[Nephrocalcinosis in childhood. Sonographic findings and differential diagnosis].

Ultrasonography is the method of choice for the detection of medullary or cortical nephrocalcinosis in infancy and childhood. Compared with abdominal radiographs and computed tomography even smallest calcifications are detected more accurately. Using furosemide, ACTH, steroids or high doses of vitamin D, early forms of medullary nephrocalcinosis associated with a faint hyperechogenic rim at the margins of the renal pyramids can be diagnosed by ultrasound. Idiopathic hypercalciuria, Bartter's syndrome and renal tubular acidosis cause medullary nephrocalcinosis, whereas cortical nephrocalcinosis is the result of renal vein thrombosis; primary hyperoxaluria is associated with cortico-medullary calcifications. Due to the localisation of the nephrocalcinosis and the age distribution of the diseases, sonography merely enables us to narrow down differential diagnosis.