Acute renal failure in the newborn

Non-dialytic management of acute kidney injury in newborns

Treating acute kidney injury (AKI) in newborns is often challenging due to the functional immaturity of the neonatal kidney. Because of this physiological limitation, renal replacement therapy (RRT) in this particular patient population is difficult to execute and may lead to unwanted complications. Although fluid overload and electrolyte abnormalities, as seen in neonatal AKI, are indications for RRT initiation, there is limited evidence that RRT initiated in the first year of life improves long-term outcome. The underlying cause of AKI in a newborn patient should determine the treatment strategies to restore appropriate renal function. However, our understanding of this common clinical condition remains limited, as no standardized, evidence-based definition of neonatal AKI currently exists. Non-dialytic management of AKI in these patients may restore appropriate renal function to these patients without exposure to complications often encountered with RRT.

US of renal insufficiency in neonates

Congenital and acquired renal diseases that can produce renal insufficiency during the neonatal period may be classified according to their ultrasonographic (US) characteristics: increased parenchymal echogenicity (renal parenchymal diseases, angiotensin-converting enzyme inhibitor fetopathy, cortical necrosis), cystic disease (glomerulocystic kidney disease, autosomal recessive polycystic renal disease, multicystic dysplastic kidney, cystic renal dysplasia), obstructive uropathies (ureteropelvic junction obstruction, posterior urethral valves), infections (candidal infections and bezoars), and renal agenesis. High-resolution sector and linear-array transducers allow characterization of the underlying pathologic conditions in many cases. Findings of renal parenchymal disease will vary at Doppler US and, during the acute phase, diastolic flow can be decreased, absent, or reversed. In patients with glomerulocystic kidney disease, US shows bilaterally enlarged kidneys with diffusely increased echogenicity and retention of a reniform contour, loss of corticomedullary differentiation, and cortical cysts. Obstruction of the ureteropelvic junction, the most common cause of hydronephrosis in neonates, can be seen at US as a dilated renal pelvis with dilated and communicating calices, lack of dilatation in the distal portion of the ureter, changes of renal dysplasia with increased echogenicity of the renal parenchyma, and parenchymal cysts, depending on the severity and duration of the obstruction. High-resolution US provides improved characterization of the renal parenchyma and more precise description of renal architecture.