Hypertension In Childhood

Anita Khalil

Hypertension in infancy and childhood is rare, though it is now a recognised concept that roots of essential hypertension extend back into childhood, with persistence of rank order with age, a concept known as "Tracking". The diagnosis of hypertension can only be made after confirmation of 3 successive measurements of blood pressure(B.P) performed at 3 different consecutive examinations. The real prevalence of hypertension in children is therefore much lower than 5% and could be about 1%.

Hypertension in children is often due to an identifiable aetiology, predominantly renal or vascular disease. But recent studies have inferred that because of more frequent routine blood presssure recordings in children, mild essential or primary hypertension is being increasingly diagnosed and is now considered to be the commonest cause of hypertension in children.

Clinically hypertension has been classified as:

Medical Management Of Hypertension In Children

Drug therapy in hypertension is always a challenging task, more so in children where the causes are so variable, where renal disorders(75%) and renovascular(15%) disorders accounting for nearly 90% of childhood hypertension.

1. If a child has been found to be hypertensive on 3 successive readings adequate investigative work up is urgently required to arrive at a diagnosis (Table 1).
   
   Definition of Hypertension by age group (1996)

   Age Group	Blood Pressure
   New born-Term	95/56
   Preterm	86/56
   1 month - 1 year	96/58
   1 year – 3 years	102/66
   3 years – 5 years	115/75
   6 years – 9 years	122/78
   10 years – 12 years	126/82

   
   
2. Some precipitating causes eg. Drugs or toxins(lead) have to be excluded.
3. After fully investigating - if the underlying cause is either coarctation of aorta, pheochromocytoma or some renovascular condition - then adequate measures should be taken to remove the cause, surgically or by intervention.
4. Risk factors : before starting drug therapy, it is essential to consider the presence of risk factors in an individual such as obesity, lack of exercise, feeding habits, family history of hypertension.
5. Non pharmacological measures - change in life style for 3 - 6 months
   1. optimum aerobic / non aerobic exercises
   2. weight reduction, (<5-6gm/day)
   3. diet - salt restricted, low calorie high fibre carbohydrarate diet with potassium supplements.
   4. Avoidance of tobacco, alcohol or any narcotic drugs in adolescents.
6. Pharmacological therapy: Drugs are started if the B.P. does not respond to non pharmacological measures for 6 months, then different groups of antihypertensive drugs are started. These drugs are adrenergic (b) blockers, diuretics, vasodiolators, calcium channel blockers and angiotensin converting enzyme inhibitors (ACE inhibitors). Stepped care approach is advocated to treat childhood hypertesion (Table II).
   
   
7. Hypertensive Crisis: In hypertensive emergency - there is an imminent danger of occurrence of target organ damage such as encephalopathy, left ventricular failure, intracranial failure or acute renal failure. This situation has to be treated urgently to bring the B.P. down but with adequate monitoring so that under perfusion or any other complication does not occur. The drugs used are given in Table III.
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   Anti Hypertensive Drugs And Dosage

   Agent	Action	Dose	Side Effects	Comments
   Diuretic Thiazides		mg/kg/dose1-2 mg oral	hypokalemia hyperurecemia	mild HT
   Furesemide (lasix)	Loopdiuretic	IV-1-2mgoral 2mg	hypokalemia alkalosis	diuretic of choice in all condition
   Spironolactone (aldactone)	K+sparing aldosterone antagonist	1-3 mg	gynaecomastia amenorrhoea hyperkalemia	diuretic of choice of mineralocorticod excess state
   Triamterene (Dyatide)	K+sparing			mild HT
   Adrenergic BlockersÑ blocker Phentolamine	Ñ rec. -blocker	IV-0.1 mgmax.5mg	Reflex tachycardia nasal stiffness	Drug of choice in pheochromocytoma
   Phenoxy benzamine	do	2-5 mg/day	Postural hypotension	Pheochromocytoma
   Prazosin	Ñ rec.-blocker	Oral1-5 mg/day		Initial dose at bed time
   Ò blocker Propanolol	lower renin	oral 0.25-1. mg	Bronchospasm bradycardia hallycination	Mild-mod hypertension Hyperthyroid dism
   Atenolol	CardopselectiveÒ blocker	oral 1-2mg
   Ñ - 1 and Ò blocker Labetolol	Ñ + Ò blocker	IV-0.25-1mg	Hypotension Headache, CHF bronchospasm	HypertensiveCrisis
   Vasodilator Hydralazine	Arterial dialator	0.5-2mg max.200mg IV-0.4-0.8mg	Postural Hypotension
   Diazoxide		IV-2-5mg Max.100mg	hypotension	Hypertensive crisis
   Calcium Channel blocker Nifedipine		Oral 0.23-0.5mg Max.10mg	Flushing Tachycardia headache	In HT emergency -Sublingual
   ACE Inhibitors Captopril	Arterial & venous dialator	Oral 0.1-0.3mg max.2mg	Neutropenia Rash, altered taste, proteinurea, cough	Contraindicated in bil.renal art. Stenosis & seve re renal insufficiency
   Enalapril	do	IV-0.005-0.01mgOral 0.01mg	Hypotension-cough

   
   
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8. Essential Hypertension: Mild essential hypertension is being diagnosed more frequently in adolescents because of frequent B.P. measurements. It has been established beyond doubt that essential hypertension in adulthood has its origin in childhood. There are a number of risk factors associated (e.g.) obesity and lack of exercise with deranged lipid profile (e.g.) elevated total cholesterol and LDL cholesterol and decreased HDL cholesterol.