Dr. A.K. Singal MBBS (Gold Medalist), DNB, MNAMS
M.CH (AIIMS, Gold Medalist)
Stecker Scholar Pediatric Urology (USA)

Knowledge Bank

  • UPJ obstruction: blockage at the left ureteropelvic junction (where ureter joins to the kidney)
  • Posterior urethral valves: blockage at the outlet of the bladder
  • Vesicoureteral reflux on the left: flow of urine back up ureter causing dilated ureter and kidney
  • Multicystic kidney on the left: kidney may be large, leading to detection on ultrasound
  • Duplication of ureters on both sides with ureterocele (seen where ureter joins bladder) on left causing bolckage

Antenatal Hydronephrosis

  • What Antenatal Diagnosis means?

    Antenatal diagnosis or diagnosis of disorders while the baby is still in mother’s womb is the cutting edge of medical science. The once opaque womb has been rendered transparent due to free availability of high resolution ultrasound. Two decades back pediatricians and pediatric surgeons used to get frustrated when they used to see a baby with a severe congenital malformation. They used to feel that “I wish I was there earlier”.

    Ultrasound typically can pick up structural abnormalities in the developing babies especially after 16 weeks once the miniature organs are in place. As expected the specificity is more as the baby grows bigger. This has generated a whole new group of diseases- “Antenatally diagnosed disorders” or we call them “Unborn Patients”

    Kidney abnormalities are one of the most common antenatal disorders, found in approximately 1% of all fetuses but the good part is that in up to 80% of them it may represent transient changes in form of slight swelling which goes away by itself either before or after birth. These anomalies are diagnosed before the baby is born and referred for an opinion of an expert pediatric urologist even before birth.

    The major groups of anomalies seen in unborn babies are kidney abnormalities (swelling, absent kidney), hydrocephalus (excessive brain fluid leading to pressure damage on brain), cardiac anomalies, neural tube defects, certain chromosomal disorders, lung anomalies, tumors and cysts in belly.

  • Definition of Antenatal Hydronephrosis?

    Antenatal hydronephrosis refers to fluid-filled enlargement of the kidney detected before birth in the fetus by ultrasound studies. Hydronephrosis can be detected as early as the 15 weeks of pregnancy. In most instances this diagnosis will not change obstetric care but will require careful follow-up and possible evaluation & surgery during infancy and childhood by an expert pediatric urologist.

  • What causes antenatal hydronephrosis?

    Possible causes of antenatal hydronephrosis include:

    • Blockage: this may occur at the kidney in the Ureteropelvic junction (UPJ/ PUJ) called PUJ obstruction, at the bladder in the ureterovesical junction, or in the urethra (posterior urethral valves).
    • Reflux: Vesicoureteral reflux occurs when the valve between the bladder and the ureter does not function properly, permitting urine to flow back up to the kidney when the bladder fills or empties. Most children (75%) outgrow this during childhood but need daily antibiotic prophylaxis to try to prevent kidney damage before they outgrow the reflux.
    • Duplications: perhaps 1% of all humans have two collecting tubes from a kidney. These may show up on fetal ultrasound. Occasionally patients with duplication have a ureterocele, which is a balloon-like obstruction at the end of one of the duplex tubes.
    • Multicystic kidney: This is a nonfunctional cystic kidney.
    • Transient Hydronephrosis - Many of these dilated kidneys become normal after delivery.

    It is best to consult a pediatric urologist surgeon once the baby is diagnosed to have fetal hydronephrosis for good treatment after birth and plan it well in advance.

  • How is antenatal hydronephrosis managed?
    Most cases of hydronephrosis diagnosed during pregnancy are just followed with ultrasound, monitoring the growth of the fetus. liquor and the condition of the kidneys. In these cases, a routine, normal delivery can be performed. Rarely, in a fetus with severe obstruction of both kidneys and insufficient amniotic fluid, drainage of the kidneys or bladder by tube or operation may need to be done. Some of these babies especially with posterior urethral valve with falling urine output as seen by Oligohydramnios which is decreasing liquor, need to be delivered early. In these babies, however, the kidneys are often very abnormal and do not function properly regardless of treatment. These decisions and treatment is best provided by a multidisciplinary team led by a pediatric urologist.
  • What is done to evaluate the hydronephrosis after the baby is born?

    Several studies may need to be performed to evaluate the kidneys:

    • Ultrasound to check size, swelling of the kidneys, ureter and bladder, it is done during the newborn period.
    • Voiding cystourethrogram is done in cases where PUV or vesicoureteral reflux is suspected.
    • Diuretic renal scan to evaluate kidney function and drainage especially used for PUJ obstruction
    • DMSA scan for checking cortical function of the kidney in selected cases of VUR
    • CT-IVP- in case some anatomical issue is there to delineate clear anatomy but is rarely required these days due to good USG and renal scans.
  • What can be done to treat the hydronephrosis?
    The treatment of antenatal hydronephrosis depends on the underlying cause. Infants and children with who have vesicoureteral reflux are managed with antibiotics and surveillance with periodic ultrasounds and voiding cystograms. Infants and children with an obstruction or blockage of the urinary tract may require surgical correction. Babies with hydronephrosis without reflux or obstruction are followed with periodic ultrasounds to monitor the hydronephrosis and the growth of the kidneys. The management of multicystic dysplastic kidneys is controversial: the multicystic dysplastic kidney doesn't work, but the opposite kidney is usually normal. Some urologists recommend removal, whereas others do not remove the dysplastic kidney unless its large size causes problems or unless there is a question of tumor or blockage
  • Pediatric Urology Clinic at MITR Hospital, Kharghar, Navi Mumbai
    Dr A.K.Singal is a renowned Pediatric Urologist living and working in Navi Mumbai. He is an expert in diagnosing and treating cases of antenatal hydronephrosis. Children from all over Mumbai, Navi Mumbai, Thane and Pune come to his clinic for diagnosis and treatment of urological issues. Dr Singal does antenatal counselling in pregnancy for planning treatment of antenatal hydronephrosis as well.

See cases of antental hydronephrosis here:

Case 4: Child with posterior urethral valve

Case 8: Child with antenatal hydronephrosis and PUJ Obstruction

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