The role of routine abdominal ultrasound in newborns for detection of renal abnormalities

Abstract

Introduction Congenital and acquired renal diseases, which 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, and cortical necrosis), cystic disease (glomerulocystic kidney disease, autosomal recessive polycystic renal disease, multicystic dysplastic kidney, and cystic renal dysplasia), obstructive uropathies (ureteropelvic junction obstruction and posterior urethral valves), infections (candidal infections), and renal agenesis. The high-resolution sector and linear-array transducers allow the characterization of the underlying pathologic conditions in many cases. Findings of the renal parenchymal disease will vary on 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 on 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. The high-resolution US provides an improved characterization of the renal parenchyma and a more precise description of renal architecture. The aim of this work was to evaluate the benefit of routinely performing an abdominal ultrasound on newborns to detect possible renal abnormalities, which may be missed antenatally. Patients and methods This was a longitudinal study of 200 consecutive apparently normal neonates at Damietta University Hospital. The authors performed an abdominal ultrasound on newborns to detect possible renal abnormalities. Results In this study, the incidence of renal abnormality was found in 23 (11.5%) neonates; most abnormalities were found in males (78.3%). Moreover, the majority of abnormalities were seen in a young age group less than 20 days. In this study, regarding the ultrasound abnormality findings, three (13%) neonates had left hydronephrosis G II, with left pelviureteric junction obstruction, two (8.7%) neonates had bilateral hydronephrosis with right pelviureteric junction obstruction, two (8.7%) neonates had left multicystic dysplastic kidney and left mild nephropathy, two (8.7%) neonates had an ectopic kidney, two (8.7%) neonates had an enlarged kidney, two (8.7%) neonates had right mild multicystic dysplastic kidney and left mild hydronephrosis, and two (8.7%) neonates had right mild hydronephrosis and dilated right ureter, with right vesicoureteric reflex. There was a statistically significant difference between positive cases of ultrasound abnormality and the sex of the newborn. There was a significant statistical relation between positive cases of ultrasound abnormality and the age of the newborn. Conclusion This study has been able to demonstrate an 11.5% incidence of various types of urinary anomalies in this sample.

Keywords

• ectopic kidney
• hydronephrosis
• neonate
• pelviureteric