Hypertension In Children

HypertensionIn

Children

October, 2003

What are we doing here?

1. The Whys and Whats of hypertension.

Importance, epidemiology, definition.

2. The Hows of testing.

Technique, cuff size.

3. The Evaluation.

Coexisting disease, sustained, organ damage,

curable, benefit from tx, acute vs chronic?

4. The Treatment.

Meds, lifestyle

The Whys and Whats

Sustained elevated blood pressures associated with LVH, and chronic macro and micro-vascular injury – kidneys, brain, heart, peripheral vasculature.

Acute elevations associated with encephalopathy, renal dysfunction/failure, CHF, stroke in otherwise healthy organs.

Effects of Hypertension

Prevalence

1 - 3% of children have hypertension

increases in adolescents

9 - 30 % of adults (and maybe 90%

eventually?)

Blood Pressure Standards

1996 Update on the 1987 task force report on

high blood pressure in children and

adolescents

Standard tables based on age, sex, and height

Pediatrics 88(4):649-658, 1996

Interpretation of Blood Pressure

Normal < 90 %tile

High Normal 90 - 95 %tile

Hypertension > 95 %tile

Classification of Hypertension

Significant 95 - 99 %tile

–no acute target organ injury

Severe > 99 %tile

Blood Pressure Guestimates – 95th percentile Blood

Pressures for a 50th percentile Child

Systolic BP at 1 to 17 years = 100 + (age in years x 2)

Diastolic BP at 1 to 10 years = 60 + (age in years x 2)

Diastolic BP at 11 to 17 years = 70 + (age in years)

Somu et al Arch Dis Child 2003; 88:302

Severe Hypertension (99th percentile) – add 8

With two caveats:

Is it chronic or acute?

Is there acute or chronic end organ damage?

As always, you treat the patient and not the number.

The Hows of Testing

The Right Cuff Bladder width 40% of

arm circumference

measured midway

between olecranon

and acromion

Cuff should cover 80-

100% of upper arm

circumference

Standard Position

Patient seated 3-5 minutes rest Right arm supported Brachial artery at heart

level

Thigh BP

Supine

Cuff guidelines as for

arm

Korotkoff Sounds

K4 muffling

K5 disappearance

Age limitations

Evaluation

Sustained, coexisting disease, organ damage, curable, benefit from tx, acute or chronic?

take your time to evaluate if hx and physical do not suggest an acute, escalating problem

repeated bp checks with appropriate cuff in office or at home

consider abpm

Sustained?

Patient ROS

abdominal pain, dysuria, frequency, nocturia, enuresis, cola colored urine, polyuria (intrinsic renal)

joint pain or swelling, fatigue, rash, Raynaud’s (autoimmune)

headaches, dizziness, epistaxis, visual problems weight loss, sweating, pallor, fever, palpitations

(catecholamine secreting tumor, thyroid) muscle cramps, weakness, constipation

(hyperaldosteronism with hypokalemia)

PMH/Social Hx

Umbilical artery catheter Substance abuse - steroids, cocaine Medications - steroids, amphetamines,

sympathomimetics, oral contraceptives, calcineurin inhibitors, NSAIDS

Herbals – ma huang/ephedra

Family History

hypertension myocardial infarction cerebrovascular disease diabetes mellitus hyperlipidemia pheochromocytoma polycystic kidney disease

Physical Examination

general pallor and edema (renal disease) low leg pressures & high arm pressures (coarctation

of the aorta) bruits (renovascular disease or arteritis) café-au-lait spots or neurofibromas

(neurofibromatosis) moon facies, buffalo hump (Cushing syndrome)

Physical Examination - 2

Bell palsy, neurologic deficits

fundi with a-v nicking, arteriolar narrowing, flame

lesions

features of Turner syndrome

features of Williams syndrome

Etiology: Newborn Renal artery thrombosis

Renal artery stenosis

Renal vein thrombosis

Congenital renal abnormalities

Coarctation of the aorta

Bronchopulmonary dysplasia

Etiology: 1 to 6 years

Renal parenchymal diseases

Coarctation of the aorta

Renal artery stenosis

Etiology: 6 to 10 years

Renal artery stenosis

Renal parenchymal disease

Essential hypertension

Etiology: Adolescence

Essential hypertension

Obesity

Renal parenchymal disease

Renal artery stenosis

Renal Causes of Secondary HTN in Children

Nephropathy

Renal Malformation

Obstructive

Nephropathy

Pyelonephritis

Segmental

hypoplasia

Renovascular

Wilms’ Tumor

Trauma

Metabolic

(cystinosis,

oxalosis)

CV Causes of Secondary HTN in Children Aortic Coarctation

Patent Ductus Arteriosus

Renal Artery Stenosis

Arteriovenous Fistula

Aortic Insufficiency

Polycythemia

Takayasu’s Arteritis

Endocrine Causes of Secondary HTN in Children Obesity

Pheochromocytoma

Hyperthyroidism

Congenital Adrenal Hyperplasia

17-hydroxylase Deficiency

Primary Hyperaldosteronism

Cushing’s Syndrome

Causes of Secondary HTN in Children

Neurogenic Tumors Neurofibromatosis Neuroblastoma

Central Nervous System Increased Intracranial Pressure Dysautonomia

Causes of Secondary HTN in Children

Drug Exposure Sympathomimetic agents Glucocorticoids Fracture immobilization Scoliosis repair Burns Heavy metal exposure (lead, cadmium) Scorpion bites

Tailor Evaluation

History and Physical Examination

Age of patient

Severity of disease

Evaluation: High Normal

Family History Social History

– tobacco use

– drugs Examination

– weight

– target organ injury

Evaluation: Phase I

Serum electrolytes

BUN and creatinine

Urinalysis and culture

Echocardiography

+ Hematocrit, plasma lipids

+ Renal ultrasound with doppler

Evaluation: Phase II

plasma renin/aldo

catecholamines

– 24 hour urine

– plasma

Evaluation: Phase III

Directed by history, physical and prior

studies

VCUG, DMSA

Renal biopsy for nephropathy

CT or MRI for tumor

Evaluation: Phase III continued

steroid suppression/stimulation

adrenal scintigraphy/MIBG

renal angiography for renal artery

stenosis

Reasons to consider arteriogram

Severe resistant hypertension without other etiology

Increased PRA with normal noninvasive tests

Bruit

Solitary kidney with severe hypertension

Renal ArteriographyTrachtman et al, P. Neph 14:816-819

Abnormal Normal(N=12) (N=16)

Age 11.8 11.5

Sex (M:F) 6:6 6:10

Race (W:B:O) 5:5:2 9:6:1

Duration (mo) 12.1 9.8

Peak BP 182/113 175/102

Creatinine 1.1 1.0

Prior Rx 4 5

Abnormal imaging studies

Renal US 5/9 1/9

Renal scan 2/3 2/3

Chronic TherapyNon-pharmacologic

Primary hypertension

– weight control

– exercise

– stress reduction

– dietary (salt and calories)

– elimination of contributory medications

– smoking cessation

Chronic TherapyPharmacologic

Diuretics Beta-adrenergic blockers Angiotensin converting enzyme inhibitors ARB’s Calcium channel blockers Vasodilators Alpha-1-adrenergic blockers Alpha-2-agonists Selective aldosterone antagonists (Eplerenone) Dopamine-1 agonist (Fenoldopam)

Diuretics Concerns

– Lipid disorders Contraindications

– salt wasting nephropathy– athletes in hot weather

Reserve for those with Renal Disease Thiazide - GFR 50 - 100 % Furosemide - GFR < 50% Aldactone - Hyperaldosterone states

– Nephrotic syndrome, CHF, Liver failure

Beta-blockers Concerns

– Hyperlipidemia– Asthma– Cardiovascular effects

Cardioselective – Atenolol– Metoprolol

Non-selective– Propranolol

Angiotensin Converting Enzyme Inhibitors Cautions

– Renal Artery Stenosis– Solitary Kidney– Renal Failure– Infants – Hyperkalemia– Cough– Angioedema

Calcium Channel Blockers

Short acting v. Long acting

Action: dilate peripheral arterioles by

blocking calcium transit

Nifedipine

Amlodipine

Felodipine

(Verapamil, Diltiazem)

Vasodilators Side effects

– Tachycardia

– Water retention

Hydralazine

Minoxidil

Diazoxide

Sodium Nitroprusside

Alpha-1-Adrenergic Blockers

Side effect first dose hypotension

Modest potency

Prazosin/doxazocin

Phenoxybenzamine/phentolamine

pheochromocytoma

Central Alpha-2-Agonists Side effects

– Somnolence

– Rebound hypertension Indications

– Attention Deficit Disorder Clonidine Methyldopa Guanabenz

Combination action

Labetalol – alpha (weak) and beta (non selective)

po or iv

lipids unchanged

Antihypertensives in NewbornsDiazoxide iv Initial: 1-2 mg/kg/dose

Max: 5 mg/kg/dose q 2-6 hrs prnNitroprusside iv Initial: 0.25-0.5 mch/kg/min,

double q 15-30 minHydralazine iv, po Initial: 0.1-0.5 mg/kg/dose q 3-6 hrs

Max: 2 mg/kg/dose q 6 h (po 2x iv dose)Propranolol iv,po Initial: po 0.25 mg/kg/dose q 6-8 hrs

Max: po 1-4 mg/kg/dose q 6-8 hrsInitial: iv 0.01-0.15 mg/kg/dose q 6 hrsMax: iv 4 mg/kg/dose q 6 hrs

Captopril po Initial: 0.01 mg/kg/dose q 6 hrsMax: 0.1-1.0 mg/kg/dose q 6 hrs

Hypertensive EmergenciesNicardipine 1-3 mcg/kg/min iv

Labetalol 1-3 mg/kg/hr iv

Esmolol Load 500 mcg/kg, then 50-250 mcg/kg/min

Nitroprusside0.5-0.8 mcg/kg/min iv

Enalapril 5-10 mcg/kg/dose iv q 6-12 hrs

Diazoxide 1-2 mg/kg/dose iv q 10-15 min

Phentolamine0.1-0.2 mg/kg/iv (pheo)

Nifedipine 0.25-0.5 mg/kg po (max dose 20 mg)

Hydralazine 0.1-0.5 mg/kg iv ( max dose 25 mg)

Propranolol 0.01-0.05 mg/kg iv over 1 hr (max 10 mg)

Lasix 1-4 mg/kg iv

Fenoldopam 0.1 – 0.8 mcg/kg/min