Hypertension in Children
Dr. Alexandru R. Constantinescu is a pediatric nephrologist, practicing in Hollywood, Florida. Dr. Constantinescu is specialized in the health care of children with kidney diseases and hypertension. As a pediatric nephrologist, Dr. Constantinescu diagnoses and treats children with protein or blood in the urine, hypertension,... more
Alex R Constantinescu, MD
Chief, Pediatric Nephrology and Hypertension
Joe DiMaggio Children’s Hospital, Hollywood, FL
About 4% of children 12-19 years of age have hypertension, although 10% have elevated blood pressure (previously called pre-hypertension state). The incidence has increased around the world and it is appreciated to be a risk factor of hypertension later in life (1). As such, one in three adults has hypertension in the U.S., and unfortunately, an additional 20% are unaware of their high blood pressure (2).
What is hypertension?
The blood pressure is the pressure applied by the blood, pumped by the heart, on the vessel walls. It can be measured directly (inside the vessel with an arterial line) or indirectly (with the blood pressure cuff). Higher than normal readings are considered hypertension in certain circumstances free of environmental influences. In living organisms, the vessels are elastic and react to various stimuli - external (for example, ambient temperature) or internal (such as hormones). The tissue perfusion is needed for oxygenation and has to be maintained by certain compensatory mechanisms. For instance, in cold temperatures, the vessels contract, raising the resistance that leads to higher blood pressure to bring oxygen to the tissues. In warm environments, states of fever, or after a strenuous exercise, the vessels dilate, patients sweat, and to prevent a drop in blood pressure, the heart starts beating faster to compensate and maintain adequate tissue perfusion. Various hormones regulate the blood pressure, and if deficient can lead to low blood pressure, or if in excess, can lead to high blood pressure. If blood pressure is persistently high for at least two weeks, the patient has hypertension. Though genetic predisposition plays a role, some factors clearly influence the development of hypertension, independent of gene mutations.
How does a pediatrician suspect hypertension in a child?
The American Academy of Pediatrics published in 2017 the Clinical Practice Guideline for screening and management of high blood pressure in children and adolescents (3). To determine if a child has hypertension, the pediatricians use appropriate cuffs for the size of the arm, being aware of the environment, prior or current medications, as well as family history. Tables indicate the upper limit of normal for blood pressure readings based on gender, height and age. If the elevated blood pressure persists over a period of two weeks, with at least three readings being obtained, the diagnosis of hypertension is established, and further workup is needed to determine the cause.
The initial testing is non-invasive, being comprised of urine and blood tests, ultrasound of both kidneys and heart. A blood pressure monitor can be placed in children at least 5 years of age, to determine the blood pressure load over a 24-48 hour period, a better assessment when compared to office or home blood pressure readings. In special cases, further testing is recommended depending on the initial results, sometimes with invasive testing like biopsies and angiograms.
Is childhood hypertension different from hypertension in adults?
The majority of adults have what is called “essential” hypertension – in other words, no identifiable cause was found. This is in contrast to children, whose hypertension is mostly “secondary” to renal, cardiac or endocrine disorders, and can also be induced by certain medications. The kidneys can be the reason as well as the target of hypertension since they play an important role in blood pressure control. Patients with chronic kidney disease, in various stages of kidney dysfunction, have a high risk of developing hypertension. Therefore, it is important to diagnose renal disease early and monitor it regularly, with the help of the pediatrician and the pediatric nephrologist. The heart can suffer from persistent hypertension and an ultrasound of the heart, called an echocardiogram, can identify the effect of hypertension as well as possible causes. Medications such as steroids for the treatment of various diseases can lead to hypertension, and a few endocrine disorders can also cause elevated blood pressure. Their identification requires detailed work-up.
What is the therapy for hypertension in children?
One has to think of therapy for hypertension with a first step being non-pharmacologic (without medications) and, if insufficient to normalize the blood pressure for age, gender and height, add a second step with anti-hypertensive medications. The non-pharmacological approach implies a lower sodium diet (discuss with the doctor or the dietician, since the daily allowance varies with age and weight), weight management (avoid excess and/or promote weight loss), and physical activity (mostly aerobic). The second step, added to, not replacing the first, consists of various classes of medications which are prescribed based on the patient’s characteristics and the specific cause of hypertension. The younger the children, the more likely they are being started on both drug therapy and non-pharmacologic step. A special note of caution to mention is related to the need to discuss with the physicians and monitor the side effects of each of these drugs, prevent the hypotensive episodes (sudden drop in blood pressure) as well as end-organ damage – eyes, kidneys, brain and cardio-vascular system suffering from uncontrolled hypertension.
In summary, hypertension in children is being diagnosed more frequently, and it has been demonstrated that it can lead to adult hypertension. Therefore, it needs to be recognized, worked-up to find a cause and treat accordingly, under the supervision of the pediatrician and the hypertension specialists.
Suggested readings:
- Song P et al. Global prevalence of hypertension in children. A systematic review and meta-analysis. JAMA Pediatr2019;173:1154-1163. doi:10.1001/jamapediatrics.2019.3310
- https://www.cdc.gov/bloodpressure/
- Flynn JT et al. Clinical practice guideline for screening and management of high blood pressure in children and adolescents. Pediatrics 2017;140:e20171904. https://doi.org/10.1542/peds.2017-1904
