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Mild to moderate postnatal hydronephrosis—grading systems and management

Abstract

No universal guidelines exist for the management of patients with mild to moderate antenatal hydronephrosis (ANH). Unsurprisingly, practice patterns vary considerably with respect to recommendations for postnatal evaluation and follow-up imaging schedule. Although some clinical tools are available to specifically grade ANH and postnatal hydronephrosis, these are commonly used interchangeably with varying degrees of success. A universal classification system and nomenclature are needed to best identify patients at risk of renal deterioration, UTI and need for surgical intervention. We present our own approach to postnatal risk stratification and management, including recommendations regarding serial ultrasonography schedule, prophylactic antibiotics, voiding cystourethrogram and renal scintigraphy.

Key Points

  • No universal guidelines for the clinical management of patients with mild to moderate antenatal hydronephrosis (ANH) are currently available

  • Anteroposterior diameter (APD) measurements of the fetal renal pelvis and Society for Fetal Urology (SFU) grade are the two most-commonly used grading systems for ANH

  • Patients with SFU grade 1 or 2 hydronephrosis or postnatal APDs <20 mm (measured on ultrasonography) are likely to be at low risk for significant pathology, renal deterioration and a subsequent need for surgery

  • By contrast, prophylactic antibiotics and complete evaluation is warranted for patients with SFU grade 4 hydronephrosis or APDs >30 mm

  • The likelihood of progression to renal deterioration and need for surgery in patients with SFU grade 3 or bilateral grade 2 hydronephrosis (or APDs 20–30 mm) is unclear

  • Accordingly, these intermediate-risk patients should probably receive antibiotic prophylaxis and voiding cystourethrogram and be closely monitored

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Figure 1
Figure 2: The Society for Fetal Urology grading system for postnatal hydronephrosis.
Figure 3: Proposed risk-stratification scheme for postnatal hydronephrosis.

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Both authors researched the data for the article, discussed its content, wrote the manuscript and edited it before submission.

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Correspondence to Matthew D. Timberlake.

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Timberlake, M., Herndon, C. Mild to moderate postnatal hydronephrosis—grading systems and management. Nat Rev Urol 10, 649–656 (2013). https://doi.org/10.1038/nrurol.2013.172

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