CHRONIC SUSTAINED HYPERTENSION
DEFINITION:
Systolic and diastolic blood pressures at or above the 90th
percentile for age and sex.
EPIDEMIOLOGY:
- incidence: 0.81% (neonatal)
- age of onset:
- risk factors:
- family history of essential hypertension
- Neonatal Hypertension:
- umbilical arterial catheter (UAC) - 8.8% with UAC become
hypertensive
- Bronchopulmonary Dysplasia (BPD) - 5.9% with BPD become
hypertensive
- Patent Ductus Arteriosus (PDA) - 3.1% with PDA become
hypertensive
- Intraventricular Hemorrhage (IVH) - 2.9% with IVH become
hypertensive
DIFFERENTIAL DIAGNOSIS FOR CHRONIC SUSTAINED HYPERTENSION:
- Renal Artery Thrombosis
- Renal Artery Stenosis
- congenital renal malformations
- Coarctation of the Aorta
- Bronchopulmonary Dysplasia
2. Infancy - 6 years
- renal parenchymal diseases*
- Coarctation of the Aorta
- Renal Artery Stenosis
3. 6 - 10 years
- Renal Artery Stenosis
- renal parenchymal diseases
- Primary Hypertension
4. Adolescence
- Primary Hypertension
- renal parenchymal diseases
DEFINITIONS:
- systolic and diastolic BP less than the 90th percentile for
age and sex
2. High-Normal BP
- average systolic and/or average diastolic BP's between the
90th and 95th percentiles for age and sex
3. High BP
- average systolic and/or average diastolic BP's greater than
the 95th percentile for age and sex with measurements obtained
on at least 3 occasions
4. Significant Hypertension
- BP measurements persistently between the 95th and 99th
percentiles for age and sex
5. Severe Hypertension
- BP measurements persistently at or above the 99th percentile
for age and sex
CLINICAL FEATURES:
- encircles arm circumference
2. Width
- covers 75% of the upper arm
3. Age
3. Korotkoff Sounds
- sudden distension of collapsed vessel -> onset of clear
tapping sound
- corresponds to the systolic BP
K2 - Phase II
- murmer of turbulent blood flow thru vessel narrowed by
cuff
K3 - Phase III
- murmer crisper and increased in intensity
K4 - Phase IV
- low-pitched muffled sound
- corresponds to the diastolic BP in children
K5 - Phase V
- disappearance of all sounds
- may be absent in children
- corresponds to the diastolic BP in adolescence
4. Nomograms
- male and female
- ages 0-1, 1-13, 13-18 years
2. Variables
- BP increases with age during the preadult years
- BP increases with body size
- larger children (wt and/or ht) have higher BP's than
smaller children
- BP decreases with sleep
- SBP + 7 mmHg
- DBP + 5 mmHg
- average BP vs first BP (reduces # of hypertensives)
INVESTIGATIONS:
- CBC with smear, electrolytes, BUN, creatinine, uric acid
- urine R&M, C&S
- for Neonatal Hypertension
- add calcium, plasma renin activity, renal ultrasound, and
radioisotope study
- for suspected Essential Hypertension
- add fasting cholesterol, triglycerides, high-density
lipoprotein cholesterol, LDLP cholesterol
2. Second Line
- intravenous pyelography (IVP)
- renal ultrasound
- renal radionucleotide study
- renal angiography with renal vein renins
- vascular imaging of the renal arteries
- CT - kidneys, adrenals, abdomen
- 131I-meta-iodobenzylguanidine scan
2. Hormonal Studies
- plasma renin activity
- catecholamines and metabolites - urine and plasma
- aldosterone and electrolytes - urine and serum
- free cortisol & 18-OH-cortiocosterone - urine and serum
MANAGEMENT:
- the target of management is to reduce blood pressure to a
level below the 90th percentile for age and sex in any patient
with a blood pressure greater than the 90th percentile for age
and sex using a step-wise approach:
2. Nonpharmacologic Therapy
- systolic and/or diastolic BP greater than the 90th
percentile for age and sex (High-Normal Blood Pressure)
2. Body Weight Reduction
- a positive correlation between body weight and blood
pressure exists by 2 years of age and persists to adolescence
- target - to reduce body weight to a level consistent with
the patient's sex, age, and height
- managed through regular exercise and dietary caloric and
lipid restrictions
- weight reduction will also reduce the adverse effect of
obesity on cardiovascular function by reducing serum lipid
levels and hormonal abnormalities, and by reducing peripheral
vascular resistence which will decrease the degree of left
ventricular work
3. Exercise
- physical fitness in children and adolescents is associated
with lower blood pressure
- blood pressure (both systolic and diastolic) can be
reduced significantly after 6 months of aerobic exercise
- failure to maintain aerobic conditioning results in a
return of blood pressure to pre-excercise levels
- aerobic exercise appears to be better than anaerobic or
static exercises
- exercise is contraindicated only in those children with
persistent Severe Hypertension and sports activity should be
restricted until the blood pressure is reduced below the 99th
percentile
4. Diet
- it appears that dietary sodium reduction in
sodium-sensitive people has a beneficial effect on blood
pressure
- target - to reduce dietary sodium intake to 5-6 grams of
NaCl (85-100 mEqu of sodium) per day from 7-10 grams of NaCl
per day
- avoid high salt-containing foods:
- all junk foods (TV dinners, chips, pizza, etc) and
foods from fast-food restaurants
- meats - bacon, cured ham, pork sausage,
- canned foods - soups, vegetables
- others - seasoned breadcrumbs, salad dressing, cold
cereals, spaghetti sauce, dill pickles
2. Potassium Supplementation
- although not proven in humans, potassium may have a
direct antihypertensive effect
- target - to increase the dietary potassium:sodium ratio
- foods and juices with a high potassium content tend to
be:
- fruits and vegetables - avocados, baked potatoes,
bananas, beans, cantaloupes, oranges, raisins, tomatos,
yogurt
- juices - grapefruit, milk, orange, pineapple, tomato
3. Calcium Supplementation
- controversial and premature to suggest calcium
supplementation to control hypertension until further data
is available
3. Pharmacologic Therapy
- Significant Hypertension (diastolic)
- evidence of target organ injury
- symptoms or signs related to elevated BP
2. Step-Wise Approach
- start with a small dose of a single antihypertensive drug
and increase in dosage until BP goals are reached
- if maximum dose of one antihypertensive drug is reached or
side effects become apparent without BP control then add the
next antihypertensive drug starting with a small dose and
increasing until BP goals are reached
- continue adding antihypertensive drugs in a step-wise
approach until BP goals are reached
3. Calcium Channel Blockers
- start at 5 mg po bid
- maximum dose to 20 mg po qid
- advantages:
- effective in children of all ages
- easy to administer
- rapid onset of action
- disadvantages:
- highly variable duration of action
- response tends to diminish with time
- side effects:
4. Angiotensin Converting Enzyme (ACE) Inhibitors
- start at 5 mg po bid
- maximum dose to 25 mg po qid
2. Enalapril (Vasotec)
- start at 2.5 mg po od
- maximum dose to 20 mg po od
- side effects of ACE Inhibitors
- hyperkalemia, cough, pruritis
- contraindications of ACE Inhibitors
- bilateral renal artery stenosis or renal artery
stenosis in a solitary kidney
5. Diuretics
- start at 1 mg/kg po od
- maximum dose to 10 mg/kg po od
- side effects - hypokalemia
6. Beta Blockers
- start at 0.1 mg/kg/d po bid
- maximum dose to 10 mg/kg/d po bid
2. Atenolol (Tenormin)
- start at 25 mg po od
- maximum dose to 100 mg po od
- contraindications for beta blockers: asthmatics
|