PatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
There is no current standard UK definition of hypertension in children. However, the issue has been researched in some detail in the USA, where a working group in 2004 defined the condition as an average systolic and/or diastolic blood pressure ≥95th percentile for gender, age and height on three or more separate occasions. The working group also introduced the concept of 'pre-hypertension' which it defines as a blood pressure level ≥90th percentile but <95th percentile.
As with adults, blood pressure varies between individuals and within individuals from day to day and at various times of the day. Attention must be paid to correct technique in measuring blood pressure and with small patients this includes the use of a small cuff. The traditional method of auscultation of 1st and 5th Korotkoff sounds, using a mercury sphygmomanometer, gives an accuracy that is second only to direct cannulation of the artery. Nowadays mercury and aneroid instruments are being replaced by electronic or Doppler devices.
White coat hypertension and masked hypertension may be particularly relevant in children. One study found that ambulatory blood pressure measurement correlated quite well with home monitoring and the latter is becoming a validated method. Whatever method is used, the instrument must be regularly checked for accuracy and serviced and used correctly.
See the link to the article by Kaelber, under 'Further reading & references' at the end of this article, to provide an indication of the levels of blood pressure in children and adolescents that require further evaluation.
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The prevalence of hypertension in children is increasing due to the rise in obesity in children.
Based on the use of ≥95th percentile to define hypertension, it would be expected that the prevalence of hypertension would be approximately 5%. However, due to regression to the mean with repeated measures, the prevalence of hypertension is lower than 5%.
A study in USA determined the prevalence of hypertension to be 3.6% and the prevalence of pre-hypertension to be 3.4% in children and adolescents between the ages of 3 years and 18 years.
One study found that organ damage, such as left ventricular hypertrophy, thickening of the carotid vessel wall, retinal vascular changes and even subtle cognitive changes, were detectable in children and adolescents with high blood pressure and the authors of this study considered that hypertension was a common long-term health problem in this age group.
In the absence of overt disease that will cause hypertension, there are a number of factors known to affect blood pressure in children and young adults. These are:
- Salt intake - this is very important. Processed and convenience foods tend to be very high in salt.
- Obesity - childhood obesity increases the risk of childhood hypertension.
- Low birth weight - this seems to be a particular risk factor in patients who subsequently have a high BMI.
The condition is usually asymptomatic but may be revealed fortuitously during examination in patients with suspected underlying conditions such as kidney disease or coarctation of the aorta.
There are a few presenting features that should raise the possibility of hypertension:
- Failure to thrive
- Irritability or lethargy
- Respiratory distress
- Congestive cardiac failure
In older children
If the condition is found, enquiry should be made for certain features in the child's history:
- Bronchopulmonary dysplasia.
- History of umbilical catheterisation.
- Head or abdominal trauma.
- Familial diseases - eg, neurofibromatosis, hypertension and multiple endocrine neoplasia, especially if associated with phaeochromocytoma.
- History of pyelonephritis may have been missed - ask about pyrexia of unknown origin, as urinary tract infection in children is not always overt.
- Medication may have a pressor effect - for example, children on steroids, those taking amfetamines for attention deficit hyperactivity disorder, and those abusing drugs.
- Ask about diet, looking for high salt intake and possibly high consumption of liquorice.
- Examination of the child starts with looking at the general state of nutrition and apparent state of health. Check height and weight against centile charts.
- Blood pressure:
- Examination of the pulse precedes measurement of blood pressure.
- The child should be seated and relaxed or supine if a baby.
- The cuff is placed around the right arm at the level of the heart.
- The rubber blade inside the cloth cover should be long enough to encircle the arm and wide enough to cover approximately three quarters of the distance from shoulder to elbow.
- Examine the rest of the cardiovascular system. Check for displacement of the apex beat and signs of left ventricular hypertrophy. Heart murmurs in children may be relevant. Also feel the pulses in the lower limbs. If the amplitude of the pulse is poor this suggests coarctation of the aorta.
- Look for stigmata of specific diseases:
In general, the younger the child and the higher the blood pressure the greater the chance of identifying the cause. 80% are due to renal parenchymal abnormality. The table gives the order of frequency of the various causes of hypertension in four age groups:
Causes of Childhood Hypertension According to Age Group
|1 to 6 years||Renal parenchymal disease; renal vascular disease; endocrine causes; coarctation of the aorta; essential hypertension|
|6 to 12 years||Renal parenchymal disease; essential hypertension; renal vascular disease; endocrine causes; coarctation of the aorta; iatrogenic illness|
|12 to 18 years||Essential hypertension; iatrogenic illness; renal parenchymal disease; renal vascular disease; endocrine causes; coarctation of the aorta|
Most adults are deemed to have essential hypertension and little or no further investigation is undertaken but in children a cause for the hypertension should be sought. Basic screening tests to detect underlying pathology should be carried out together with investigations to assess comorbidity and end organ damage.
Further testing may be required, depending on individual and family histories, the presence of risk factors and the results of the screening tests. The younger the child is at presentation and the more severe the blood pressure abnormality, then the more likely that there is a secondary cause of hypertension.
To identify the cause
- Urine - check for albumin and blood
- U&Es and creatinine - to assess renal function; low potassium may suggest elevated aldosterone
- FBC - may reveal anaemia consistent with renal disease
- Renal ultrasound - to exclude abnormalities of renal morphology
To identify comorbidities
- Drug screen - this may be relevant in adolescents to exclude ingestion of recreational drugs
- Fasting lipids and glucose - to rule out hyperlipidaemia, metabolic syndrome, diabetes
- Polysomnography - to establish the existence of a sleep disorder, which may be linked to hypertension
To identify end organ damage
- ECG - may show left ventricular hypertrophy or strain
- Echocardiography - can show hypertrophy and abnormal function
- Retinal examination - may identify retinal vascular changes
Additional tests as clinically indicated
- 24-hour urine for protein and creatinine, creatinine clearance - to exclude chronic renal disease
- Advanced imaging - magnetic resonance angiogram, duplex Doppler flow studies; 3-dimensional computed tomography; arteriography (classic or digital subtraction), may be required to exclude renovascular abnormalities
- Ambulatory blood pressure monitoring - may be needed to exclude white coat hypertension
- TFTs - to rule out thyrotoxicosis
- Plasma aldosterone - a high concentration is diagnostic of hyperaldosteronism
- Plasma catecholamines or urine catecholamines and catecholamine metabolites - high levels are diagnostic of phaeochromocytoma or neuroblastoma
- Plasma renin levels:
- High plasma renin activity indicates renal vascular hypertension, including coarctation of the aorta.
- Very low plasma renin activity suggests glucocorticoid remediable aldosteronism or apparent mineralocorticoid excess.
Hypertension in children and adolescents is treated with lifestyle changes, including weight loss if indicated, a healthy, low-sodium diet, regular physical activity and avoidance of tobacco and alcohol. Children with symptomatic hypertension, secondary hypertension, target organ damage, diabetes or persistent hypertension despite non-pharmacological measures should be treated with antihypertensive medications.
This includes weight control, encouragement of exercise, reduction in dietary sodium and fat and, where appropriate, cessation of smoking and alcohol. it is essential to assess and, wherever possible, modify all cardiovascular risk factors.
Acceptable drug classes for use in children with hypertension include angiotensin-converting enzyme (ACE) inhibitors, alpha-blockers, beta-blockers, calcium-channel blockers and thiazide diuretics. There is limited information on the use of angiotensin-II receptor antagonists in children.
Diuretics and beta-blockers have a long history of safety and efficacy in children. ACE inhibitors and calcium-channel blockers have been shown to be safe and effective in short-term studies in children. Refractory hypertension may require additional treatment with agents such as minoxidil.
- Thiazides and beta blockers - these have the best track record in terms of safety and efficacy.
- ACE inhibitors and calcium-channel blockers - these are gradually gaining preference as first-line drugs in view of their low side-effect profile. Caution may need to be exerted when using ACE inhibitors in patients with renal disease but they can be helpful in some cases.
- Angiotensin-II receptor antagonists - their role is currently being evaluated. One study found that the blood pressure reduction of ACE inhibitors, angiotensin-II receptor antagonists and calcium-channel blockers was almost identical. In children with pathological proteinuria, ACE inhibitors or angiotensin-II receptor antagonists were superior to calcium-channel blockers.
Management of a hypertensive crisis
- An acute hypertensive crisis may be the result of an acute illness, such as glomerulonephritis or acute kidney injury, drugs or psychogenic substances, or exacerbation of moderate hypertension.
- A hypertensive crisis can present with features of cerebral oedema, seizures, heart failure, pulmonary oedema, or renal failure.
- The accurate assessment of blood pressure is essential when a patient has a seizure, particularly when no epileptic disorder is known.
- Anticonvulsant drugs are ineffective to treat convulsions in a hypertensive crisis. Suitable drugs include nifedipine, labetalol and sodium nitroprusside. Newer rapid-acting drugs such as clevidipine have been developed.
- The aim is to decrease blood pressure to normal within several hours. Close supervision is required to avoid an excessively rapid decrease in blood pressure that may result in underperfusion.
- A Cochrane review concluded that further research was needed to determine which drugs were best for the treatment of hypertensive crisis and their effect on morbidity and mortality.
- This is dependent upon the underlying cause. Experience from adults shows that poorly controlled blood pressure is a risk factor for coronary heart disease and is the major risk factor for stroke.
- Children with raised blood pressure are more likely to become hypertensive adults.
- There are no definitive data to link childhood blood pressure with cardiovascular risk but extrapolation of other data would suggest that, if hypertension is poorly controlled from an early age, morbidity or mortality will also strike early.
Further reading & references
- Kaelber DC; Simple table to Identify children and adolescents needing further evaluation of blood pressure. Pediatrics Vol. 123 No. 6 June 1, 2009.
- Falkner B, Daniels SR; Summary of the Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents. Hypertension. 2004 Oct;44(4):387-8. Epub 2004 Sep 7.
- Stergiou GS, Nasothimiou E, Giovas P, et al; Diagnosis of hypertension in children and adolescents based on home versus ambulatory blood pressure monitoring. J Hypertens. 2008 Aug;26(8):1556-62.
- Parati G, Stergiou GS, Asmar R, et al; European Society of Hypertension guidelines for blood pressure monitoring at home: a summary report of the Second International Consensus Conference on Home Blood Pressure Monitoring. J Hypertens. 2008 Aug;26(8):1505-26.
- Falkner B; Hypertension in children and adolescents: epidemiology and natural history. Pediatr Nephrol. 2009 May 7.
- Hansen ML, Gunn PW, Kaelber DC; Underdiagnosis of hypertension in children and adolescents. JAMA. 2007 Aug 22;298(8):874-9.
- Lambert M, Delvin EE, Levy E, et al; Prevalence of cardiometabolic risk factors by weight status in a population-based sample of Quebec children and adolescents. Can J Cardiol. 2008 Jul;24(7):575-83.
- Strufaldi MW, Silva EM, Franco MC, et al; Blood pressure levels in childhood: probing the relative importance of birth weight and current size. Eur J Pediatr. 2009 May;168(5):619-24. Epub 2008 Oct 2.
- Luma GB, Spiotta RT; Hypertension in children and adolescents. Am Fam Physician. 2006 May 1;73(9):1558-68.
- Bixler EO, Vgontzas AN, Lin HM, et al; Blood pressure associated with sleep-disordered breathing in a population sample of children. Hypertension. 2008 Nov;52(5):841-6. Epub 2008 Oct 6.
- McCrindle BW; Assessment and management of hypertension in children and adolescents. Nat Rev Cardiol. 2010 Mar;7(3):155-63. doi: 10.1038/nrcardio.2009.231. Epub 2010 Jan 12.
- Riley M, Bluhm B; High blood pressure in children and adolescents. Am Fam Physician. 2012 Apr 1;85(7):693-700.
- British National Formulary
- Robinson RF, Nahata MC, Batisky DL, et al; Pharmacologic treatment of chronic pediatric hypertension. Paediatr Drugs. 2005;7(1):27-40.
- Simonetti GD, Rizzi M, Donadini R, et al; Effects of antihypertensive drugs on blood pressure and proteinuria in childhood. J Hypertens. 2007 Dec;25(12):2370-6.
- Varon J; The diagnosis and treatment of hypertensive crises. Postgrad Med. 2009 Jan;121(1):5-13.
- Perez MI, Musini VM; Pharmacological interventions for hypertensive emergencies. Cochrane Database Syst Rev. 2008 Jan 23;(1):CD003653.
- Management of high blood pressure in children and adolescents; European Society of Hypertension, 2009
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.
Dr Laurence Knott
Dr Colin Tidy
Dr Adrian Bonsall