Definition and diagnosis of hypertension in children and adolescents

INTRODUCTION — There is increasing evidence that adult hypertension has its antecedents during childhood as childhood blood pressure (BP) predicts adult BP [1-3]. Hypertension in childhood and adolescence may contribute to premature atherosclerosis and the early development of cardiovascular disease. As a result, identifying and successfully treating children with hypertension may have an important impact on long-term outcomes of cardiovascular disease. (See "Overview of risk factors for development of atherosclerosis and early cardiovascular disease in childhood" and "Nonemergent treatment of hypertension in children and adolescents", section on 'Rationale for intervention'.)

The definition and diagnosis of hypertension in children will be reviewed here. Related content can be found in the following topic reviews:

●(See "Epidemiology, risk factors, and etiology of hypertension in children and adolescents".)

●(See "Evaluation of hypertension in children and adolescents".)

●(See "Nonemergent treatment of hypertension in children and adolescents".)

●(See "Etiology, clinical features, and diagnosis of neonatal hypertension".)

DEFINITIONS

United States — The American Academy of Pediatrics (AAP) and American Heart Association define the following blood pressure (BP) categories for children and adolescents (table 1) [4]:

●Children 1 to <13 years of age:

•Normal BP – Both systolic BP (SBP) and diastolic BP (DBP) <90^th percentile.

•Elevated BP (previously referred to as prehypertension) – SBP and/or DBP ≥90^th percentile but <95^th percentile, or 120/80 mmHg to <95^th percentile (whichever is lower). Elevated BP is predictive of hypertension [5].

•Stage 1 hypertension – SBP and/or DBP ≥95^th to <95^th percentile + 12 mmHg, or 130/80 to 139/89 mmHg (whichever is lower).

•Stage 2 hypertension – SBP and/or DBP ≥95^th percentile + 12 mmHg, or ≥140/90 mmHg (whichever is lower).

●Children ≥13 years of age:

•Normal BP – BP <120/80 mmHg.

•Elevated BP (previously referred to as prehypertension) – SBP between 120 and 129 mmHg with a DBP <80 mmHg.

•Stage 1 hypertension – BP between 130/80 to 139/89 mmHg.

•Stage 2 hypertension – BP ≥140/90 mmHg.

High BP, including hypertension, is defined from normative distribution of BP data in healthy children that includes children from the National Health and Nutrition Examination Survey and other screening studies. This is in contrast with adult hypertension, which is primarily defined by clinical outcome data (ie, risk of cardiovascular disease and mortality) from large trials of antihypertensive therapy. However, these outcome measures cannot be applied to children, because cardiovascular events other than left ventricular hypertrophy do not typically occur in childhood. (See "Overview of hypertension in adults".)

Pediatric BP levels are interpreted based on sex, age, and height. In the 2017 AAP guidelines, normative tables (table 2 and table 3) were revised by using data only from normal-weight children. The revised tables excluded BP data from overweight and obese children (ie, children with body mass index ≥85^th percentile) that were previously included in normative BP databases. As a result, BP values are several mmHg lower than in similar tables in previously published normative values by the National High Blood Pressure Education Program Working Group [4,6].

Of note, the definitions for adolescents are aligned with adult guidelines for the detection of elevated BP.

Other countries — In other countries, several studies have collected data to define normative BP for their children [7-9].

●Great Britain – In Great Britain, reference-range BP percentiles for children and young adults between 4 and 23 years of age were based on demographic data obtained from seven national surveys that recorded three BP measurements using an oscillometric device [9]. High-normal BP for age was defined as SBP or DBP >91^st to ≤98^th percentile for age, and high BP was defined as >98^th percentile for age.

●Europe – For children <16 years, the European Society of Hypertension (ESH) defined high-normal BP as ≥90^th to <95^th percentile for age and hypertension as ≥95^th percentile for age, using normative data from the United States [10]. For individuals 16 years or older, the ESH guidelines recommend using the adult thresholds of ≥130/85 mmHg to define high-normal BP and ≥140/90 to define hypertension [11]. The diagnosis of hypertension is based on measurements on two separate visits. (See "Overview of hypertension in adults", section on 'Hypertension'.)

●China – National BP references based on age, sex, and height have been developed based on data from children between 7 to 17 years of age who participated in the 2010 Chinese National Survey on Students' Constitution and Health [12]. BP percentiles were established and compared with United States and previous Chinese references.

●International – International BP reference values for children between 6 and 19 years of age have been developed using data from nationally represented cross-sectional surveys from seven countries [13]. However, in addition to the age restriction at or above six years, variations in population factors (eg, diet, activity, and perhaps genetic predisposition) and the lack of outcome data limit the general clinical applicability of these values [14].

DIAGNOSIS — In the United States, the diagnosis of persistent childhood hypertension is made when serial blood pressure (BP) values on three separate visits are (table 1) [4,15]:

●Children <13 years – BP ≥95^th percentile for age, sex, and height, or ≥130/80 mmHg (whichever is lower) (table 2 and table 3)

●Children ≥13 years – BP ≥130/80

Slightly different diagnostic criteria are used in other countries. (See 'Other countries' above.)

The diagnosis of hypertension depends on serial accurate measurements of BP throughout childhood using a standardized procedure and equipment. (See 'Measurement of blood pressure' below.)

SCREENING OF BLOOD PRESSURE

Frequency of screening — In our practice, we follow the recommendations laid out by 2017 American Academy of Pediatrics (AAP) guidelines for high blood pressure (BP) in children and adolescents, which are endorsed by the American Heart Association and consistent with guidelines from the National Heart, Lung, and Blood Institute, and the European Society of Hypertension (ESH) [4,10,16]:

●For children ≥3 years of age without risk factors or conditions associated with hypertension, measure BP during annual health supervision visits.

●For children of any age with risk factors for hypertension, measure BP at every health care encounter. Risk factors for hypertension are outlined in the tables (age <3 years (table 4); age ≥3 years (table 5)).

Children with systolic BP (SBP) or diastolic BP (DBP) that exceeds screening thresholds for age and sex (table 6) require further evaluation, starting with repeat BP measurement.

Tracking — Tracking refers to the pattern of repeated BP measurements over time. The clinical importance of tracking in children with annual BP over the age of three years is related to the ability to predict BP status later in childhood and adulthood. Children, especially adolescents, who are hypertensive are more likely to remain hypertensive throughout childhood and as adults, particularly in the presence of a family history of hypertension, increased body weight, or increased left ventricular mass [17-24]. (See "Epidemiology, risk factors, and etiology of hypertension in children and adolescents".)

However, there are data that, in some children, hypertension or elevated BP will return to normal levels. This was illustrated in a primary care study based on data from the electronic medical records of almost 400,000 children that reported subsequent normalization of BP for most children who met criteria for either hypertension or elevated BP with ≥3 BP measurements recorded over 36 months [25]. Over a second concurrent 36-month period, no abnormal BP levels of the ≥3 BP measurements were recorded of 50 percent of children previously diagnosed during the first time period with hypertension (933 of 1881) or 70 percent of those diagnosed with elevated BP (1492 of 2144). Of note, a minority of patients had significant increases of BP, with 12 percent of children with elevated BP progressing to a higher BP category and 5 percent of children with stage 1 hypertension progressing to stage 2 hypertension in the second 36 months. Also, only one-half of the 7775 children with abnormally elevated BP in the first 36-month period had ≥3 BP measurements recorded during the second 36-month period. Limitations of this study included the small number of children in the entire cohort with longitudinal BP measurements necessary for study inclusion and those due to data extraction from the electronic medical record, such as inability to determine if measurements were done appropriately and whether interventions (eg, lifestyle changes) were implemented. Nevertheless, these results highlighted normalization of BP for many children with abnormally high BP and the need to ensure that these children have adequate follow-up with subsequent BP measurements. Further studies are needed to verify these results, and, if findings are consistent regarding subsequent normalization of BP, this raises the possibility that criteria may need to be modified to include longer follow-up BP monitoring before diagnosing a child with hypertension.

Societal and governmental recommendations — In 2020, the United States Preventive Services Task Force reaffirmed their previous conclusion based on a systematic reevaluation of the available evidence that there was inadequate evidence to support for or against BP screening in asymptomatic children and adolescents [26]. The task force recommendation is based on their assessment of inadequate evidence regarding accuracy of screening and the benefits of interventions (nonpharmacologic and pharmacologic measures) in long-term reduction of BP or effectiveness in reducing adverse health outcomes associated with high BP in adults and no direct evidence of benefit that pediatric screening reduces adverse health outcomes. In addition, there is insufficient evidence regarding whether there is harm associated with either early detection of high BP or interventions to treat high BP.

In contrast, the AAP; American Heart Association; National Heart, Lung, and Blood Institute; and ESH recommend BP screening in children and adolescents [4,10,16,27]. These recommendations are based on the direct evidence of BP tracking from childhood to adulthood (see 'Tracking' above), indirect evidence that elevated BP in children is associated with subclinical cardiovascular disease (including left ventricular mass and carotid intima-media thickening), and autopsies in adolescents and young adults demonstrating a relationship between high BP and atherosclerotic lesions (see "Nonemergent treatment of hypertension in children and adolescents", section on 'Cardiovascular disease') and also because BP screening can identify children who would be benefit from counseling that promotes health lifestyles [28,29].

MEASUREMENT OF BLOOD PRESSURE — The diagnosis of hypertension depends on accurate blood pressure (BP) measurement. If a high BP measurement is obtained by an oscillometric device, confirmation by ausculatory measurement is required for accuracy.

The variability of BP values due to procedural differences in BP measurement was illustrated in a comparison of normal BP readings reported by 10 different investigators in which the BP values differed by as much as 20 mmHg [30]. Confounding factors included cuff size, technique used (ie, patient position and choice of fourth or fifth Korotkoff sound to determine diastolic BP [DBP]), number of measurements made, and/or type of instruments used. (See 'Technique of blood pressure measurement' below.)

Cuff size and placement — A variety of different cuff sizes are available, including adult, large adult, and thigh cuffs. The correct choice of cuff is important for accurate BP measurement.

●Correct size – The cuff size should have a bladder width that is approximately 40 percent of the circumference of the upper arm, measured midway between the olecranon and the acromion (figure 1). The clinician should measure arm circumference and use the appropriately sized cuff as printed inside the device. Exact sizes may differ by manufacturer. The length of the cuff bladder should encircle 80 to 100 percent of the circumference of the upper arm midway between the olecranon and the acromion [4]. The bladder width to length should be at least 1:2.

●Inaccurate BP measurements – BP measurement may be inaccurate if an inappropriately small or large cuff is used.

•Inappropriately small cuff – If too small a cuff is used, it will overestimate the systolic BP (SBP). This is because the pressure generated by inflating the cuff may not be fully transmitted to the brachial artery such that the pressure in the cuff may be considerably higher than the intraarterial pressure.

•Inappropriately large cuff – Too wide a cuff may produce lower readings than the actual intraarterial pressure.

Auscultation — The normative data was obtained by using a mercury sphygmomanometer [4], which is the gold standard for indirect BP measurement. However, mercury sphygmomanometers are no longer available, because of the potential environmental risk of mercury poisoning. Aneroid sphygmomanometers are an appropriate substitute for mercury-containing devices and have been shown to be accurate if regularly calibrated [31].

Technique of blood pressure measurement — The following steps are recommended to accurately measure BP by auscultation and compare values with normative data [4,10,15].

●The BP should be measured after three to five minutes of rest in a quiet environment. The child should be seated with their back and feet in a supported position. In infants, BP is measured in a supine position.

●Measure BP when the heart rate is normal and steady to minimize the likelihood of obtaining falsely elevated readings. Because anxiety acutely raises both heart rate and BP, the most reproducible readings are obtained when the pulse rate is both steady and within the normal range.

●BP is measured preferentially in the right arm for consistency and comparison with standard tables. In addition, the possibility of coarctation of the aorta would lead to falsely low BP readings in the left arm.

●BP is measured by auscultation using the correct size and placement of the BP cuff and by placing the bell of the stethoscope over the brachial artery pulse in the cubital fossa (figure 1 and figure 2). BP should be taken with the patient's right arm supported at the level of the heart. Allowing the arm to hang below the heart will elevate BP levels by the added hydrostatic pressure induced by gravity (as much as 10 to 12 mmHg in adults) [32]. The sphygmomanometer should be visible but does not have to be at the level of the heart [33].

●The cuff should be inflated to 20 to 30 mmHg above the anticipated SBP and then deflated slowly at a rate of 2 to 3 mmHg per heartbeat. The SBP is equal to the pressure at which the brachial pulse (initial tapping sound) can first be heard by auscultation (Korotkoff phase I). As the cuff is deflated below the SBP, the pulse continues to be heard until there is abrupt muffling (Korotkoff phase IV) followed by disappearance of sound (Korotkoff phase V) [34]. The DBP is the pressure at which the sound disappears. (See 'Number of measurements' below.)

●Phase V is recommended for DBP determination in children [4]. In some children, Korotkoff sounds can be heard to 0 mmHg. If this occurs, BP measurement should be repeated with less pressure on the head of the stethoscope. If phase V is still very low, phase IV (muffling) should be recorded as the DBP with the added documentation noting the use of the phase IV to determine DBP.

●Wait until the needle reaches zero before inflating the cuff for the next reading.

Number of measurements — BP should be taken at least twice on each visit, with the measurements separated by one to two minutes to allow the release of trapped blood. If the second value is more than 5 mmHg different from the first, continued measurements should be made until a stable value is attained. The recorded value on the patient's chart should be the average of the last two measurements [35].

A new diagnosis of hypertension should not be made until the SBP and/or DBP measurement is above the hypertension threshold on multiple visits, as outlined above (see 'Diagnosis' above) [4,15]. Many children have substantial reductions in BP between the first and third visits [36-38]. The fall in BP with serial measurements is primarily because of two factors: an accommodation effect resulting from reduced anxiety over time and regression to the mean. (See 'Diagnosis' above.)

Oscillometric devices — Automated office devices measure mean arterial BP based on pressure oscillations of the brachial artery wall as the cuff is deflated. SBP and DBP measurements are calculated based on the mean BP. Manufacturers of oscillometric devices use different algorithms for these calculations.

Oscillometric devices are commonly used in practice because of their ease of use and decrease in observer bias [4,39,40]. They are particularly helpful when auscultation is difficult, like when screening infants and neonates, when in the intensive care setting when frequent BP measurement is needed, or when screening initial BP in a busy clinical setting [41]. In systematic reviews, SBP measurements obtained by oscillometric devices were higher compared with readings obtained by auscultation, with differences ranging from 1 to more than 10 points higher [40,42-44]. As a result, we concur with the American Academy of Pediatrics (AAP) recommendations that BP readings ≥90^th percentile obtained with an oscillometric device should be confirmed by auscultation [4].

Limitations of oscillometric devices include:

●There is a wide range of BP values when different devices are compared, with 30 percent of SBP measurements varying by more than 10 mmHg [45].

●Oscillometric devices require maintenance and repeated calibration. When routine maintenance is not followed, the accuracy of BP measurements may be affected.

Despite these limitations, the use of oscillometric devices as an initial BP screen is reasonable given how easily they can be used. However, caution should be used when interpreting BP results with these devices and ausculatory confirmation using an aneroid sphygmomanometer is required. This is especially important when oscillometric readings are high or in patients who are at risk for hypertension [4].

Our approach — In our institution, the following steps are used to screen for high BP and are in accordance with the 2017 AAP guidelines for high BP in children and adolescents [4,41] (see 'Technique of blood pressure measurement' above):

●An appropriate cuff size to the size of the child's upper arm is required for accurate measurement. (See 'Cuff size and placement' above.)

●To directly compare BP values with normative data, BP measurement is performed in the right arm after the patient has been resting comfortably for at least three minutes in a seated position in a quiet environment. (See 'Technique of blood pressure measurement' above.)

●An oscillometric device is generally used to screen initial BP measurement. However, if two to three BP measurements exceed the 90^th percentile by oscillometry, it is confirmed by an auscultatory measurement. (See 'Oscillometric devices' above and 'Technique of blood pressure measurement' above.)

●In the initial evaluation for hypertension, BP measurements are obtained in both upper and lower extremities to detect the possible presence of coarctation as the cause of hypertension. (See "Clinical manifestations and diagnosis of coarctation of the aorta".)

●At each visit, at least two BP measurements are obtained and spaced one or two minutes apart. The values should be less than 5 mmHg apart, and continued measurements are made until a stable value is attained. The recorded value on the patient's chart is the average of the last two measurements. (See 'Number of measurements' above.)

FOLLOW-UP — The timing of repeat blood pressure (BP) measurements depends on the initial level of increased BP (table 1) and if there are symptoms associated with hypertension (table 7) [4,46]. Follow-up BPs should be measured by auscultation; both upper and lower extremity BPs should be measured to detect coarctation of the aorta on at least one occasion (if not previously done).

●Elevated BP – For children with elevated BP documented by auscultatory measurements, nonpharmacologic therapy (ie, lifestyle changes) is recommended and BP should be rechecked by auscultation in six months.

•If BP remains elevated after six months, reinforce lifestyle counseling and recheck auscultated BP in six months.

•If BP continues at the elevated BP level after 12 months (eg, after three auscultatory measurements), ambulatory BP monitoring (ABPM) should be considered and diagnostic evaluation should be considered if appropriate. Consider subspecialty referral (ie, nephrology or cardiology). If ABPM is not available, home BP readings with appropriate training and BP cuff may be considered to help with further management decisions. (See "Evaluation of hypertension in children and adolescents" and "Nonemergent treatment of hypertension in children and adolescents", section on 'Nonpharmacologic therapy'.)

If BP normalizes at any point, return to annual BP screening at health supervisory care visits.

●Stage 1 hypertension – Provide recommendations for nonpharmacologic measures, and recheck within one to two weeks (or sooner if the patient is symptomatic). If BP remains elevated, recheck BP in three months by auscultation. If BP remains at the stage 1 level, ABPM should be ordered (if available) and diagnostic evaluation should be considered if appropriate. Consider subspecialty referral (ie, nephrology or cardiology). (See "Evaluation of hypertension in children and adolescents".)

●Stage 2 hypertension – Children with stage 2 hypertension require prompt evaluation and, possibly, immediate pharmacologic treatment.

•If the patient is symptomatic, the child should be referred for immediate care (eg, emergency department). (See "Initial management of hypertensive emergencies and urgencies in children".)

•If the patient is not symptomatic, review and reinforce lifestyle recommendations and repeat the BP measurement within one week. Alternatively, the patient could be referred to a subspecialist with expertise in the evaluation and management of elevated pediatric BP within one week. If, at the next visit, the BP is still at the stage 2 level, diagnostic evaluation including ABPM and treatment by a specialist should be considered. (See "Evaluation of hypertension in children and adolescents".)

As noted previously, these categories do not apply to an acute elevation of BP, where the magnitude and rate of increase above baseline determine whether there are symptoms and the risk of serious morbidity and, at times, mortality.

AMBULATORY BLOOD PRESSURE MEASUREMENTS — Blood pressure (BP) changes continually in response to physiologic and environmental stimuli and is higher when individuals are active and/or ambulatory versus when they are at rest. Ambulatory BP monitoring (ABPM) is used increasingly because of its ability to records numerous BP readings during a 24-hour time period while the child is engaged in their normal activities, including sleep [4,27].

●Patient selection – We suggest using ABPM to confirm the diagnosis of hypertension in children, where available, as recommended in guidelines from the American Heart Association and the American Academy of Pediatrics (AAP) [4,27]. ABPM is particularly valuable to identify children whose clinic BP is spuriously elevated due to anxiety (eg, white coat hypertension) or those with masked hypertension, in which home BP is higher than office BP measurements. It also provides information about circadian BP patterns that can be useful for evaluating children with chronic kidney disease, diabetes, autonomic dysfunction, or episodic hypertension and the BP response to therapeutic intervention. Considerations and selection of patients for ABPM are discussed elsewhere. (See "Ambulatory blood pressure monitoring in children".)

●Classification of BP based on ABPM – Consensus recommendations for categorizing patients based on office and ABPM measurements are outlined separately[27]. (See "Ambulatory blood pressure monitoring in children".)

The 2016 European Society of Hypertension (ESH) guidelines are similar for children <16 years but use higher thresholds for defining BP categories in older adolescents and adults. (See "Out-of-office blood pressure measurement: Ambulatory and self-measured blood pressure monitoring".)

●Association with target-organ damage – In adults, 24-hour ABPM has had better reproducibility and better correlation with the risk of hypertensive cardiovascular complications and target-organ damage compared with office BP measurements. (See "Overview of hypertension in adults", section on 'Ambulatory blood pressure monitoring'.)

Data are more limited in children but also indicate that ABPM is correlated with end-organ damage [10,27,47]. (See "Ambulatory blood pressure monitoring in children", section on 'Prediction of long-term risks'.)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Hypertension in children".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topic (see "Patient education: High blood pressure in children (The Basics)")

●Beyond the Basics topics (see "Patient education: High blood pressure in children (Beyond the Basics)" and "Patient education: High blood pressure treatment in children (Beyond the Basics)")

SUMMARY AND RECOMMENDATIONS

●Definition and importance – Hypertension in childhood and adolescence contributes to premature cardiovascular disease. In the United States, the diagnosis of persistent childhood hypertension is made when repeat blood pressure (BP) values on three separate visits are (table 1):

•Children <13 years – BP ≥95^th percentile for age, sex, and height, or ≥130/80 mmHg (whichever is lower) (table 2 and table 3)

•Children ≥13 years – BP ≥130/80

The diagnosis of hypertension is made when the auscultated BP values exceed these thresholds on three repeated and separate visits. Somewhat different definitions and/or different normative data are used in other countries. (See 'Diagnosis' above and 'Definitions' above.)

●Screening – Screening BP is performed as follows (see 'Screening of blood pressure' above):

•For children without risk factors or conditions associated with hypertension, BP is measured beginning at three years of age during annual health care supervision visits.

•For children ≥3 years of age with risk factors for hypertension, BP is measured at every health care encounter (table 5).

•For children <3 years of age with risk factors for hypertension, BP is measured at each health supervision visit (table 4).

Children with systolic BP (SBP) or diastolic BP (DBP) that exceeds screening thresholds for age and sex (table 6) require further evaluation, starting with repeat BP measurement (table 7).

●Measuring BP – Technique to ensure accurate measurements of BP include:

•Use an appropriately sized cuff, defined as a bladder width of 40 percent of the circumference of the upper arm and a bladder length that encircles 80 to 100 percent of the circumference of the upper arm. (See 'Cuff size and placement' above.)

•Perform the BP measurement in the right arm after the patient has been resting comfortably for at least three minutes in a seated position in a quiet environment. (See 'Technique of blood pressure measurement' above.)

•If the BP value exceeds the 90^th percentile by oscillometry, confirm it with an auscultatory measurement. (See 'Oscillometric devices' above.)

•In the initial evaluation for hypertension, perform BP measurements in both upper and lower extremities. At each visit, obtain at least two BP measurements spaced one or two minutes apart. (See 'Technique of blood pressure measurement' above and 'Number of measurements' above.)

•When performing an auscultatory BP measurement, use the first (initial tapping sound) and fifth (disappearance) Korotkoff sounds to identify SBP and DBP values, respectively. (See 'Technique of blood pressure measurement' above.)

●Ambulatory BP monitoring (ABPM) – Where available, ABPM should be used to confirm the diagnosis of hypertension in children. ABPM provides multiple measurements during regular activities (including sleep) and may give a more accurate description of the patient's BP and circadian patterns. (See "Ambulatory blood pressure monitoring in children".)