Transient Hyperechogenic Medullary Pyramids in a Neonate With Acute Kidney Injury

A neonate with acute kidney injury can present with decreased urine output and signs of dehydration. Sonography is used to evaluate the kidneys for structural deformities. A normal sonographic image of a neonatal kidney would show hypoechoic pyramids of the medulla. However, less frequently occurring neonatal transient renal failure with renal medullary hyperechogenicity has been linked to severe perinatal renal damage, kidney abnormalities, or nephrocalcinosis. A simple conventional sonography in neonates can be helpful in predicting the severity of renal damage in such cases. Hyperechogenecity of the medulla in contrast to the normal hypoechogenic medulla of normal neonates can be due to multiple causes. However one must bear in mind that this finding of hyperechoic tips of renal pyramids is not indicative of intrinsic renal disease and subsides without intervention if physiologic or with rehydration if due to hypernatraemic dehydration. It is important for a physician to know about this physiological variant seen in neonates who present with dehydration.