Nomograms relating aldosterone excretion to urinary sodium and potassium in the pediatric population: their application to the study of childhood hypertension.

Abstract

The lability and diurnal variation of blood pressure in normal and hypertensive children were examined and found to be less than that described in adults. Nomograms were prepared relating urinary sodium and potassium to urinary aldosterone in children ranging in age from infancy to 22 years. These nomograms reveal that the relation of aldosterone excretion to sodium excretion is described by a hyperbolic function. Most values for normal children, children with mild essential hypertension and children with severe essential hypertension fell between two hyperbolic curves representing the 5th and 95th percentile, respectively. Hypertensive children with low and high plasma renin activity were found to have an inappropriately high level of urinary aldosterone excretion in relation to urinary sodium excretion. No relation was found between potassium and aldosterone excretion. By means of these nomograms the normal standards for aldosterone excretion in children were refined, permitting classification of hypertensive children into distinct groups. This classification may have prognostic significance.