OBJECTIVES

Identify children and adolescents for whom

hypertension screening is appropriate

Implement an initial workup for pediatric

hypertension

Develop treatment plans for children with

essential or secondary hypertension

Hypertensive children

Usually asymptomatic

HOWEVER already manifest evidence of target organ damage

Left ventricular hypertrophy ( up to 40%)

Increased carotid intima-media thickness

Children with BP > 90th percentile have a 2.4-fold greater risk having hypertension as adults

BACKGROUND

Systemic hypertension is uncommon (<1%)

If present often indicative of an underlying disease process

SEVERE and SYMPTOMATIC HYPERTENSION in children is usually due to SECONDARY HYPERTENSION

Prevalence of primary essential hypertension has increased, mostly in older school age and adolescents

PREVALENCE OF HYPERTENSION IN CHILDREN

Hypertension is defined as average SBP and/or

diastolic BP that is 95th percentile for gender , age and height on 3 or more occasions.

DEFINITION

Normal Blood Pressure : < 90th percentile for age,

gender and height.

Pre-hypertension : SBP and/or DBP >90th percentile but less than 95th percentile for age, gender and height.

For age >12years, BP >120/80 regardless of 90th percentile considered pre-hypertension

Hypertension : SBP and/or DBP >95th percentile for age, gender and height

Stage 1: 95th – 99th percentile + 5 mmHg Stage 2: > 99th percentile + 5 mmHg

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CLASSIFICATION OF HYPERTENSION

Hypertensive urgency:

Significant elevation in BP without accompanying end-organ damage; more common in children.

(180 or higher for your systolic pressure or 110 or higher for your diastolic pressure)

Symptoms include headache, blurred vision, and nausea

Hypertensive emergency: Elevation of both systolic and diastolic BP

(exceeding 180 systolic or 120 diastolic)

with acute end-organ damage (e.g., cerebral infarction or hemorrhage, pulmonary edema, renal failure, hypertensive encephalopathy, or seizures)

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HYPERTENSIVE CRISIS

Short term mechanisms

Baroreceptors (low pressure & high pressure)

Hormonal

Noradrenaline-adrenaline system

Renin-angiotensin-aldosterone system

Vasopressin system

Long term mechanisms

Renal body fluid pressure control system

BLOOD PRESSURE REGULATIONS

BARORECEPTOR REFLEX CONTROL

How should blood pressure be

measured in children?

The child should be calm and free of anxiety The child should have been sitting quietly for 5 minutes.

The child should be sitting with back supported, both feet on the floor and right cubital fossa supported at heart level.

Choose the appropriate cuff size: The cuff width should cover ~70% of the distance

between the acromion and the olecranon . The cuff bladder length should be 80 to 100% of the arm

circumference, and the cuff bladder width should be at least 40% of the arm circumference at the midpoint of the acromion-olecranon distance.

Choose the appropriate size cuff

Recommended Dimensions for Blood Pressure Cuff Bladders

Maximum Arm

Age Range Width (cm) Length (cm) Circumference (cm)*

Newborn 4 8 10

Infant 6 12 15

Child 9 18 22

Small adult 10 24 26

Adult 13 30 34

Large adult 16 38 44

Thigh 20 42 52

*Calculated so that the largest arm would still allow the bladder to encircle the arm by at least 80 percent.

METHODSPalpatory Method BP recording is 10 mm Hg less

than that obtained by auscultatory method .

Auscultatory Method Preferred method. BP tables are based on it.

Doppler Study Non invasive procedure

Oscillometric Method Better to record mean BP. Useful in infants and young children. BP > 90th percentile should be rechecked by auscultatory method.

Flush Method Used in newborns. Only SBP can be recorded.

Ambulatory Blood Pressure Monitoring

White-coat hypertension Target-organ injury risk

BP should be recorded in all 4 limbs.

Cuff should not be applied too tight (low BP recording) or too loose (high BP recording).

BP monitoring subsequently should be taken in the same limb and position.

Normally the BP is 10-20mm Hg higher in lower limbs compared to the upper limbs.

POINTS TO BE REMEMBERED

COMMONEST CAUSES

Newborn Umbilical artery catheterization and

Renal artery thrombosis.

Childhood Renal disease, COA, endocrine

disorders or medications.

Adolescents. Essential hypertension becomes

increasingly common.

ETIOLOGY

DEVELOPING A DIFFERENTIAL . . . “M.O.N.S.T.E.R.”: A simple pneumonic to start the thinking process

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Renal Causes Renal Parenchymal diseases (78%)

Renal vascular diseases (12%)

Cardiovascular CoA(2%)

Condition with large stroke volume (PDA, AV fistula)

Endocrine Hyperthyroidism

Excessive Catecholamine levels (Pheochromocytoma)

Adrenal dysfunction (CAH 11b, 17 a hydroxylase deficiency)

Hyperaldosteronism (Conn's Syndrome, Renin Producing Tumors)

Hyperparathyroidism

Neurogenic Raised ICT, Poliomyelitis,GBS, encephalitis

Drugs and Chemical Sympathomimetic drugs , Amphetamines, Steroids, OCP, Heavy matal poising (Hg, Lead), Cocaine, Cyclosporine

Miscellaneous Hypercalcemia, After Coarctation repair, fractures of long bone,Pre eclampsia etc.

CAUSES OF HYPERTENSION IN PEDIATRIC POPULATION

Obesity-- for each one unit increase in BMIz-score, children 8 to 17 years of age have been shown tohave twice the risk of having a BP greater than the 95thpercentile.1

Usually asymptomatic

Mild to moderate obesity

Clinical manifestation of the underlying disease

Headache, dizziness, epistaxis, anorexia, visual changes, seizures

Hypertensive encephalopathy : vomiting, temperature elevation, ataxia, stupor, seizures

CLINICAL MANIFESTATIONS

Acute Gromerulonephritis Oliguria, haematuria, mild proteinuria, oedema

Pyelonephritis Urinary tract infection, fever

Haemolytic UraemicSyndrome

AGE (bloody stool), weakness, irritability, oliguria, oedema

Henoch-Schonlein purpura Palpable purpuric rash, abdominal pain, haematochezia, periarticular swelling, scalp & scrotal oedema, haematuria

SLE Arthritis, arthralgia, weight loss, fever, malaise, malar rash, alopecia, oral ulcers, haematuria

Renal vein thrombosis Abdominal pain, history of umbilical catheterization

Familial nephritis Frequent haematuria

Wilms tumour Abdominal mass, abd pain, fever, microscopic/gross haematuria

Neuroblastoma Abdominal mass, fever, weight loss, limp, back pain

Neufibromatosis Skin nodules, family history

Hyperthyroidism Tremor, anxiety, sweating, heat intolerance, inability to concentrate, weight loss, hyperactivity, neck mass

Pheochromocytoma Anxiety, tremor, sweating, headache, flushing, nausea, vomiting, weight loss, constipation/diarrhoea, Raynaud’s, chest pain, polyuria/nocturia

Cushing syndrome Obesity, failure of long. growth, hirsutism, weakness, acne, hyperpigmentation, history of taking steroid

Congenital adrenal hyperplasia

Ambiguous genitalia, virilization, precociouspuberty

Complete blood count : anaemia(chronic renal disease)

BUSE, Creatinine: Renal disease, hyperaldosteronism (hyperkalemia)

Urinalysis : proteinuria, haematuria

24 hr urinary protein or spot albumin to creatinine ratio

Urine culture& sensitivity: chronic pyelonephritis

Chest radiograph : CoA

Electrocardiogram : cardiac cause of HPT

Ultrasonography for kidneys , adrenals : hydroneprosis, PKD, Wilm’s tumour

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SCREENING INVESTIGATION

Aims;Assessment for target organ damageAssessment for aetiologyAssessment for other cardiovascular risk factors

Retinal fundus examination

Urine spot protein to creatinine ratio

Echocardiography : LVH, LV function

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SCREENING FOR TARGET ORGAN

DAMAGE

Renin level : plasma renin (high-renovascular; low-

hyperaldosteronism)

Toxicology screen

Thyroid and adrenal testing :T3 T4, plasma aldosterone, plasma catecholamines (pheochoromocytoma, neuroblastoma)

Urine catecholamines

Abdominal ultrasound : : Structure anomalies of kidney, renal vasculature and tumours; renal scarring, renal asymmetry(r. dysplasia, r. artery stenosis), extrarenal masses (neuroblastoma, Wilms tumour)

Renal Doppler ultrasound

Brain CT scan

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CONSIDER

NON PHARMACOLOGICAL Recommended in all children with prehypertension and

hypertension Weight management: reduction in obese children and

maintenance in normal weight Lifestyle modifications Diet modification (reduce salt intake, low fat diet).

Note that those with severe HTN should avoid very strenuous exercises including weight lifting and high intensity sports, until evaluations clears an individual for participation Some exercises can result in a brisk increase in BP that may

result in significant adverse consequences

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Management

Reduction of BP to < 95th percentile without any

concurrent conditions .

Reduction of BP to <90th percentile with concurrent conditions (eg.Hyperlipidemia ,End organ damage, Obesity, CKD Complications etc)

GOALS OF ANTIHYPERTENSIVE

THERAPY

Pharmacologic1. Hypertension but asymptomatic :

Bed rest. Re-check BP ½ hour later. Monitor BP hourly x 4 hours then 4 hourly until stable. Oral nifedipine 0.25-0.5mg/kg if necessary 4 hourly basis. Consider regular oral nifedipine (6-8 hourly) if BP

persistently high. Add frusemide 1mg/kg/dose if BP still not well controlled. Other anti-hypertensive if BP still not well controlled : Captopril 0.1-0.5 mg/kg 8 hourly. Metoprolol 1-4 mg/kg 12 hourly

2.Long standing/poorly controlled hypertension:

Combination of antihypertensives.

Different sites or mechanism of action.

Compliance.

COMBINATION THERAPY

SYNERGISTIC COMBINATIONS.

Drugs increasing renin

activity+ Drugs decreasing

renin activity

ACE inhibitors , Diuretics

+

b blockers

Sympathic inhibitors and

vasodilators cause fluid

retention. Add diuretics

b blockers + Thiazide,

Lasix ( furosemide)

ACE inhibitors + Diuretics Enalapril (Envas) +

Thiazide, Lasix

a Blocker + b blocker Prazosin + Propranolol

a or b blocker + clonidine (antagonism)

b blocker + CCB (marked bradycardia/ AV block).

Any 2 drugs of same class.

COMBINATIONS TO BE AVOIDED

Severe symptomatic hypertension with BP well above

99th percentile .

Hypertensive emergencies(encepalopathy,chf)

controlled reduction in BP

25% in first 8hrs

then gradually normalising BP 75% within 48 hours. .

Hypertensive crisis

Nifedipine0.25-0.5 mg/kg/dose oral.May be repeated twice if no response.

Sodium nitroprussideNeed to be given in ICU setting.0.5-1.0 mcg/kg/min IV infusion.May be increased to 8.0 mcg/kg/min maximum.Caution in renal and liver failure.

Labetolol0.2-1.0 mg/kg/dose repeated IV boluses0.25-2.0 mg/kg/hour IV infusion

Hydralazine0.2-0.4 mg/kg/dose IV bolus.May be repeated twice if no response.

EMERGENCIES

SECONDARY HYPERTENSION

Treatment should be aimed at removing the cause of hypertension whenever possible.

Curable forms of Hypertension

Renal Unilateral kidney disease (Nephritis,

Pyelonephritis, hydronephrosis)

Cardiovascular CoA, Renal artery stenosis, thrombosis.

Adrenal Pheochromocytoma, Neuroblastoma,

hyperaldosteronism

Miscellaneous Drugs/ OCP etc.

Management Algorithm of Systemic Hypertension