From the Guidelines
A pelvic kidney in a newborn is a congenital condition that typically requires monitoring but not immediate intervention, with a management approach involving renal ultrasound and potentially a voiding cystourethrogram (VCUG) to check for vesicoureteral reflux, as recommended by the American College of Radiology 1. The condition is characterized by one or both kidneys remaining in the pelvis instead of ascending to their normal position during fetal development.
Key Considerations
- The kidneys form in the pelvis and typically ascend to the upper abdomen by the ninth week of gestation; when this ascent fails, the kidney remains in the pelvis, which is a developmental variation rather than a disease.
- Regular follow-up with a pediatric nephrologist or urologist is essential, with monitoring of blood pressure, growth, and renal function tests.
- Most pelvic kidneys function normally and don't require surgical correction.
- Parents should be educated about potential complications such as urinary tract infections, which may present with fever, irritability, poor feeding, or foul-smelling urine in newborns.
Diagnostic Approach
- Renal ultrasound is usually appropriate for the initial imaging of neonates with an antenatal diagnosis of hydronephrosis, as stated in the ACR Appropriateness Criteria 1.
- A follow-up ultrasound in 1 to 6 months may be recommended for neonates with a normal ultrasound and an antenatal diagnosis of hydronephrosis.
- For male children with moderate or severe hydronephrosis on initial neonatal ultrasound, a fluoroscopy VCUG or MAG3 renal scan may be appropriate to evaluate for vesicoureteral reflux and other urologic abnormalities 1.
Management
- Prophylactic antibiotics are not routinely recommended unless there is vesicoureteral reflux or recurrent infections.
- The management approach should be individualized based on the severity of the condition and the presence of associated urologic abnormalities.
- The goal of management is to prevent long-term complications such as urinary tract infections, renal scarring, and chronic kidney disease, while also monitoring for potential complications and providing supportive care as needed 1.
From the Research
Implications of a Pelvic Kidney in a Newborn
- A pelvic kidney can be associated with obstetrical obstruction, as reported in a case study where a child was delivered by caesarean section due to obstruction of the birth canal 2.
- Prenatal diagnosis of a pelvic kidney is possible through ultrasonography, and its significance is discussed in a case report 3.
- Newborns with extra-renal pelvis, a common ultrasonographic finding, are at a higher risk of urinary tract infections (UTIs) and minor congenital malformations 4.
- The incidence of UTIs in neonates with extra-renal pelvis is higher than in those with normal ultrasound scans, and is not solely attributed to vesicoureteral reflux 4.
- Newborns with UTIs may exhibit non-specific symptoms such as low-grade fever or jaundice, and urinalysis may be negative in some cases 5.
- Congenital anomalies of the kidney and urinary tract are common in newborns with UTIs, emphasizing the need for renal imaging 5.