Hypertension Clinic For Children

Systemic hypertension is an important condition in childhood, with estimated population prevalence of 1-2% in the developed countries.

The causes for increase in blood pressure are attributed to obesity, change in dietary habits, decreased physical activity and increasing stress. Similar data is lacking from India; small surveys in school children suggest a prevalence ranging from 2-5%

Normative data on blood pressure values, based on age and height percentiles, derived from a large multiethnic cohort of children in USA.

The Expert Group endorses the guidelines on definition of hypertension proposed in the Fourth US Task Force Report on Hypertension, which are in broad conformity with the Seventh Joint National Commission Report for adults

Pre-hypertension is defined as systolic or diastolic blood pressure between the 90th and 95th percentile.

Adolescents having blood pressure >120/80 mm Hg, but below the 95th percentile are also included in this category.

• Hypertension is defined as systolic or diastolic blood pressure exceeding the 95th percentile for age, gender and height, on at least three separate occasions, 1-3 weeks apart. Since the severity of hypertension influences its management, it should be staged as below.
• Stage 1 hypertension : Systolic or diastolic blood pressure values exceeding the 95thpercentile and up to 5 mm above the 99th percentile. Blood pressures in this range should be rechecked at least twice in the next 1-3 weeks, or sooner if symptomatic, before the patient is diagnosed to have sustained hypertension.
• Stage 2 hypertension : Systolic or diastolic blood pressure values 5 mm or more above the 99th percentile. The presence of stage 2 hypertension should be confirmed on a repeat measurement, at the same visit. These patients require further evaluation within one week or immediately if they are symptomatic

White coat hypertension

Some children may show blood pressure higher than the 95th percentile in clinic or hospital setting, while it is below 90th percentile in familiar environments. These patients do not need pharmacological treatment, but require blood pressure monitoring over the next 12 months, since a proportion is at risk of sustained essential hypertension.

Screening for hypertension

The Group recommends annual measurement of blood pressure in all children more than 3-year-old, who are seen in clinics or hospital settings. Blood pressure should also be measured in at-risk younger children with:

• history of prematurity, very low birth weight or interventions in NICU;
• congenital heart disease;
• recurrent urinary tract infections,known renal or urological diseases hematuria or proteinuria;
• family history of congenital renal disorders;
• malignancy, post organ transplant;
• conditions associated with hypertension,
  e.g.,neurofibromatosis, tuberous sclerosis and ambiguous genitalia. Blood pressure should be measured in patients who present with features of kidney or heart disease, seizures, altered sensorium and headache or visual complaints

Transient hypertension

Hypertension may be transient in certain conditions, e.g., acute glomerulonephritis, acute intermittent porphyria, Guillain Barre syndrome, raised intracranial pressure, corticosteroid administration, anxiety and hyperthyroidism.

Therapy for hypertension may be required in some cases. Persistence of elevated blood pressures requires detailed evaluation.

Causes of Persistent Hypertension

Renal parenchymal disease :

Chronic glomerulonephritis,
Reflux nephropathy, obstructive uropathy,
Polycystic kidney disease, renal dysplasia

Renovascular hypertension :

Idiopathic aortoarteritis (Takayasu disease),
Renal artery stenosis,
Renal arteryThrombosis

Cardiovascular disease :

Coarctation of aorta

Primary (essential) hypertension

Endocrine :
Pheochromocytoma,
Cushing syndrome,
Congenital adrenal hyperplasia,
Primary hyperaldosteronism,
Liddle’s syndrome,
Syndrome of apparent mineralocorticoid excess,
Glucocorticoid remediable aldosteronism,
Neuroblastoma

Renal tumors :
Wilms’ tumor,
Nephroblastoma

Clinical Features Indicating Underlying Diagnosis

Underlying cause	Feature
Renal parenchymal	Facial puffiness, edema, abdominal pain, dysuria, hematuria, frequency, polyuria;
urological	history of urinary tract infections; abdominal mass
Renovascular	Asymmetric pulses, abdominal/neck bruit, weak femoral artery pulses, café au lait spots
coarctation of aorta	neurofibromatosis
Connective tissue disease	Arthritis, arthralgias, unexplained fever, polymorphic rash
Endocrine	Muscle weakness, cramps; episodic fever, pallor, sweating, flushing, tachycardia; polyuria, polydipsia, failure to thrive; abdominal mass; ambiguous genitalia / virilization

Basic Diagnostic Work Up :

1)  Evaluation for cause
Hemogram
Blood urea, creatinine, electrolytes
Fasting lipids, glucose, uric acid
Urinalysis, culture
24-hr urinary protein or spot protein to creatinine ratio
Chest X-ray
Renal ultrasonography

2)  Screen for target organ damage
Retinal fundus examination
Urine: microalbumin, spot protein to creatinine ratio
Chest X-ray, ECG, echocardiography

Additional Diagnostic Tests for Sustained Hypertension

Condition	Diagnostic investigations
Glomerulonephritis	Complement (C3), ANA, ANCA, anti-dsDNA, renal biopsy
Reflux nephropathy	Micturating cystourethrogram, DMSA scintigraphy
Renovascular hypertension	Doppler flow studies, captopril renography Angiography (MR, spiral CT, digital subtraction or conventional) Renal vein renin activity
Coarctation of aorta	Echocardiography, angiography
Endocrine causes	Thyroxine, thyroid stimulating hormone Plasma renin activity, aldosterone Plasma and urinary cortisol Plasma and urine catecholamines; MIBG scan, CT/MR imaging

Management

It is useful to distinguish essential from secondary hypertension. While the initial management for patients with essential hypertension comprises of life style modifications, most patients with sustained secondary hypertension require treatment with antihypertensive agents

Patients are primarily managed by lifestyle modifications and revaluated 6 months later. The parents of these children are informed and advised regarding careful follow up. Medications are not required unless the patient has comorbid conditions or evidence of target organ damage.

Essential hypertension

Patients with essential hypertension are initially managed with lifestyle modifications.

Pharmacological therapy is initiated if there is

• a comorbid condition (chronic kidney disease, diabetes mellitus or dyslipidemia),
• Target organ damage or
• Failure of blood pressure to decline below the 95th percentile, despite lifestyle modifications, for 6 months.

Lifestyle modifications

Lifestyle changes are recommended for all children with hypertension; interventions based on daily routines are likely to be more successful.

Weight reduction

Achievement of ideal body weight is important, since reduction of weight reduces sensitivity of blood pressure to salt and attenuates cardiovascular risk factors, e.g., dyslipidemia and insulin resistance. Reduction of BMI by 10% is reported to lead to 8-12 mm Hg fall in systemic blood pressure. Weight reduction should be achieved by regular physical activity and diet modification. Prevention of excess weight gain limits future increases in blood pressure.

Increased physical activity

Children are encouraged to be active not only for weight control but for their well being. While they often find defined physical exercises (aerobics, tread mills) boring, they are likely to continue activities incorporated into their routines, e.g., walking or cycling to school, playing with friends outdoors and swimming.

The Group supports the recommendations of :

• 30-60 minutes or more of physical activity every day
• Adolescent girls in our country should be specifically targeted, since they spend considerably less time than boys in outdoor sport.

Sports avoided :

Participation in competitive sports is avoided in patients with stage 2 hypertension or target organ damage, until blood pressure is controlled satisfactorily.

Strength training (isometric) exercises (e.g., weight lifting, gymnastics, karate and judo) should be avoided.

Dietary changes

The effect of diet on blood pressure in children is extrapolated chiefly from studies on adults.

Salt intake :

• Recommendations for daily sodium intake in children range between 1-1.5 g (45-65 mEq sodium, 2.6-3.8 g salt). Dietary sodium restriction is associated with small reductions in blood pressure in children.
• A ‘no added salt diet’ is a satisfactory approach to restrict salt intake.
• Intake of food products high in sodium (processed and canned foods, items prepared in fast food shops including pizzas, pickles and salted potato chips) should be avoided.
• Increased potassium intake, through vegetables and fruits, is associated with modest reduction of systolic and diastolic blood pressure in adults with essential hypertension
• Potassium intake should however be restricted in children with chronic kidney disease with glomerular filtration rate (GFR) below 30 mL/ min/1.73 m2, adrenal insufficiency, severe heart failure, or those receiving treatment with angiotensin converting enzyme inhibitors (ACEI non-steroidal anti-inflammmatory agents and potassium sparing diuretics.

Despite suggestions that foods rich in calcium, magnesium, folic acid and fiber are useful in reducing blood pressure, there is limited evidence in this regard.

An increased intake of fresh vegetables and fruits, whole grains and non-fat dairy is recommended. These foods are low in sodium and saturated fat and rich in minerals (potassium, calcium, magnesium) and fiber.

THALI :

The Group endorses the dietary recommendations of the IAP Consensus Committee on Obesity.
The dailyfood composition is considered a 'thali', where half
(50%) is vegetables, salads and fruits,
(25%) is cereals (rice and/or chapattis), and the
remainder is protein based (legumes, milk, egg,animal protein).

The intake of fried foods, snacks and sweet dishes should be limited

Secondary hypertension

Patients with sustained secondary hypertension require therapy with antihypertensive agents. Physicians should be aware of the risk of hypertensive emergencies in children with stage 2 hypertension. The need to adhere to healthy eating habits and lifestyle is emphasized.

Drug therapy

Drug therapy is indicated in patients with

• acute or chronic complications of hypertension,including evidence of target organ damage,
• secondary hypertension,
• stage 2 hypertension,
• stage 1 hypertension that persists despite 6-months’ of lifestyle modifications, and
• prehypertension or stage 1 hypertension with comorbid conditions (diabetes, chronic kidney disease or dyslipidemia).

Principles of treatment

• The goal for treatment is reduction of blood pressure to levels <95th percentile, unless comorbid conditions or target-organ damage is present, when it should be lowered to <90th percentile.
• Commonly used medications in children include ACEI, calcium channel blockers, Beta blocker etc.

Hypertensive emergencies

Patients with stage 2 hypertension may present with acute, life threatening target organ damage involving central nervous system (encephalopathy, seizures), heart (pulmonary edema) or kidneys (acute renal failure).

These patients need hospitalization for monitoring and supportive care. Blood pressure levels are usually 5-15 mm above the 99th percentile, and should be reduced to safe levels.

Rapid reduction of blood pressure might, however, compromise blood flow and result in ischemic complications in the brain, retina, spinal cord and kidneys. Blood pressure reduction, therefore, must be regulated in order to prevent end organ damage to these organs

The difference between the observed and desired (95th percentile) blood pressure is estimated; 25-30% of the desired reduction should occur in the first 3-4 hr, another 25-30% in the next 24 hr, and then to the desired level over next 2 days. Agents of choice include short acting, intravenous (IV) preparations that are titrated to response (sodium nitroprusside, nitroglycerine, labetalol and nicardipine)