Nephrocalcinosis in childhood

Abstract

Nephrocalcinosis (NC) describes the deposition of calcium-oxalate or calcium-phosphate crystals in the tubuli or interstitial kidney parenchyma. Whereas kidney stones are formed in every age NC is most frequently seen during the first years of life. Because of multiple causative factors NC is a diagnostic challenge. A mostly metabolic reason for the development of nephrocalcinosis can be identified in up to 75% of patients and hence adequately be treated. An imbalance of lithogenic and inhibitory substances is the pathophysiologic basis for the development of nephrocalcinosis. This imbalance is either transient, for example in patients with alimentary hyperoxaluria or short term immobilization induced hypercalciuria, or ongoing, e.g., in tubulopathies or inborn errors of metabolism. Hypercalciuria is the most prominent promotor for the development of nephro- calcinosis, either accompanied by hypercalcemia or not. Both hyperoxaluria, in its primary or secondary forms, as well as hypocitraturia, e.g., in renal tubular acidosis, or in the premature infant, are further specific risk factors. Of course, although mostly clinically silent, early diagnosis is mandatory to start treatment, which may help not only to prevent progression of NC but end stage renal failure relying on the underlying diseases.