, to get the hypertension under control, and follow up every two weeks if necessary. Once her blood pressure is brought under control, her appointments will be less frequent.

Diet and exercise

We encourage realistic and progress-oriented goals when it comes to making lifestyle changes like diet and exercise. Typically, we recommend a gradual increase in physical activity, with emphasis on aerobic exercise (exercise that raises your pulse and helps your heart relax). We also encourage a diet rich in fresh fruits, fresh vegetables and whole grains, and limited in sodium, fat and sugar-sweetened beverages.

Since excess salt can raise blood pressure, our dieticians often recommend that families focus on the amount of sodium they eat. Around 75 percent of excess salt comes from packaged and canned foods (and not from the salt shaker), simply switching from canned vegetables to frozen vegetables can help lower blood pressure.

We encourage aerobic exercise for almost all children with hypertension. Rarely, a child with severe hypertension may be restricted from specific activities. In these cases, restrictions may be lifted once the hypertension is adequately treated.

We emphasize the importance of family-wide commitment toward a healthy style. Since 90 percent of us will have hypertension by the time we're 80 years old just from normal aging, diet and lifestyle changes are important for everyone—not just children with high blood pressure.

Medication

Medication may be necessary to treat hypertension. Whether your child is prescribed medication for hypertension depends on a few things:

• How high is her blood pressure?
• How long has it been present?
• Does it appear to be causing problems with her organs?
• Has it responded to diet and exercise modification? If so, how well?

Sometimes, we treat a child with medication and changes in diet and exercise, in the hope that if she loses weight, we can take her off of the medicine. Once medication is started, they're monitored closely to determine if dose increases or decreases are required or if medication side effects occur.

Hypertension is a very wide-ranging disease. It can be difficult to predict what medicines a child will respond to, and how many medicines it will take to control a given child's blood pressure. If a child has chronic kidney disease or primary hypertension (in which case the doctor may not know what is causing the hypertension), it might take more than one medication to bring the blood pressure into a normal range for that child.

Remember–if your child's hypertension can't be controlled with diet and exercise alone, it's not a failure. It's important to keep exercising and eating healthfully. This is because exercise and healthy eating help to prevent a variety of other health problems.

If my child takes medication for hypertension, will she have to take it for the rest of her life?

Not necessarily. If there's an underlying cause for the hypertension and its treatment is successful, she may not have to stay on medication. If your child has primary hypertension, increased exercise and appropriate changes to her diet may allow her to be taken off of medication.

How do you treat infants with hypertension?

Infants may be treated with doses of liquid medication or with medicines given through an IV if they are hospitalized.

Premature infants sometimes have hypertension that starts right in the neonatal period or in the first couple months of life. We generally start these infants on medication to stabilize their hypertension. Some of these infants grow out of their hypertension and are able to stop medication when they are 1 to 2 years old.

What's the long-term outlook for my child?

Every child is different, but in general, the outlook for kids with hypertension is quite good. It can almost always be well-managed with medications and/or changes in diet and exercise.

Boston Children's Hospital is home to the world’s largest research program at a pediatric institution, and we’re known for pioneering new treatments. A large part of our success comes from our commitment to research—and to advancing the frontiers of what’s possible through our innovative approach.

Our Hypertension Program is in the process of building collaborations and partnerships with children’s hospitals and other institutions around the country, trying to understand pediatric cardiovascular risk factors such as hypertension and how they link up to adult arteriosclerotic heart disease.

Our clinicians are also involved with:

• adapting techniques used to research cardiovascular risk in adults for children
• integrating blood pressure measurement data into Children’s electronic records
• retraining clinical assistants, nurses and other staff members about how to measure kids’ blood pressure appropriately, compare the readings to the appropriate norms and encourage the kids to have follow-up and treatment if necessary
• developing a protocol to ensure that high blood pressure in children is cared for in the same way across various departments within Boston Children’s