PRENATALLY DIAGNOSED BILATERAL HYPERECHOIC KIDNEYS WITH NORMAL AMNIOTIC-FLUID - POSTNATAL OUTCOME

We evaluated a subset of infants with bilateral markedly hyperechoic ' 'bright'' kidneys noted prenatally in association with normal amniotic fluid volume during gestation. Prenatal ultrasound showed increased r enal parenchymal echogenicity bilaterally with preservation of the med ullary pyramid architecture. These children were followed for up to 3 years to determine potential changes in the sonographic appearance of the echogenic renal parenchyma and to assess renal function. In 3 year s 8 cases of bilateral hyperechoic fetal kidneys were identified. Duri ng postnatal followup renal echogenicity resolved in 4 cases, diminish ed in 1 and remained the same in 3. The serum creatinine and electroly tes were normal in all cases followed for more than 3 months. Other re nal findings included vesicoureteral reflux in 2 of 7 cases, mild pelv ic ectasia in 1 and tiny medullary calcifications in 1. The specific e tiology of increased echogenicity is unknown, although 1 infant appear ed to have a form of autosomal recessive disease with liver hyperechog enicity as well. We conclude that fetuses with bilateral hyperechoic k idneys associated with normal amniotic fluid volume have a favorable o utcome. Ultrasonographic finding of marked parenchymal hyperechogenici ty appears to improve with time; in our experience renal function is n ormal and the infants thrive. Continued followup is necessary to deter mine the long-term natural history of this phenomenon, as is subsequen t prenatal and postnatal evaluation of future siblings to assess genet ic risk.