Chapter 39 Hypertension
PATHOPHYSIOLOGY
Hypertension in the pediatric client is described as blood pressure that is persistently between the 90th and 95th percentiles. Table 39-1 identifies guidelines (based on age and sex) for suspect blood pressure values. A variety of mechanisms are associated with hypertension. The renin-angiotensin-aldosterone system maintains fluid volume and vascular tone through the production of angiotensin II (a vasoconstrictor) and the stimulation of aldosterone production (for sodium retention). The sympathetic nervous system affects peripheral vascular resistance, cardiac output, and renin release, influencing the regulation of blood pressure.
Table 39-1 Approximate Guidelines for Suspect Blood Pressure
| Age (years) | Blood Pressure (mm Hg) | |
|---|---|---|
| Supine Position—Lowest of Three Readings | ||
| Boys and girls | 3–5 | 110/70 |
| 6–9 | >120/75 | |
| 10–14 | >130/80 | |
| Seated Position—Average of Second and Third Readings | ||
| Girls | 14–18 | >125/80 |
| Boys | 14 | >130/75 |
| 15 | >130/80 | |
| 16–18 | >135/85 | |
Modified from Gilles S, Kagan B: Current pediatric therapy, ed 13, Philadelphia, 1990, WB Saunders.
Hypertension is classified as primary or secondary. Primary hypertension can be ascribed to no identifiable cause, whereas secondary hypertension is attributable to a structural abnormality or to an underlying disease (renal, cardiovascular, endocrine, central nervous system, or collagenous). A variety of factors have been identified as contributing to hypertension, including diet (high in calories, saturated fats, and sodium), contraceptive use, positive family history, obesity, and minimal physical exercise. Children generally manifest no overt symptoms. If symptomatic, the disease may be quite severe. Prognosis is variable, depending on the age of onset and response to treatment.
Problems evident in adults may have originated during the first or second decade of life. The earlier the onset, the more severe the disease will be.
INCIDENCE
1. Incidence is increased among children in lower socioeconomic groups.
2. Incidence is increased among African-American adolescents.
3. Incidence rates vary from 0.6% to 20.5% (depends on methodology used).
4. Noncompliance with treatment occurs among more than 50% of affected children; compliance improves when the child is dependent on the parent.
5. Males are affected more often than females.
6. In individuals 2 to 18 years of age, 45% to 100% of cases of hypertension are attributed to primary hypertension.
7. Of children with primary hypertension, 25% have a positive family history of the disorder.
8. Overall, 1% to 2% of children and 11% to 12% of adolescents are affected.
9. Hypertension is most often associated with coarctation of the aorta or renal disease.
CLINICAL MANIFESTATIONS
LABORATORY AND DIAGNOSTIC TESTS
1. Urinalysis, urine culture—to assess for renal cause
2. Serum electrolyte levels—to assess for renal and metabolic status
3. Complete blood count—to assess for infection, fluid overload
4. Creatinine, blood urea nitrogen levels—to assess for renal cause
5. Serum cholesterol level—higher than 250 mg/100 ml
6. Serum triglyceride level—increased
7. Lipoprotein electrophoresis—elevated lipoprotein levels
8. Electrocardiogram—left ventricular hypertrophy
9. Chest radiographic study—left ventricular hypertrophy
10. Rapid-sequence intravenous pyelogram—to assess activation of renin-angiotensin system
11. Plasma renin activity study—to assess activation of renin-angiotensin system
12. Excretory venogram—to detect renal and renovascular abnormalities
13. Arteriogram—to detect renal and renovascular abnormalities
14. Radionuclide studies—to detect renal and renovascular abnormalities
MEDICAL MANAGEMENT
The aim of controlling hypertension is to reduce the associated risk of cardiovascular and renal complications. The step approach to treatment for the pediatric client is to educate the child and family on the importance of prevention. Nonpharmacologic interventions such as diet adjustment, exercise, and weight control should be the first approach when possible. The goal of antihypertensive therapy is to maintain pressure below the 90th percentile using the least amount and number of drugs. Medications should be started one at a time using a diuretic, beta-blocker, or calcium antagonist. Keeping the medication schedule as simple as possible helps to promote compliance.
NURSING INTERVENTIONS
Flynn JJ. Pharmacologic management of childhood hypertension: current status, future challenges. Am J Hypertens. 2002;15(2 pt 2):30S.
Friedman AL. Approach to the treatment of hypertension in children. Heart Dis. 2002;4(1):47.
Robinson RF, et al. Secondary pediatric hypertension. Pediatr Nephrol. 2004;19(12):1379.
Schell KA. Evidence-based practice: Noninvasive blood pressure measurement in children. Pediatr Nurs. 2006;32(2):263.
Sorof J, Daniels S. Obesity hypertension in children: a problem of epidemic proportions. Hypertension. 2002;40(4):441.
