Pediatric Hypertension - Diagnosis

Because pediatric hypertension is often secondary to another disease process (like kidney disease), an elevated blood pressure measurement can be another way to tease out as early as possible, the seriously ill child that doesn’t really look that bad. Such a child might look like the little girl in Dr. Mellick’s YouTube video, Hemolytic Uremic Syndrome, 8:15, Published on Jul 17, 2015.

What constitutes hypertension in pediatric patients depends on the patient’s age, sex, and height. So you have to first check the blood pressure and then look it up in a table – at the least, a time drain.

So for convenience I have included a simplified chart from the Pediatric Hypertension Guidelines of the Royal Children’s Hospital of Melbourne. (1) If the child’s blood pressure exceeds the number on the chart, you’ll need to go to the more detailed charts in Resource (2).

Here is the simplified chart:

PEDIATRICS Vol. 123 No. 6 June 2009, pp. e972-e974

What follows is from Resource (2):

DEFINITION OF HYPERTENSION
• Hypertension is defined as average SBP and/or diastolic BP (DBP) that is >/or = 95th percentile for gender, age, and height on >/or = occasions.
• Prehypertension in children is defined as average SBP or DBP levels that are >/or = to 90th percentile but < 95th percentile.
• As with adults, adolescents with BP levels >/or = 120/80 mm Hg should be considered prehypertensive.
• A patient with BP levels 95th percentile in a physician’s office or clinic, who is normotensive outside a clinical setting, has “white-coat hypertension.” Ambulatory BP monitoring (ABPM) is usually required to make this diagnosis.

The definition of hypertension in children and adolescents
is based on the normative distribution of
BP in healthy children. Normal BP is defined as SBP
and DBP that are < 90th percentile for gender, age,
and height. Hypertension is defined as average SBP
or DBP that is >/or = 95th percentile for gender, age, and
height on at least 3 separate occasions. Average SBP
or DBP levels that are >/or = 90th percentile but < 95th
percentile had been designated as “high normal” and
were considered to be an indication of heightened
risk for developing hypertension.

MEASUREMENT OF BP IN CHILDREN
• Children 3 years old who are seen in a medical setting should have their BP measured.
• The preferred method of BP measurement is auscultation.
• Correct measurement requires a cuff that is appropriate to the size of the child’s upper arm. • Elevated BP must be confirmed on repeated visits before characterizing a child as having hypertension.
• Measures obtained by oscillometric devices that exceed the 90th percentile should be repeated by auscultation.

Children 3 years old who are seen in medical care settings should have their BP measured at least once during every health care episode. Children < 3 years old should have their BP measured in special circumstances (see Table 1).

The BP tables are based on auscultatory measurements; therefore, the preferred method of measurement is auscultation. As discussed below, oscillometric devices are convenient and minimize observer error, but they do not provide measures that are identical to auscultation. To confirm hypertension, the BP in children should be measured with a standard clinical sphygmomanometer, using a stethoscope placed over the brachial artery pulse, proximal and medial to the cubital fossa, and below the bottom edge of the cuff (ie, 2 cm above the cubital
fossa). The use of the bell of the stethoscope may allow softer Korotkoff sounds to be heard better.3,4

Preparation of the child for standard measurement can affect the BP level just as much as technique.5 Ideally, the child whose BP is to be measured should have avoided stimulant drugs or foods, have been sitting quietly for 5 minutes, and seated with his or her back supported, feet on the floor and right arm supported, cubital fossa at heart level.6,7 The right arm is preferred in repeated measures of BP for consistency and comparison with standard tables and because of the possibility of coarctation of the aorta, which might lead to false (low) readings in the left arm.8

By convention, an appropriate cuff size is a cuff with an inflatable bladder width that is at least 40% of the arm circumference at a point midway between the olecranon and the acromion (see www.americanheart.org/presenter.jhtml identifier576).9,10 For such a cuff to be optimal for an arm, the cuffbladder length should cover 80% to 100% of the circumference of the arm.1,11 Such a requirement demands that the bladder width-to-length ratio be at least 1:2. Not all commercially available cuffs are manufactured with this ratio. Additionally, cuffs labeled for certain age populations (eg, infant or child cuffs) are constructed with widely disparate dimensions. Accordingly, the working group recommends
that standard cuff dimensions for children be adopted (see Table 2). BP measurements are overestimated to a greater degree with a cuff that is too small than they are underestimated by a cuff that is too large. If a cuff is too small, the next largest cuff
should be used, even if it appears large. If the appropriate
cuffs are used, the cuff-size effect is obviated.12

Auscultation remains the recommended method of BP in children under most circumstances. Oscillometric devices measure mean arterial BP and then calculate systolic and diastolic values.16 The algorithms used by companies are proprietary and differ from company to company and device to device. These devices can yield results that vary widely when one is compared with another,17 and they do not always closely match BP values obtained by auscultation.18 Oscillometric devices must be validated on a regular basis.

Two advantages of automatic devices are their ease of use and the minimization of observer bias or digit preference.16 Use of the automated devices is preferred for BP measurement in newborns and young infants, in whom auscultation is difficult, and in the intensive care setting, in which frequent BP measurement is needed. An elevated BP reading obtained with an oscillometric device should be repeated by using auscultation.

ABPM

ABPM refers to a procedure in which a portable BP device, worn by the patient, records BP over a specified period, usually 24 hours. ABPM is very useful in the evaluation of hypertension in children.21–23 By frequent measurement and recording of BP, ABPM enables computation of the mean BP during the day, night, and over 24 hours as well as various measures to determine the degree to which BP exceeds the upper limit of normal over a given time period, ie, the BP load. ABPM is especially helpful in the evaluation of white-coat hypertension as well as the risk for hypertensive organ injury, apparent drug resistance, and hypotensive symptoms with antihypertensive drugs. . . . Conducting ABPM requires specific equipment
and trained staff. Therefore, ABPM in children
and adolescents should be used by experts in the
field of pediatric hypertension who are experienced
in its use and interpretation.

See the blood pressure tables in Resource (2). The blood pressure tables are on pages 9 through 13 of the document.

■ BP standards based on sex, age, and height provide a precise classification of BP according to body size.

■ The revised BP tables now include the 50th, 90th, 95th, and 99th percentiles (with standard deviations) by sex, age, and height.

USING THE BLOOD PRESSURE TABLES

1. Use the standard height charts to determine the height percentile.

2. Measure and record the child’s SBP and DBP.

3. Use the correct gender table for SBP and DBP.

4. Find the child’s age on the left side of the table. Follow the age row horizontally across the table to the intersection of the line for the height percentile (vertical column).

5. There, find the 50th, 90th, 95th, and 99th percentiles for SBP in the left columns and for DBP in the right columns. ■ BP less than the 90th percentile is normal. ■ BP between the 90th and 95th percentile is prehypertension. In adolescents, BP equal to or exceeding 120/80 mmHg is prehypertension, even if this figure is less than the 90th percentile. ■ BP greater than the 95th percentile may be hypertension.

6. If the BP is greater than the 90th percentile, the BP should be repeated twice at the same office visit, and an average SBP and DBP should be used.

7. If the BP is greater than the 95th percentile, BP should be staged. If Stage 1 (95th percentile to the 99th percentile plus 5 mmHg), BP measurements should be repeated on two more occasions. If hypertension is confirmed, evaluation should proceed as described in table 7. If BP is Stage 2 (>99th percentile plus 5 mmHg), prompt referral should be made for evaluation and therapy. If the patient is symptomatic, immediate referral and treatment are indicated. Those patients with a compelling indication, as noted in table 6, would be treated as the next higher category of hypertension.

Primary Hypertension and Evaluation for Comorbidities

■ Primary hypertension is identifiable in children and adolescents.

■ Both hypertension and prehypertension have become a significant health issue in the young due to the strong association of high BP with overweight and the marked increase in the prevalence of overweight children.

■ The evaluation of hypertensive children should include assessment for additional risk factors.

■ Due to an association of sleep apnea with overweight and high BP, a sleep history should be obtained.

High BP in childhood had been considered a risk factor for hypertension in early adulthood. However, primary (essential) hypertension is now identifiable in children and adolescents. Primary hypertension in childhood is usually characterized by mild or Stage 1 hypertension and is often associated with a positive family history of hypertension or cardiovascular disease (CVD). Children and adolescents with primary hypertension are frequently overweight. Data on healthy adolescents obtained in school healthscreening programs demonstrate that the prevalence of hypertension increases progressively with increasing body mass index (BMI), and hypertension is detectable in approximately 30 percent of overweight children (BMI >95th percentile).26 The strong association of high BP with obesity and the marked increase in the prevalence of childhood obesity27 indicate that both hypertension and prehypertension are becoming a significant health issue in the young.

Primary hypertension often clusters with other risk factors.31,32 Therefore, the medical history, physical examination, and laboratory evaluation of hypertensive children and adolescents should include a comprehensive assessment for additional cardiovascular risk. These risk factors, in addition to high BP and overweight, include low plasma HDL-C, elevated plasma triglyceride, and abnormal glucose tolerance.

To identify other cardiovascular risk factors, a fasting lipid panel and fasting glucose level should be obtained in children who are overweight and have BP between the 90th and 94th percentile and in all children with BP greater than the 95th percentile. If there is a strong family history of type 2 diabetes, a hemoglobin A1c or glucose tolerance test may also be considered.

Sleep disorders, including sleep apnea, are associated with hypertension, coronary artery disease, heart failure, and stroke in adults.33,34 Although limited data are available, they suggest an association of sleep-disordered breathing and higher BP in children.35,36

Approximately 15 percent of children snore, and at least 1–3 percent have sleep-disordered breathing.35 Because of the associations with hypertension and the frequency of occurrence
of sleep disorders, particularly amongoverweight children, a history of sleepingpatterns should be obtained in a child with
hypertension. One practical strategy for identifying children with a sleep problem or sleep disorder is to obtain a brief sleep history, using an instrument called BEARS.37(table 1.1)

BEARS addresses five major sleep domains that provide a simple but comprehensive screen for the major sleep disorders affecting children ages 2–18. The components of BEARS include: Bedtime problems, Excessive daytime sleepiness, Awakenings during the night, Regularity and duration of sleep, and Sleep-disordered breathing (snoring). Each of these domains has an age-appropriate trigger question and includes responses of both parent and child, as appropriate. This brief screening for sleep history can be completed in about 5 minutes.

BEARS Sleep Screening Tool

Evaluation for Secondary Hypertension

■ Secondary hypertension is more common in children than in adults.

■ Because overweight is strongly linked to hypertension, BMI should be calculated as part of the physical examination.

■ Once hypertension is confirmed, BP should be measured in both arms and in a leg.

■ Very young children, children with Stage 2 hypertension, and children or adolescents with clinical signs that suggest systemic conditions associated with hypertension should be evaluated more completely than in those with Stage 1 hypertension.

Secondary hypertension is more common in children than in adults. The possibility that some underlying disorder may be the cause of the hypertension should be considered in every child or adolescent who has elevated BP. However, the extent of an evaluation for detection of a possible underlying cause should be individualized for each child. Very young children, children with Stage 2 hypertension, and children or adolescents with clinical signs that suggest the presence of systemic conditions associated with hypertension should be evaluated more extensively as compared to those with Stage 1 hypertension.38 Present technologies may facilitate less invasive evaluation than in the past, although experience in using newer modalities with children is still limited.

PHYSICAL EXAMINATION

The child’s height, weight, and percentiles for age should be determined at the start of the physical examination. Because obesity is strongly linked to hypertension, BMI should be calculated from the height and weight, and the BMI percentile should be calculated. Poor growth may indicate an underlying chronic illness. When hypertension is confirmed, BP should be measured in both arms and in a leg. Normally, BP is 10–20 mmHg higher in the legs than the arms. If the leg BP is lower than the arm BP, or if femoral pulses are weak or absent, coarctation of the aorta may be present. Obesity alone is an insufficient explanation for diminished femoral pulses in the presence of high BP. The remainder of the physical examination should pursue clues found on history and should focus on findings that may indicate the cause and severity of
hypertension. Table 8 lists important physical exam findings in hypertensive children.39

The physical examination in hypertensive children is frequently normal except for the BP elevation. The extent of the laboratory evaluation is based on the child’s age, history, physical examination findings, and level of BP elevation. The majority of children with secondary hypertension will have renal or renovascular causes for the BP elevation.

Periorbital edema can be caused by renal disease as by many other causes.

This list is from Eyelid Swelling from fpnotebook.com:

IV. Causes: Systemic edematous conditions with Eyelid Edema

Angioedema

Congestive Heart Failure

Hypothyroidism

Renal Failure

Now resuming excerpts from Resource (2)

Target-Organ Abnormalities in Childhood Hypertension

■ Target-organ abnormalities are commonly associated with hypertension in children and adolescents.

■ Left ventricular hypertrophy (LVH) is the most prominent evidence of target-organ damage.

■ Pediatric patients with established hypertension should have echocardiographic assessment of left ventricular mass at diagnosis and periodically thereafter.

■ The presence of LVH is an indication to initiate or intensify antihypertensive therapy.

Hypertension is associated with increased risk of myocardial infarction, stroke, and cardiovascular mortality in adults,2,51 and treatment of elevated BP results in a reduction in the risk for cardiovascular events.