A newborn with Antenatal Hydronephrosis and Pelvi-ureteric junction obstruction
Master M.T. was diagnosed to have Antenatally diagnosed hydronephrosis (kidney swelling diagnosed before birth by ultrasound (USG) of the pregnant mother) in 7th month of intrauterine life (30 weeks) on a routine Antenatal USG. The hydronephrosis was unilateral (AP diameter of pelvis 16mm) and the right kidney was normal. There were no other abnormalities detected. Parents were counseled and pregnancy was followed up and a repeat USG was advised at 36 weeks. The swelling on the left side had increased (AP diameter of pelvis- 22mm).
Baby was delivered at term by normal vaginal delivery and passed urine in day 1. On clinical examination there was no lump palpable. A repeat USG at one week of age showed persistent hydronephrosis on left side with AP diameter of 20mm. A Nuclear Renal scan to determine renal function and also drainage was done at 4 weeks of age showed Left PUJ obstruction with non-draining curve and significant retention of tracer even at 2 hours (see picture). Fortunately, the renal function was preserved (LK-46%, RK-54%). Baby was kept on close follow-up as there were chances that he may require surgery. A USG was again repeated at 2 months of age and it showed worsening hydronephrosis with AP diameter of 30mm. There was some cortical thinning also with calyceal dilatation. A detailed discussion was held with parents and a decision for pyeloplasty (Surgery to correct the obstruction) was made.
Before surgery a cystoscopy and retrograde pyelogram was done to delineate the anatomy more clearly- it confirmed pelvi-ureteric junction obstruction (see picture). Pyeloplasty was completed uneventfully and baby was discharged after 3 days. A small indwelling tube called DJ stent was left inside the kidney to allow for good healing and faster discharge. DJ stent was removed after 6 weeks by cystoscopy. A follow-up USG at 3 months showed reduction of hydronephrosis and a nuclear scan at 6 months showed normalization of drainage curves and minimal retention in delayed images (see picture 3).
DTPA scan showing Left PUJO, there is significant retention of tracer even at 2 hours. Curve is non-draining type
DTPA scan 6 months after surgery showing good drainage and normal drainage curve.
Rterograde pyelogram showing features of Pelviureteric Junction Obstruction
Facts about Antenatal Hydronephrosis
  • Antenatal Hydronephrosis is by far the most common antenatal abnormality detected in the baby before birth on USG (Ultrasound) done during pregnancy- upto 1% of all pregnant mothers may have fetuses with some degree of Hydronephrosis- 1 out of every100 mothers will have a baby with some (mostly minor) degree of Hydronephrosis in the developing baby.
  • PUJO is the most common cause of Antenatally diagnosed hydronephrosis.
  • 70% of these hydronephrosis may resolve spontaneously before birth or within first few months of life.
  • For a one sided hydronephrosis and if the other kidney is normal- a USG should be done after 5-7 days of birth. The USG may not show valid information first few days of life due to rapid fluid shifts which occur in the small baby immediately after birth.
  • It is important to follow-up all these children to identify those in which hydronephrosis persists and these may require further observation & evaluation.
  • Kids with persistent hydronephrosis may have ongoing silent kidney damage and should be evaluated thoroughly.
  • Even when PUJO is diagnosed, if the hydronephrosis is stable and renal function preserved surgery may not be required in all cases. But a close follow-up is a must till hydronephrosis resolves.
  • During surgery a small stent called DJ stent (double J stent) is often left across the anastomosis to help in better healing of the surgical repair site and allow for early discharge. This is removed after 4-6 weeks.
  • Other causes of antenatal hydronephrosis like vesicoureteric reflux (VUR) and posterior urethral valves have to be differentiated and they require a separate management plan.
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