ANTENATALLY DETECTED HYDRONEPHROSIS (ANH): What to Remember?(WTR?)

When to Worry?

• APD ≥4 mm in 2nd trimester and ≥7 mm in 3rd trimester.
• ANH with oligohydramnios
• ANH with extra-renal anomalies and soft markers
• ANH with any calyceal dilatation, renal parenchymal changes, bladder wall abnormalities.

When to do a post-natal scan?

• USG KUB after adequate hydration, 3-7 days.
• MCU after 4-6 weeks
• USG KUB and MCU within 48 hours, if lower urinary tract obstruction.

When to treat?

• Severe hydronephrosis- APD > 10mm - peripheral calyceal dilatation, renal parenchymal changes, bladder wall abnormalities, ureter abnormalities.
• PUV or lower urinary tract obstruction - Surgical approach
• VUR - Antibiotic Prophylaxis
• Normal MCU - Diuretic venography (after 4-6 weeks) to differentiate obstructive and non-obstructive hydronephrosis and for assessment of renal function.