Measurement and treatment of elevated blood pressure in the pediatric patient with chronic kidney disease.

Hypertension, as in adults, is a frequent complication found in children with chronic kidney disease (CKD). Indeed, hypertension has now become one of the most prevalent chronic diseases of childhood. The most recent data available (2003) indicate that at least 38% of children with CKD in the United States are receiving antihypertensive therapy. Only recently has it been shown in children that hypertension, traditionally considered a marker for disease severity in children, is additionally a significant and independent risk factor for accelerated deterioration of kidney function and progression of CKD and a significant risk factor for cardiovascular disease. The following review outlines the differences and similarities of childhood versus adult hypertension with respect to measurement, diagnosis, treatment, and consequence in CKD. The definition of hypertension changes continually as a child grows with or without CKD. Despite numerous guidelines, the diagnosis of childhood hypertension continues to be based on epidemiologic data rather than evidence. For children, the current definition includes 2 categories: high normal, which is blood pressure (BP) between the 90th and 95th percentile, and hypertensive, which is BP above the 95th percentile. The evaluation of all hypertensive children should include a complete assessment of end-organ damage, including eyes, cardiovascular system (including blood vessels), kidneys, and nervous system. For children with CKD and end-stage renal disease (ESRD), a high percentage have left ventricular hypertrophy (LVH). The finding of end-organ damage or comorbidity (CKD, diabetes) in any child is an absolute indication for immediate pharmacologic therapy, whereas the presence of hypertension above the 95th percentile in children without CKD warrants initial intervention such as life style modification. The guidelines for measurement of BP in children with CKD are similar to those in children without CKD and include casual BP measurement, self-measured BP, and ambulatory BP monitoring. The recommendation for BP measurement in children is, when permitted, by auscultative method with a well-calibrated mercury manometer. Most casual BP measurements are performed with an automated oscillometric device whose validation has not been confirmed in children with CKD. The ambulatory BP monitor (ABPM) has 2 advantages: it significantly correlates with the presence of end-organ damage, and it identifies abnormal BP patterns that are frequently present in CKD patients, such as hypertension during the sleep period. An abnormal ABPM pattern can also be predictive of the development of end-organ damage. Treatment of hypertension in children, with and without CKD, is based on 3 factors: degree of BP elevation, the presence of cardiovascular risk factors, and the presence of end-organ damage. Additionally, the initial antihypertensive agent may be selected on available and age-appropriate formulations (eg, suspension and dosage selection). A physician treating a hypertensive child with CKD faces multiple challenges. They include selecting the convenience of available automated devices and the ABPM versus traditional auscultatory techniques upon which all normative standards have been based. Current research initiatives propose to develop pharmacokinetic and pharmacodynamics properties of antihypertensive medications and to study the effect of early intervention on end-organ damage.