Kidney Swelling (Hydronephrosis)

What is Kidney Swelling (Hydronephrosis)?

Hydronephrosis is the swelling of the kidney caused by the accumulation of urine in the kidney. It is a common abnormality of the urinary tract resulting from the obstruction of the urine flow in the ureter (the tube by which urine passes from the kidney to the bladder). Hydronephrosis is mainly a congenital condition.

Causes of unilateral hydronephrosis include:

  • Partial blockage at the upper end of the ureter (the junction that connects to the kidney)

Other causes that may lead to hydronephrosis include:

  • Backflow of urine into the kidneys
  • Obstruction of the lower end of the ureter

Symptoms of untreated hydronephrosis include:

  • A large lump in the stomach
  • Pain caused by an enlarged kidney

Hydronephrosis in babies is detected through the use kidney ultrasounds and kidney function scans. The results allow the doctor to determine the location of the obstruction and suggest the best treatment option for the baby:

  • No action may be required, and in some cases, the baby’s kidney may get better over time
  • Surgery may be required if the upper end of the ureter is partially blocked

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