Bilateral hydronephrosis is the enlargement (distention) of the urine collecting structures and pelvis of both kidneys. Bilateral means both sides.

See also: Unilateral hydronephrosis

Bilateral hydronephrosis occurs when urine is unable to drain from the kidney down the ureters into the bladder. Hydronephrosis is not itself a disease, but rather a physical result of whatever disease is keeping urine from draining out of the kidneys, ureters, and bladder.

Disorders associated with bilateral hydronephrosis include:

• Acute bilateral obstructive uropathy
• Bladder outlet obstruction
• Chronic bilateral obstructive uropathy
• Neurogenic bladder
• Posterior ureteral valves
• Prune belly syndrome
• Uteropelvic junction obstruction
• Vesicoureteric reflux

Signs of hydronephrosis are generally seen during pregnancy ultrasound studies. There are no symptoms in the fetus.

In the newborn, any urinary tract infection is reason to suspect some type of obstructive problem in the kidney. An older child who gets repeat urinary tract infections should be evaluated for possible obstruction.

Urinary tract obstruction usually has no other symptoms beyond an increased number of urinary tract infections.

Bilateral hydronephrosis may be seen on:

• CT scan of the abdomen or kidneys
• IVP
• Pregnancy (fetal) ultrasound
• Renal scan
• Ultrasound of the abdomen or kidneys

Placing a Foley catheter may relieve the obstruction. Other treatment options include draining the bladder or relieving pressure with nephrostomy tubes placed through the skin (percutaneous) or stents placed in the ureters to allow urine to flow from the kidney to the bladder.

Once the blockage is treated, the underlying cause (such as an enlarged prostate) must be identified and treated.

Advances in fetal ultrasound have given specialists the ability to diagnose problems caused by bilateral obstruction of the urinary tract in the developing fetus. If an obstruction is detected in a fetus, intrauterine surgery (performed while the fetus is still inside the mother's uterus), or shortly after birth, will improve kidney function.

Newborns diagnosed with obstruction while still in the uterus can receive prompt surgical correction of the defects, often with good results.

Renal insufficiency or failure may develop as a complication of many of the disorders associated with hydronephrosis.

This disorder is usually discovered by the health care provider.

A fetal ultrasound can reveal an obstruction of the urinary tract and allow for early surgery with better outcomes in the newborn. Other causes of obstruction, such as kidney stones, can be diagnosed early if individuals recognize early warning signs of obstruction and kidney disease.

Pais VM, Strandhoy JW, Assimos DG. Pathophysiology of urinary tract obstruction. In: Wein AJ, ed. Campbell-Walsh Urology. 9th ed. Philadelphia, Pa: Sauders Elsevier; 2007: chap 37.

Hsu THS, Streem SB, Nakada SY. Management of upper urinary tract obstruction. In: Wein AJ, ed. Campbell-Walsh Urology. 9th ed. Philadelphia, Pa: Sauders Elsevier; 2007: chap 38.

Elder JS. Obstruction of the urinary tract. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th Ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 540.

Frokiaer J, Zeidel ML. Urinary tract obstruction. In: Brenner BM, ed. Brenner and Rector's The Kidney. 8th ed. Philadelphia, Pa; Saunders Elsevier; 2007: chap 35.