Hydronephrosis in Children

Hydronephrosis is the term used when urine builds up in the kidneys and cannot drain out to the bladder. It is caused by a blocked or narrow ureter (the tube that leads from the kidney to the bladder).

When the urine backs up, the kidney swells. Eventually, this can lead to decreased kidney function.

In adults, hydronephrosis can be caused by a number of conditions, from kidney stones to bladder cancer to scar tissue in the urinary tract.

About one percent of children are born with hydronephrosis. The most common cause is obstruction of the ureteropelvic junction – where the ureter meets the bladder. The baby's ureter may be too narrow at that spot, or blood vessels may be crossed over the ureter, causing a kink that slows or blocks the flow of urine.

Finding Hydronephrosis in Children
Treating Hydronephrosis

Often, hydronephrosis clears up after birth, during a baby's first two years. If, instead, it worsens over time, surgery may eventually be necessary. At Swedish, a minimally invasive procedure called robotic pyeloplasty is done as appropriate for children and adolescents with hydronephrosis.

Finding Hydronephrosis in Children

An unborn baby's swollen kidney is visible on an ultrasound screening. Additional testing will be done after birth to determine how severe the condition is.

In older children with mild cases, there may not be any symptoms. If hydronephrosis becomes severe, symptoms may include:

  • Pain in the back, waist, lower abdomen, or groin
  • Recurrent urinary or kidney infections
  • Persistent pain with urination
  • Blood in the urine

Tests to determine the underlying cause of hydronephrosis may include:

  • Voiding cystourethrogram: taking X-rays of the bladder and urethra during urination
  • Ultrasound: using sound waves to examine the kidneys, ureter and bladder
  • MRI or CT scans: using magnetic waves to make pictures of the kidneys, bladder and ureter
  • Cystoscopy: inserting a thin, lighted tube through the urethra and into the bladder to examine the lining

Treatment for Hydronephrosis

Hydronephrosis can be mild, moderate or severe. It can occur in one or both kidneys. Babies born with hydronephrosis are monitored to see what treatment might be necessary.

In severe cases, pyeloplasty surgery may be needed. Methods of pyeloplasty include:

  • Open surgery: involving an incision made on the child's abdomen
  • Laparoscopic pyeloplasty: surgery done using rigid instruments inserted through a number of small incisions while viewing a flat screen
  • Robotic pyeloplasty: an advanced method of laparoscopy that uses flexible instruments and gives the surgeon a magnified view in three dimensions

At Swedish, pyeloplasty is usually done as an open procedure on infants. Their kidneys can be accessed through a very small incision. And unlike adults, they recover quickly from open incisions.

But for children and adolescents, or patients who are obese, the more flexible tools and enhanced viewing made available through robotic surgery make it a good surgical option.