Differential diagnosis of abdominal masses in the neonate

Evaluation of renal function and acute renal failure in the neonate

The diagnosis of renal dysfunction in the neonate can be a challenging problem for the practicing pediatrician. Although there are real differences in renal function between term and preterm infants, overall function is quite adequate in both groups when fluid intake and environmental conditions are carefully controlled. When confronted with an infant with a pathologic decrease in urine output, the clinician must provide adequate fluid resuscitation for the infant with prerenal oliguria without inducing fluid overload in the infant with established, intrinsic renal failure. In addition, the infant with obstruction to urine flow must be distinguished. This requires careful assessment of physical findings and a few key laboratory determinations. Once the diagnosis of renal failure is made, frequent clinical monitoring with anticipation of potential complications is critical. Long-term management of renal failure in infancy and intervention for suspected urinary tract malformation in the fetus have emerged as difficult medical and ethical problems as our technology has advanced.

Nephrosonography and renal scintigraphy in evaluation of newborn with renomegaly

Prompt diagnosis of renomegaly in the newborn is necessary for appropriate medical or surgical management to insure maximal recovery of renal function. To investigate both renal structure and function without iodinated contrast infusion, combined ultrasonography and nuclear scintigraphy were evaluated in 17 newborns with renomegaly and 6 infants with cystic renal abnormalities detected in utero. In 18 patients, intravenous pyelography (IVP) and/or voiding cystourethrography (VCUG) were performed subsequently. While ultrasonography or scintigraphy alone provided the major diagnosis in 48 per cent and 30 per cent of cases, respectively, the combination of both studies yielded the major diagnosis in 87 per cent. Subsequent IVP was less informative than combined sonography and scintigraphy in 5 of 15 patients, and VCUG confirmed the final diagnosis in 4 of 13 patients. We conclude that initial evaluation of the newborn with renomegaly should comprise ultrasonography followed by nuclear scintigraphy. This combination of studies provides adequate information to determine subsequent management in nearly 90 per cent of cases without subjecting infants to the risks of contrast infusion or higher doses of diagnostic levels of radiation.