Bilateral hydronephrosis

Alternative names

Hydronephrosis - bilateral

Definition

Bilateral hydronephrosis is the distention of the pelvis and calyces of both kidneys. (See also unilateral hydronephrosis.)

Causes, incidence, and risk factors

Bilateral hydronephrosis develops when the pelvis and calyces (the urine collecting structures of the kidneys) of both kidneys become distended because urine is unable to drain from the kidney down the ureters into the bladder. (Bilateral means both sides.)

Hydronephrosis is therefore not itself a separate disease, but rather a physical manifestation of the disease process that keeps urine from draining out of the kidneys, ureters, and bladder. The symptoms, treatment, and expected outcome are those of the associated diseases.

Disorders associated with hydronephrosis include:

• acute bilateral obstructive uropathy
  
• chronic bilateral obstructive uropathy
  
• vesicoureteric reflux
  
• uteropelvic junction obstruction
  
• posterior ureteral valves
  
• neurogenic bladder
  
• bladder outlet obstruction
  
• prune belly syndrome
  

Advances in fetal ultrasound have given specialists the ability to diagnose obstructive uropathy (problems caused by the blockage of the urinary system) in the fetus before birth. Unilateral (one side only) or bilateral (both sides) obstruction of the urinary tract can be diagnosed by fetal ultrasound. Fetal conditions such as uteropelvic junction obstruction, posterior ureteral valves, and prune belly syndrome can be diagnosed while the fetus is in the uterus.

Newborn infants who have been previously diagnosed with obstruction while still in the uterus can receive prompt surgical correction of the defects, often with good results.

Experimental surgery on the fetus while in the uterus, which can relieve the obstruction or decrease the pressure on the kidney in the fetus, is presently being studied. Future techniques can be expected to salvage better kidney function than the good results that are presently expected.

Symptoms

Signs of hydronephrosis is generally observed during routine fetal ultrasound studies done during routine pregnancies and as such there are no symptoms in the fetus.

In the newborn, any diagnosed urinary tract infection is reason to suspect some type of obstructive problem in the kidney. In the older child, repeat urinary tract infections are cause for evaluation of possible obstruction.