Paediatric hypertension for the primary care provider: What you need to know

Abstract

The prevalence of hypertension has increased in the paediatric and adolescent populations, and is estimated between 1% and 2% in Canada. Paediatric and adolescent hypertension differs from adult hypertension in many ways, and primary care providers may not be up to date with current guidelines and recommendations. Recently, the American Academy of Pediatrics updated and published guidelines on the diagnosis, evaluation, and management of hypertension in children and adolescents. This paper summarizes these new guidelines in addition to the existing Canadian guidelines in a simple four-step approach, catered to a primary care setting, detailing the diagnosis, evaluation, workup, and management of hypertension in children and adolescents.

Hypertension affects patients from across both paediatric and adult populations. Despite this, awareness of paediatric hypertension remains low (1). Understanding the basics of the diagnosis, management, and follow-up of hypertension is a skill necessary for both primary care physicians and paediatricians.

The prevalence of paediatric hypertension in Canada is approximately 2%, and is higher among adolescents and children with a history of prematurity, obesity, and renal disease (2,3). Moreover, the rate of obesity has risen dramatically among Canadian youth, doubling in the past half-decade (3). In a large population-based health measures survey, Shi et al. found that over 30% of children with hypertension were either overweight or obese. They also found that obese adolescents had an average of 7.6 mmHg higher systolic blood pressure than that of adolescents with a normal body mass index (BMI) (3).

The long-term risks of elevated blood pressure (BP) in children include chronic kidney disease (CKD), retinal vascular changes, and associated cardiovascular remodeling including elevated left ventricular mass and atherosclerosis (3,4). Lastly, elevated BP in childhood and adolescence is known to be associated with elevated BP and hypertension in adulthood (3).

The American Academy of Pediatrics (AAP) has recently released an updated clinical practice guideline for the diagnosis, evaluation, and management of paediatric hypertension (5). This revision updates the definition of hypertension previously used in the National Health Institution’s Fourth Report on High Blood Pressure in Children and Adolescents (6). This new guideline only used information from children with a normal BMI with the goal of creating ideal BP targets. This led to an average of a 2 to 3 mmHg decrease in BP targets when compared to previous normative values (7). In this way, the new guidelines resulted in an overall increase in the reported prevalence of hypertension when compared to the Fourth Report. Additionally, the new report expands the indications for a 24-hour ambulatory blood pressure monitor (ABPM) and offers new evidence with regards to the use of pharmacotherapy in the paediatric population (5).

This article aims to summarize the AAP guideline along with the existing 2018 Canadian Paediatric Hypertension Guideline (2,8). We provide a four-step approach to hypertension in children 1 to 18 years of age, catered to a primary care setting. Diagnosis and management of neonatal hypertension will not be discussed in this paper. We also encourage referencing the original guidelines if more comprehensive information is required for any aspect of this approach (2,5,8).

Step 1: screening for hypertension

Annual screening is recommended for all children and adolescents beginning at 3 years of age. Screening more frequently in this age group is indicated if there are specific hypertensive risk factors including (2,5):

• Obesity

• Diabetes

• Renal disease

• Aortic arch abnormalities

• Treatment with drugs known to raise BP

Additionally, there are certain indications for which patients less than 3 years of age should have their BP checked which includes (2,5)

• Gestational age <32 weeks

• Small for gestational age at birth or very low birth weight

• Use of an umbilical artery catheter

• Congenital heart disease

• Solid organ or bone marrow transplant

• Malignancy

• Increased intracranial pressure

• Personal history of renal disease (including urinary tract infections, hematuria, proteinuria)

• Family history of congenital renal disease

• Systemic disorders associated with hypertension

• Treatment with drugs known to raise BP

Step 2: diagnosing hypertension

Error in measurement is often the culprit of a missed or mistaken diagnosis of hypertension in children. BP should be measured in the right arm with an appropriate size cuff. Offices should be equipped with a variety of cuff sizes to accommodate infants as well as overweight young adults. The width of the bladder should equal 40% of the middle upper arm circumference and the length of the bladder should cover 80% to 100% of the arm circumference (5). Appropriate steps should be taken to ensure the child is comfortable and still for at least 5 minutes prior to measurement. Home BP measurements are not recommended when screening for new hypertension; however, they may be useful in monitoring BP once a patient has been diagnosed with hypertension.

Measurement with an automatic BP cuff (oscillation device) may be used to screen for elevated BP in the primary care setting. However, if the BP reading is elevated, it should be repeated with auscultation. If an auscultated BP measurement is elevated despite correct measurement technique, it should be repeated twice more at the same visit. The average of the last two auscultatory readings is then used as a final BP. The degree of elevation should be assessed based on this average with reference to normative BP values, as well as the revised hypertensive categories as outlined in Figure 1A (5). Having these normative BP values for age, gender, and height easily accessible in a provider’s clinic is suggested and is available in the full AAP guideline (5). Flynn et al. also outlined a useful table showing the minimum BP values for age and gender that would warrant further workup. This is displayed in Figure 1B (5). Of note, these BP cut-offs vary from those used in adults, which are based on the values at which the risks of cardiovascular, renal, and cerebrovascular incidents increase significantly (9).

Figure 1.

(A) Blood pressure (BP) categories and definitions. The lowest cut-off in each category should be used to make a diagnosis as outlined in the algorithm (5). If BP normalizes at any point, return to annual screening. (B) Shows the minimum systolic and diastolic BP that warrants further investigation for girls and boys, based on age (5).

A diagnosis of paediatric hypertension can be made if the BP remains at or above stage 1 hypertension on three separate clinic visits (5). The timeline for these follow-up BP assessments should be arranged as outlined in Figure 1A. Compared to adults, there is no strict BP cut-off for hypertensive crisis in children. Rather, severe hypertension warranting assessment in the emergency department depends on clinical symptoms, which may include irritability, headache, edema, visual changes, or severe abdominal pain (10–12).

As per the AAP guideline, ABPM may be useful when screening for, or in confirmingm, the diagnosis of hypertension in the following situations:

• BP remains in the elevated BP category for ≥1 year

• BP remains in the stage 1 hypertension category over three successive visits

• The patient has high risk conditions for hypertension (i.e., CKD, diabetes, obesity, or prematurity)

• Suspected white coat hypertension (up to 50% of children being evaluated for elevated BP) (8,13)

ABPM is superior to isolated BP measurements due to its accuracy and reproducibility in diagnosing hypertension, its ability to pick up on nocturnal BP measurements, and its ability to help identify secondary causes of hypertension. Additionally, ABPM can help predict future BP trends as well as end-organ damage such as left ventricular hypertrophy (13–15). Barriers to these recommendations in the community setting often include availability and cost of ABPM, as well as the need for a subspecialist referral.

Step 3: investigating the etiology of hypertension

Children and adolescents have a higher prevalence of secondary hypertension when compared to the adult population (6). Therefore, once a diagnosis of hypertension is made, a thorough screen for causative factors is warranted. Beginning with the history, topics that should be addressed include the child’s perinatal course, diet, exercise, obesity, medications, as well as their family history. Social history warrants particular attention as family income, parental education, poor sleep, and a lack of physical activity are independent risk factors for increased BP among Canadian youth (3). Clinicians are encouraged to screen for conditions that are likely to increase stress, including depression, anxiety, trauma, or bullying. A comprehensive physical exam should then be performed covering each of the systems involved in the differential diagnosis as outlined in Table 1 (5).

Table 1.

History, physical, and targeted investigations, organized by system to assess the etiology of hypertension

Cause	Clues from history and physical exam	Possible investigations
Primary hypertension	>6 years with: - Primary hypertension in a parent or grandparent - Overweight/obese - No suspicion for alternative cause	- Lipid profile - Electrolytes (sodium, potassium, chloride, bicarbonate) - Creatinine, BUN - UA - HbA1C, fasting glucose
Renovascular and renal (structural or glomerular abnormalities)	- Hematuria, edema, oliguria	- UA, electrolytes, BUN, creatinine, urine albumin: creatinine ratio - CBC - Renal US* - Renal US with Doppler**
Endocrine (hyperthyroidism, Cushing disease, type 2 diabetes mellitus, pheochromocytoma)	- Palpitations, tremors, sweating, headache - Acne, hirsutism, pubertal abnormalities - Family history of endocrine disease - Tachycardia	- TSH - HbA1C, fasting glucose - ACTH - Plasma and/or urine metanephrine/normetanephrine
Cardiac (aortic coarctation)	- Abnormal pulses - Upper + lower limb BP discrepancy	- Echocardiogram***
Respiratory (obstructive sleep apnea)	- Abnormal breathing during sleep - Tonsillar hypertrophy - Morning headaches, daytime fatigue	- Polysomnography
Genetic (Neurofibromatosis, Turner’s syndrome)	- Dysmorphic features	- Genetic testing
Medication	- History of herbal supplements, prescription or illicit drug use, or vitamins	- Drug screen

Bolded investigations are recommendations for all patients regardless of etiology. The remainder of the investigations may be indicated if there are clinical signs or symptoms suggestive of a systemic disorder, or for stage 2 or diastolic hypertension (5). *Renal US is recommended in all patients <6 years old with hypertension, regardless of etiology, OR in older children with abnormal renal function or urinalysis, to assess for renovascular disease (5). (Note, the Canadian guidelines recommend a renal ultrasound in all children with hypertension regardless of age [2].) **Renal US with Dopplers may be used in normal weight children ≥8 years old suspected of having renovascular hypertension (5). ***Echocardiogram is recommended to assess for target organ damage prior to starting pharmacologic treatment in patients with hypertension. It is not recommended as routine screening (3).

ACTH Adrenocorticotrophic hormone; BUN Blood urea nitrogen; CBC Complete blood count; HbA1c Hemoglobin A1c; TSH Thyroid stimulating hormone; UA Urinalysis; US Ultrasound.

All patients with hypertension should have electrolytes, creatinine, lipid profile, blood urea nitrogen, and a urinalysis checked. Patients less than 6 years old should undergo a renal ultrasound (5). Table 1 outlines suggested additional investigations according to suspected etiology. (Note, the Canadian guidelines recommend a renal ultrasound and fasting blood glucose in all children with hypertension, regardless of age [2].)

The most common etiology for hypertension by age and in order of prevalence are (16):

• 1 to 6 years: renal parenchymal disease, renovascular disease, endocrine, aortic coarctation, essential hypertension

• 6 to 12 years: renal parenchymal disease, essential hypertension, renovascular disease, endocrine, aortic coarctation, iatrogenic

• 12+ years: essential hypertension, iatrogenic, renal parenchymal disease, renovascular disease, endocrine, aortic coarctation

Step 4: first-line management of hypertension

Once the diagnosis of hypertension is made, a systematic approach to the management of this condition should be initiated. Treatment is crucial in preventing long-term sequelae of paediatric hypertension and has been shown to have the ability to reverse end-organ damage (5). In cases of secondary hypertension, effort should be made to treat the underlying etiology. The goals for management include targeting systolic and diastolic BPs <90th percentile or <130/80 mmHg for adolescents ≥13 years old (5). (Note the Canadian guidelines specify a treatment target of <95th percentile unless there is target organ damage, in which case a target of <90th percentile is then indicated [2].)

In all cases, the first step in management involves lifestyle modifications, such as exercise and diet modifications according to age (5,17). For those within the category of elevated BP, lifestyle modifications should be implemented for approximately 6 months, at which time the BP should be reassessed. Canadian guidelines recommend targeting a BMI of <85th percentile (2). The indications for initiating pharmacotherapy include failure of lifestyle modifications, symptomatic hypertension, evidence of target organ damage, comorbid diabetes or CKD, or stage 2 hypertension at presentation, as outlined in Figure 2 (2,3). Lifestyle modifications should then continue to be used alongside pharmacotherapy, and regular follow-up appointments are recommended to monitor the BP until it is within target. Referral to a subspecialist can be considered for hypertension that does not respond to 6 months of lifestyle modifications and is recommended for monotherapy resistant, secondary, stage 2, and symptomatic forms of hypertension. In remote areas where there might not be access to a paediatric nephrologist, clinicians can consider telephone or telehealth consultation with a specialist. If urgent or emergent, transfer to the nearest centre with paediatric subspecialty care may be warranted.

Figure 2.

Management and follow-up recommendations for paediatric hypertension. ACEi Angiotensin-converting enzyme inhibitor; ARB Angiotensin II receptor blocker; BMI Body mass index; CCB Calcium channel blocker; CKD Chronic kidney disease; DASH Dietary approaches to stop hypertension.*Indicates preferred treatment for patients with CKD and diabetes.

CONCLUSION

Paediatric hypertension remains a relatively prevalent diagnosis with significant long-term consequences. Several differences exist between hypertension in the paediatric and adult populations, specifically in regard to the diagnostic criteria and screening. In this paper we summarize current recommendations for the diagnosis and management of paediatric hypertension, specifically for a primary care physician or general paediatrician. Our systematic approach can help identify children with hypertension and facilitate initiating the appropriate investigations and treatment.

WHAT’S NEW

1. Screen children starting at age 3 with annual BP checks. Patients less than 3 with specific hypertensive risk factors may warrant BP checks at every clinical encounter.

2. Diagnosing hypertension is now based on normative values from nonobese children.

3. Revised definitions exist for the classification of paediatric hypertension.

4. The use of ABPM should be considered more frequently, such as in cases of suspected white coat hypertension, or to confirm hypertension for patients with elevated BP for more than 1 year.

Funding: There are no funders to report for this submission.

Potential Conflicts of Interest: All authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.