NEPHROCALCINOSIS IN VERY-LOW-BIRTH-WEIGHT NEONATES - SONOGRAPHIC PATTERNS, HISTOLOGIC CHARACTERISTICS, AND CLINICAL RISK-FACTORS

Fifty infants weighing less than 1200 grams at birth who survived at l east 3 weeks were enrolled in this study, of whom 14 (28%) developed s onographic evidence of nephrocalcinosis by 9 weeks, despite median tot al furosemide dose of only 2 mg/kg. Risk factors for development of ne onatal nephrocalcinosis were white race (P < 0.01) and positive family history of kidney stones (P < 0.001). Sonography demonstrated echogen ic foci measuring 2 to 9 mm near the papillary tips in most infants wi th nephrocalcinosis even though the kidneys apparently had not progres sed through the stages of diffuse medullary echogenicity that Patriqui n and Robitaille postulated are the sonographic correlates of the Ande rson-Carr-Randall progression, a leading theory of renal calculus form ation. The presence of intratubular calcifications in the two patients studied post mortem also is contrary to the Anderson-Carr-Randall the ories that center on interstitial calcium deposition. Although neonata l nephrocalcinosis shares some clinical risk factors (white race and p ositive family history of renal calculi) with renal calcium deposition in older children and adults, the prevalent theories of renal calcium deposition do not account for its sonographic or histologic manifesta tions. -