Download - Hypertension in children vevey february 2010

Hypertension in childrenHypertension in children

F. Cachat

Pediatrics and Pediatric Nephrology

Vevey and Lausanne

Switzerland

Disease prevalence in childhood

Disease prevalence in childhood

• Congenital heart disease 1%

• Epilepsy 3-5%

• ADHD 3-5%

• Hypertension 4-5%

• Asthma 7%

• Obesity 18-25%

HTN is a major killer in adulthood

Some HTN originates in childhood

Many children with HTN during infancy will stillhave HTN as adults (blood pressure tracking)

PLANPLAN

• Definition

• Case presentation

• Physiology of hypertension in children (some aspects)

• Evaluation of the child with hypertension (some aspects)

• Management of the child with hypertension (some aspects)

• Conclusion

DefinitionsDefinitions

• Update on the 1996 and 1987 Task Force Report on

High Blood Pressure in Children and Adolescents:– 60’000 healthy children

– M/F: 50/50

– White: 56%, African-American: 29%, Spanish: 9%, Asian:

3%, Others: 3%


Classification of Hypertension in Childrenand Adolescents

Classification of Hypertension in Childrenand Adolescents

SBP or DBP Percentile

Normal <90th percentile

Prehypertension 90th percentile to <95th percentile, or if BP exceeds 120/80 mm Hg, even if below the 90th percentile up to <95th percentile

Stage 1 hypertension 95th percentile to the 99th percentile + 5 mm Hg

Stage 2 hypertension >99th percentile + 5 mm Hg

How to calculate the 95th percentile of BP for a child?How to calculate the 95th

percentile of BP for a child?

– Systolic BP (1-17 years)• 100 + (age in years x 2)

– Diastolic BP (1-10 years)• 60 + (age in years x 2)

– Diastolic BP (11-17 years)• 70 + (age in years)

Case presentationCase presentation

Case presentationsCase presentations

• Case 1: monogenic hypertension

• When a rare single genetic disease helps to understand the pathophysiology of HTN in children

• When HTN treatment benefits are obvious

• Case 2: obesity related hypertension

• A rising epidemic of HTN in children in the Western World• When HTN treatment benefits are less obvious (and treatment more

difficult)• Polygenic, multifactorial HTN

HTN

Sub-arachn.hemorrhage

BP 160/110 mm HgHx of surgically-corrected VUR

HTN



Premature death 36 years oldSub-arachn. hemorrhage

Physical examPhysical exam

• NORMAL except for confirmed severe asymptomatic HTN (discovered during routine school exam)

Laboratory valuesLaboratory values

• Plasma chemistries : Na 141 mmol/l, K 2.8 mmol/l, creatinine 71 mol/l, bicarbonates 27 mmol/l, BE + 3.2 mmol/l, glucose 5.3 mmol/l, calcium 2.37 mmol/l

• Urine chemistries : Na 113 mmol/l, K 75 mmol/l, no proteinuria, no glycosuria

• I123-Hippuran scintigraphy : normal, no scars

• Father’s plasma potassium : 3.2 mmol/l

Laboratory valuesLaboratory values

• Plasma renin activity: extremely low

• Plasma aldosterone: extremely high

• Plasma and urine cortisol : normal values

In summaryIn summary

• An autosomal dominant form of severe HTN

• With hypokalemia and alkalosis

• With very high aldosterone levels and suppressed renin activity

Na Intake

Kidneys

Urinary sodium

Renin

Blood volumeBlood pressure

Na and Cl transport

Aldosterone

ACTH

GRA

Congenital Adrenal hyperplasia

Deoxycorticosterone

Cortisol

Cortisone

ENaC(Liddle’ssyndrome)

Gordon syndrome

AME

Monogenic endocrine HTN

15-year-old boy

No past medical historyNo medicationFound by the pediatrician

to have sustained HTN 140/85 mm Hg

Extensive work-up negativeFamily history positive for

both parents having HTN

http://www.phillip-lee.com/content/Blog_Images/child%20obesity_m.jpg

http://www.innovationcanada.ca/28/images/hypertension_z.jpg

Conservative treatment/diet

No major changes in dietcontinues to eat saltyfood (salt sensitivity)

Pharmacological treatmentPoor compliance with

drug treatment (drug compliance)

Poor BP (and weight) improvement

http://www.phillip-lee.com/content/Blog_Images/child%20obesity_m.jpg

http://a123.g.akamai.net/f/123/12465/1d/media.canada.com/reuters/test_reutersushealthonlinereport_iptc/2007-11-10t172706z_01_nootr_rtridsp_2_health-obesity-emotions-dc.jpg?size=l

http://www.jeffhayes.com/art/images/salt_shaker.jpg

http://content.ytmnd.com/content/b/d/f/bdf93a6505611fe13a011d49049229f1.jpg

PathophysiologyPathophysiology

Child at risk

Birth weight

Sex

Genetics

Adult with ± cardio-vascular risks

Physical activity

Job/social factorsWeightWeight gainObesityTruncal obesity

Food (fat, sodium) Smoking/environmental factors

Renal injury

Cardiac abnormality(coarctation of theAorta)

Endocrine abnormality

Programmeddeterminants Secondary

insults

Life style

Child at risk

Birth weight

Sex

Genetics


Physical activity



Renal injury



HTN



Premature death 36 years oldSub-arachn. hemorrhage

GRAAME

Liddle syndrome

Child at risk

Birth weight

Sex

Genetics


Physical activity



Renal injury



Relationship between blood pressure values and birth weightRelationship between blood pressure values and birth weightBarker DJP Schweiz Med Wochenschrift 1999;129:189-196Barker DJP Schweiz Med Wochenschrift 1999;129:189-196

f/u of BP in former premature infants with or without growth retardation in Lausanne (14-16

years)

f/u of BP in former premature infants with or without growth retardation in Lausanne (14-16

years)

Systolic BP (mm Hg) Diastolic BP (mm Hg)

Controls 123±11 71±5*

Premature infants**without growth retardation 129±13 86±9

Premature infants**with growth retardation 129±17 87±6

*P<0.0001 compared to premature with and without intrauterine growth retardation (unpaired t-test)Premature infants defined as 32 weeks gestational age

0%

5%

10%

15%

20%

<2.5 kg (270) 2.5-4.0 kg (3979) >4.0 kg (405)

% with elevated BP

at 12 y(at 1st visit)

16.7

10.616.711.2

Etude Chiolero-IUMSP

Relation between birth weight and blood pressure (systolic blood pressure)

Child at risk

Birth weight

Sex

Genetics


Physical activity



Renal injury



Background

• Obesity is increasingly frequent among children worldwide• There is a fear that obesity related conditions might

increase, such as hypertension • Few data on prevalence of hypertension among children,

especially in European countries• Most epidemiological studies assessed blood pressure (BP)

on one visit, hence BP was overestimated

Aims

• To assess prevalence of hypertension measured on up to three visits in a Swiss pediatric population

• To assess the relationship between hypertension, being overweight and other factors

Methods

• All children of the 6th grade of the schools of canton of Vaud (N=6873) were eligible and 5207 participated (76%).

• Weight, height, and blood pressure (BP) were measured.

• At initial visit, three BP readings were obtained with a clinically validated automated device.

Methods

• IOTF criteria for use for overweight/obesity.

• Elevated BP was defined for average of two last BP readings >95th sex-, age- and height specific percentiles (US reference).

• If BP was elevated at the initial visit, BP was measured on up to two additional separate visits.

• Hypertension is defined for elevated BP on the three visits (recommendation of NHBPEP)

10.5

12.4

4.0 3.72.3 2.0

0

5

10

15

1st visit 2nd visit 3rd visit

Boys Girls

Prevalence of elevated BP at each visit

Hypertension

Four fold decrease in the prevalence of elevated BP between 1st and 3rd visit

Probably lower prevalence than in US children (4-9%).

Results

High prevalence of overweight, relatively low compared to other regions of Europe

Underestimation as some overweight/obese children did not participate

Results

Boys GirlsN 2621 2586Mean age (SD) [range], year 12.3 (0.5) 12.3 (0.5)

[10.1-14.9] [10.3-14.8]BMI categories (IOTF*) (SE), % No excess weight 85.0 (0.7) 87.6 (0.6) Overweight (not obese) 13.3 (0.7) 10.7 (0.6) Obese 1.8 (0.3) 1.7 (0.3) Overweight or obese 15.0 (0.7) 12.4 (0.6)

BP strongly relates to BMI

The association between BP and BMI is independent of age and height

Blood pressure and body mass index

Girls

0

20

40

60

80

100

120

140

160

10 20 30 40

Diastolic Systolic

Boys

0

20

40

60

80

100

120

140

160

10 20 30 40

Diastolic Systolic

BP (mmHg)

BMI (kg/m2)

Results

1.7 1.22.0

3.8

14.9

0

5

10

15

20

<25th 25th-74th 75th-84th 85th-94th >=95th

BMI percentile (CDC)

Hyp

ert

en

sio

n (

%)

Results Prevalence of hypertension according to BMI category

ConclusionConclusion

1) Prevalence of overweight and obesity in children aged 12 years old was high but relatively low compared to other regions of Europe

2) Prevalence of hypertension was highly dependent on the number of visits at which BP was measured

3) HTN prevalence was low, and increased with increase in BMI

Evaluation of HTN in childrenEvaluation of HTN in children

History taking

Child at risk

Birth weight

Sex

Genetics


Physical activity



Renal injury



Physical exam

Child at risk

Birth weight

Sex

Genetics


Physical activity



Renal injury



Cushing syndrome

Henoch-Schoenlein purpura

Lab investigations

Child at risk

Birth weight

Sex

Genetics


Physical activity



Renal injury



ChildrenChildren

Secondary causesSecondary causesRenal causes Renal causes (78%)(78%)

Reno-vascular causes Reno-vascular causes (12%)(12%)

Coarctation Aorta Coarctation Aorta (2%)(2%)

Other causes Other causes (endocrine(endocrinecauses, phaeo) (8%)causes, phaeo) (8%)

(Essential HTN)(Essential HTN)

AdultsAdults

Essential HTN

(Secondary causes)

AgeAge

Frequency

Measurement of blood pressure in children

Measurement of blood pressure in children

BP measurement : cuff choiceBP measurement : cuff choice

Cuff too narrow Good-sized cuff


American Family Physician 2006; 7(9)

40%40% of the circumference of the circumferenceoror

2/32/3 of the arm lengt of the arm lengt

≥ ≥ 80%80% of the arm circumference of the arm circumference

BP measurement methodsBP measurement methods

• BP measurement in the office

• ABPM

• Self-blood pressure monitoring at home

BP measurement in the officeBP measurement in the office

• Most commonly used• Always obtain at least 3 values to diagnose

sustained hypertension• White coat hypertension:

– Innocent bystander (?)

– Adults data makes the f/u of white coat hypertension mandatory, no data in children

Single office BP measureSingle office BP measure

• Is there any difference between arm and wrist cuff?

http://www1.istockphoto.com/file_thumbview_approve/1398418/2/istockphoto_1398418_checking_blood_pressure_1.jpg

Blood pressure reactivity in adultsLausanne Study

Blood pressure reactivity in adultsLausanne Study

Single office BP measurementSingle office BP measurement

ABPMABPM

Most commonly usedmethod to confirm

HTN

Prognostic factor of “dipping”

Abnormal ABPM linkedto left ventricular

hypertrophy

Self-measurement of BP at homeSelf-measurement of BP at home

• Advantages: • Greater numbers of readings• Avoidance of the white-coat syndrome• Absence of observer bias• Increased compliance with anti-hypertensive therapy

• Reference values• Derived from population studies• In adults:

– Mean + 2 SD: 137/89 mm Hg

– 95th percentile: 135/86 mm Hg

Treatment of HTN in childrenTreatment of HTN in children

When to treat HTN in children?When to treat HTN in children?

S/D BP Measure Non-pharm. pharm. treatm.

Normal < P90 No measure none none

Pre-HTN P90-95 or f/u 6 months low salt diet none unless > 120/80 physical act. CKD or

diabetes or cardiac disease

When to treat HTN in children?When to treat HTN in children?

TA S/D Measure Non-pharm. Pharmacol ttt

Stage I HTN P95-99 f/u within diet none unless+ 5 mmHg 2 weeks physical activity organ damage

or symptomatic

Stage II HTN > P99 referral diet yes+ 5 mmHg physical activity

Pharmacologic managementPharmacologic management

• Pharmacological approach will allow to control:

– hormonal aspect of BP (IEC or ARBs)– Vascular reactivity (arterial and venous) (calcium

channel blockers or peripheral -blockers)– Cardiac output (-blockers)– SNC sympathetic activity (central -agonists)

Why to treat, does it make a difference?

Why to treat, does it make a difference?

• Outcome difficult to assess in children:

• Rare complications during childhood

• Classic complications (stroke, heart failure, blindness) occur (very) late

• Notable exception of children with CKD and HTN:

Mortality in children with CKDMortality in children with CKD

Death rate per 100,000

0

10

100

1000

10000

0-14 15-19 20-30

Age (years)

Adapted from Parekh et al, J Pediatr, 2002

Dialysis

Transplant

General Population

Black White

• CrCl< 75ml/min/1.73m 2

• HTN: >95 th % (Task Force)•Normotensive: n=1987 (52%)•Hypertensive: n=1874 (48%)

• Endpoint:

– CrClby 10 ml/min/1.73m2

– Renal replacement therapy

Non-HypertensionHypertension

% P

RO

GR

ES

SIO

N T

O E

SR

D/C

R.C

L. D

RO

P 1

0

0

20

40

60

80

100

MONTHS

0 12 24 36

P<0.001

Mitsnefes et al, J Am Soc Nephrol 2003

NAPRTCS CRI Database:NAPRTCS CRI Database:

58%

49%

Morbidity in children with CKDMorbidity in children with CKD

ConclusionsConclusions

• BP measurement must be done routinely in all children, as soon as possible, at least for the first time when the child in 3 years old, or earlier in children with associated risk factors for HTN

• The vast majority of children with HTN are asymptomatic until their BP is significantly high with potential target organ damage



• Younger children (< 10 years old) often (always) have secondary HTN

• One single abnormal BP value must always be confirmed, either at the office (first), or with ABPM and/or self-monitored blood pressure at home


• Non-pharmacologic treatment must be started in every child with HTN

• Pharmacologic treatment will be reserved for children with target organ damage or severe HTN

What we knowWhat we know

• HTN exists in infancy

• In selected cases (monogenic HTN, severe symptomatic HTN) treatment benefits are obvious

• Treatment of HTN should not only rely on mere BP readings but also on associated risk factors such as obesity, diabetes, renal failure, microalbuminuria, metabolic syndrome, family history or end-organ damage

What we do not knowWhat we do not know

• What is the best way of measuring BP in children ? (office? Self blood pressure monitoring? ABPM?)

• What is the relationship between pediatric HTN and later adult morbidity/mortality in a non selected population?

• What is the role of biomarkers such as microalbuminuria?

ReferencesReferences

• Hypertension in children. Leonard G Feld. Butterworth-Heinemann Ed. Boston, 1997;233p.

• Excellent review, short, global approach and management of the child with HTN

• Hypertension: pathophysiology, diagnosis and management. Laragh JH, Brenner BM. Raven Press, New-York, 1990, 2 volumes.

• One (the) reference in adult HTN medicine

• The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents. Pediatrics 2004;114:555-576

• Last recommendations from the AAP regarding investigation and management of HTN in children. The pediatric reference