Antenatally detected urinary tract dilatation: long-term outcome

Area of Science:

• Pediatric Nephrology
• Fetal Medicine
• Urology

Background:

• Antenatally diagnosed urinary tract dilatation (UTD), formerly antenatal hydronephrosis, presents diagnostic challenges due to varied definitions.
• Approximately one-third of UTD cases resolve prenatally, one-third postnatally within early childhood, and the remainder persist or indicate congenital anomalies of the kidney and urinary tract (CAKUT).

Purpose of the Study:

• To review updated knowledge on the long-term outcomes of children diagnosed with antenatal UTD.
• To clarify the prognosis and management of UTD based on severity and postnatal findings.

Main Methods:

• Literature review of studies on antenatal UTD and its long-term sequelae.
• Analysis of definitions, resolution rates, risk factors for CAKUT and urinary tract infections (UTIs), and long-term renal function.

Main Results:

• UTD resolution occurs in about two-thirds of cases before or shortly after birth.
• The risk of postnatal CAKUT diagnosis correlates with dilatation severity, but not with vesicoureteral reflux (VUR).
• UTIs affect 7-14% of children with UTD; risk is higher with VUR and hydroureteronephrosis.
• Permanent kidney damage occurs in ~40% of moderate/severe UTD cases, while hypertension and reduced eGFR are rare (0-5%). Mild UTD shows excellent long-term outcomes.

Conclusions:

• Mild antenatal UTD requires minimal follow-up due to excellent long-term prognosis.
• Moderate to severe UTD warrants careful monitoring for potential kidney damage, though severe complications are infrequent.
• Standardized definitions and risk stratification are crucial for managing antenatal UTD and optimizing patient outcomes.