Management of Hypertension in Children

Carlos A. Delgado, M.D.FAAPDiv. Pediatric Emergency Medicine

Emory University School of Medicine

CHOA

                                      

Enregistrement de la pression artérielle à l'aide d'un capteurintroduit dans l'aorte: première méthode historique de mesurede la pression artérielle (1732, Stephen Hales).

The Sphygmomanometer - Riva Rocci's instrument

Marey's wrist sphygmograph, c.

1857.

                           

   

                           

   

Dudgeon's wrist sphygmograph, c. 1890

The Korotkoff sounds

http://www.record-eagle.com/2005/jan/12obese.jpg

Objectives

• Recall key elements necessary for the diagnosis and management of hypertension in children.

• Discuss various pharmacological treatment options for the management of hypertensive urgencies and emergencies

Hypertension basics

Primary hypertension: • Significant health problem, with overweight/obesity

being a major contributor to much of the pre-hypertension and stage1 hypertension.

• Body mass index (BMI) should be calculated and plotted on the CDC growth curves in pediatric patients.

• The prevalence of hypertension increases with increased BMI; hypertension is present in about 30 percent of those with BMI above the 95th percentile.

Prevalence

• Estimated at 1-2 % with an increase in primary hypertension likely due to the rising trend towards childhood obesity

• Overweight prevalence is aprox 20%– 31% Hispanics – 22% African American – 15% White– 11% Asian

Prevalence of Elevated Blood Pressure

• Hispanics 25%

• African American 19.5%

• White 9.5%

• Asian 4.5%

Prevalence of Hypertension Compared to BMI

Pediatrics 113;3;475-482;March 2004

Definitions

• Hypertensive Emergency is a severely elevated blood pressure with evidence of target organ injury- most commonly the CNS system, kidneys, or cardiovascular system.

• Hypertensive Urgency is a severely elevated blood pressure with no evidence of secondary organ damage but if left untreated will imminently result in target organ injury.

                 

       

How to measure a blood pressure

• Patient resting in seated position right arm at the level of the heart.

• Blood pressure cuff: – The width of the inflatable bladder should be at least

40% of the arm circumference at a point midway between the acromion process and the olecranon

– Cuff too large BP artificially low– Cuff too small BP artificially high

• Abnormal BP should be verified by auscultation with a sphygmomanometer.

Pediatric hypertension

• 1987/2004 Task Force on Blood Pressure Control in Children – Hypertension: is the average systolic and/or diastolic blood pressure persistently above the 95th percentile.

• Severe hypertension that above the 99th percentile.

Pediatric hypertensionThe blood pressure must be obtained on three separate occasions. If the systolic and diastolic blood pressure falls into different categories, classify by the higher category.

- NORMAL BLOOD PRESSURE is defined as a systolic and diastolic blood pressure below the 90th percentile for gender, age and height percentile (utilizing the Center for Disease Control (CDC) growth curves).

-PRE-HYPERTENSION is defined as the 90th percentile to less than 95th percentile or if BP greater than 120/80 even if below the 90th percentile (up to below the 95th percentile).

- STAGE 1 HYPERTENSION is defined as a blood pressure between the 95th percentile and the 99th percentile plus 5mmHg.

-STAGE 2 HYPERTENSION is defined as a blood pressure above the 99th percentile plus 5mmHg.

-“WHITE COAT” HYPERTENSION is defined in a patient with blood pressure above the 95th percentile in the physician’s office or clinic, who is normotensive outside the clinical setting.

* 1987/2004 Task Force on Blood Pressure Control in Children

Hypertension

• Systolic BP elevation is an important factor in the morbidity of hypertension in children and adults

• Mild to moderate BP elevation is associated with increased left ventricular mass

• Elevation of systolic BP is more closely related with LV morphology

• Among hypertensive pts prevalence on LVH ranges from 30-70%

• Treatment of hypertension should be directed to normalization of systolic BP

Hypertension management

• The indications for antihypertensive drug therapy:– secondary hypertension and – insufficient response to lifestyle modification.

• Pharmacological therapy should be initiated with a single drug.

• Acceptable classes for use in children include ACE inhibitors, angiotensin receptor blockers, beta-blockers, calcium channel blockers and diuretics.

BP Goal

• The goal for antihypertensive treatment in children should be reduction of BP to below the 95th percentile unless concurrent conditions are present, in which case BP should be lowered to below the 90th percentile.

Hypertensive Emergencies

• Usually accompanied by signs of hypertensive encephalopathy and typically causing seizures.

• Should be treated with intravenous antihypertensive that can produce a controlled reduction in BP aiming to :– decrease the BP by < 25% over 1st 8 hours

and normalizing the BP over 26 to 48hrs.

Hypertensive Urgencies

• Less serious symptoms such as: – headache, – vomiting

• Can be treated by either intravenous or oral antihypertensives

Common causes of hypertension in children

Age group CauseNewborns Renal vessel thrombosis

Renal artery stenosis

Congenital renal anomalies

Coartation of the aorta

Early Childhood 1-6 yrs Renal parenchymal disease

Renovascular disease

Coartation of the aorta

School age 6- 10 yrs Renal parenchymal disease

Renovascular disease

Essential hypertension

Adolescence Essential hypertension

Renal parenchymal disease

Renovascular disease

Drugs

* Pheochromocytoma and Cushing Disease should be considered in all age groups

Clinical Assessment

• History – Prior history of HTN

• Abrupt withdrawal of meds

– Symptoms • Visual changes, CNS disturbance, renal disease,CV

compromise

• Flushing, tachycardia, weight changes,

– Umbilical vessel catheterization, GU anomalies, recent head injury, medication use, drugs of abuse

– Family history of hypertension or stroke

Physical examination

• Vital signs , pulse oximetry• 4 limb blood pressures• Accurate weight• Fundoscopic examination• Neurologic examination including mental

status• Cardiovascular examination• Renal artery bruits, edema, growth failure

Ancillary investigations

• CXR• EKG• CT head• UA and serum BUN and creatinine• CBC to r/o HUS or anemia• Renal ultrasound• Plasma renin• MRA/Duplex Doppler flow studies/3-D CT

Management

• Persistent mild to moderate BP elevation:– Close follow up with outpatient evaluation

and management.

Management

• BP should be reduced no more than 25% in the first 2 hours, then reduced gradually over the next 3-4 days.

• IV route for medication administration is preferred- better titration and predictable absorption.

                                                             

Drugs• Sodium Nitroprusside• Labetalol• Metoprolol• Nicardipine• Esmolol• Hydralazine• Fenoldopam• Nifedipine• Lisinopril• Amlodipine

Sodium Nitroprusside

• Arterial and venous vasodilator• No chronotropic or inotropic effects• Extremely short half-life• Easily titrated to effect• Dose: 0.3-0.5 micrograms/kg/min.

Maximum 8 mcg/kg/min

Most patients will respond at rates of 3 mcg/kg/min

Sodium Nitroprusside

• It’s rapid vasodilatory effects cause reflex stimulation of sympathetic nervous system resulting in tachycardia

• Long term therapy( > 24hrs) may lead to accumulation of cyanide and thiocyanate.

Fenoldopam( Corlopam®)

• Fenoldopam is a selective dopamine agonist • In both an oral and parenteral form, the drug causes

peripheral vasodilatation by stimulating dopamine-1 adrenergic receptors.

• Intravenous fenoldopam may provide advantages over sodium nitroprusside because it can induce both a diuresis and natriuresis, is not light sensitive, and is not associated with cyanide toxicity.

• There is no evidence for rebound hypertension after discontinuation of fenoldopam infusion.

Fenoldopam

• Selective dopamine agonist causing vasodilatation of the renal, coronary, cerebral and splacnic vasculature reducing MAP.

• Successful controlled hypotension in spinal fusion and in PICU

• Peak effect in 5-15 minutes• Infusion 0.1-2 g/kg/min • Side effects: reflex tachycardia, Increased ICP

and IOP

Labetalol

• Both and sympathetic blocker• May be safer that sodium nitroprusside• Reduces vascular resistance• Difficult to titrate due to long half life• Continuous infusion or bolus • Infusion- 0.2 to 3 mg/kg/hr• Intermittent bolus – 0.2- 1 mg/kg• Efficacious in those with renal disease• Caution: asthma,CHF, diabetes

Metoprolol (TOPROL-XL® )

1- selective blocker• Doses: 0.2 mg/kg "low," 1.0 mg/kg "medium,"

or 2.0 mg/kg "high")

• The most common adverse events:– Headache 11.7% – upper respiratory tract infection 6.8% – dizziness 4.2% and cough 2.5%

Esmolol ( Breviblock®)

• Ultrashort cardioselective - adrenergic blocking agent

• Primary use in the perioperative management of tachycardia and hypertension in patients at risk of developing hemodynamically-induced myocardial ischemia.

• Infusion: loading 100-500 g/kg followed by infusion of 50-300 g/kg/min

• Caution in asthmatics, bradycardia, and CHF

Nicardipine (Cardene®)

• Calcium channel blocker• Blocks movement of Ca+ across vascular smooth

muscle decreasing preventing contraction total vascular resistance.

• Advantages: Lack of decreased cardiac output and limited effects on chronotropic and inotropic effects on the heart.

• Can be given IV• Rare hypotensive episodes• Limited experience in children

Nicardipine

• Dose: 0.5 – 1 g/kg/min to max of 3 g/kg/min

• Infusion should be increased every 3-5 minutes to desired effect

• Fast onset of action• Adverse effects: increased ICP, headache

nausea, hypotension• Cimetidine increases effects

Hydralazine

• Potent arterial vasodilator to reduce systemic BP

• Onset of action is 5-30 mins

• Duration of action 4-12 hrs

• Dose: 0.1-0.5 mg/kg/dose max 20 mg every 4-6 hr

• Losing popularity

Nifedipine

• Reported adverse cardiac and neurologic sequelae due to hypotension in adults

• Reported rebound hypertension causing adverse neurologic events in children associated with the use of short acting nifedipine. Calcium channel blocker- decrease peripheral vascular resistance

• Dose 0.25mg/kg

Blaszac study J Peds 2001- no significant complications

Nifedipine

• Sublingual or orally best absorption is to bite and swallow

• Recommended oral administration to be limited to hypertensive urgencies

Lisinopril (Zestril®)

• Lisinopril is ACE inhibitor.• It is used to treat mild to severe high

blood pressure as well as congestive heart failure. Lisinopril is given as a tablet.

• Side effects– Dizziness – Rash – Dry cough

Lisinopril(Zestril®)

• For people not on diuretics, the initial starting dose is usually 10 milligrams, taken 1 time a day. The long-term dosage usually ranges from 20 to 40 milligrams a day, taken in a single dose.

• Diuretic use should, if possible, be stopped before using lisinopril.

• Renal disease needs dose adjustments, depending on kidney function

Lisinopril(Zestril®)

• Dose is 0.07 milligrams per day up to a total of 5 milligrams per day.

• Zestril is not recommended in children younger than 6 years old or in children with poor kidney function.

Amlodipine ( Norvasc® )

• Amlodipine is a calcium channel blockers. • Amlodipine - tablet to take by mouth. It is usually taken once a

day• Amlodipine may cause side effects.

– swelling of the hands, feet, ankles, or lower legs – headache – upset stomach – stomach pain – dizziness or lightheadedness – drowsiness – excessive tiredness – flushing (feeling of warmth)

Amlodipine ( Norvasc® )

• Dose: 0.05 – 0.1 mg/kg/day once daily increase to effect

• Usual target dose is 0.2-0.25 mg/kg/day

• Younger children may require 0.3-0.4 mg/kg/day

• Titrate over 1-2 week period

Diuretics

• No longer 1st line recommendation of chronic pediatric hypertension

• Furosemide

• Spirinolactone

When to refer to specialist

• Blood pressure values greater than 95% for gender , age, height on three different occasions.

• One or more risks factors of cardiovascular disease– Obesity– Diabetes– High blood lipids– Family hx. of stroke, cardiovascular disease– Failed pharmacological management

So which drugs should I use?

• Labetalol for initial bolus, it alone may control BP, may require rebolusing

• Nicardipine if placing on a drip. Use on neonates is not recommended due to immature function of sarcoplasmic reticulum.

• If using PO: Norvasc or Labetalol

•  Classification of Hypertension in Children and Adolescents With Measurement Frequency and Therapy Recommendations

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