Unilateral hydronephrosis

Also known as: Hydronephrosis

Definition

Unilateral hydronephrosis is swelling of one kidney due to a backup of urine.

See also:  Bilateral hydronephrosis

Causes, incidence, and risk factors

Hydronephrosis is a condition that occurs with a disease. It is not a disease itself. Conditions that are often associated with unilateral hydronephrosis include:

• Acute unilateral obstructive uropathy
• Chronic unilateral obstructive uropathy
• Vesicoureteric reflux (backflow of urine from bladder to kidney)
• Nephrolithiasis (kidney stones)
• Hydronephrosis that occurs without a known cause during pregnancy

Unilateral hydronephrosis occurs in approximately 1 in 100 people.

Symptoms

• Flank pain
• Abdominal mass
• Nausea and vomiting
• Urinary tract infection
• Fever
• Painful urination (dysuria)
• Increased urinary frequency
• Increased urinary urgency

Note: Sometimes unilateral hydronephrosis does not have symptoms.

Signs and tests

Unilateral hydronephrosis is usually identified with tests such as the following:

• Abdominal MRI
• CT scan of the kidneys or abdomen
• Intravenous pyelogram (IVP)
• Isotope renography (special scan of the kidneys)
• Ultrasound of the kidneys or abdomen

Treatment

Treatment and prognosis for unilateral hydronephrosis depend on what is causing the kidney swelling. Treatment may include:

• A ureteral stent (tube that allows the ureter to drain into the bladder)
• A nephrostomy tube (allows the blocked urine to drain through the back)
• Antibiotics for infections

Patients who have only one kidney, who have immune-compromising disorders such as diabetes or HIV, or who have received a transplant should be treated promptly.

Preventative antibiotics may be prescribed to decrease the risk of urinary tract infections in patients who have long-term hydronephrosis.

Expectations (prognosis)

Prolonged hydronephrosis results in the eventual loss of kidney function.

Complications

If hydronephrosis is left untreated, the affected kidney may be permanently damaged. Kidney insufficiency or kidney failure is rare with unilateral hydronephrosis because the other kidney usually functions normally. However, if the patient has only one functioning kidney, kidney failure will occur.

Calling your health care provider

Call your health care provider if you have prolonged or severe flank pain, or if you suspect hydronephrosis.

Prevention

Prevention of the disorders associated with unilateral hydronephrosis will prevent this condition.

References

Frøkiaer 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.

See also:

• Disease

  Acute kidney failure

  

  Acute (sudden) kidney failure is the sudden loss of the ability of the kidneys to remove waste and concentrate urine without losing .

• Disease

  Bilateral hydronephrosis

  

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

• Disease

  Reflux nephropathy

  

  Reflux nephropathy is a condition in which the kidneys are damaged by the backward flow of urine into the kidney.

• Disease

  Kidney stones

  

  A kidney stone is a solid mass made up of tiny crystals. One or more stones can be in the kidney or ureter at the same time. See also:

• Disease

  Chronic unilateral obstructive uropathy

  

  Chronic unilateral obstructive uropathy is a condition in which there is long-term blockage of one of the tubes (ureters) that drains urine from the kidneys. See also:

• Disease

  Acute unilateral obstructive uropathy

  

  Acute unilateral is a sudden blockage in one of the tubes (ureters) that drain urine from the kidneys. See also:

Review date:

March 22, 2010

Reviewed by:

Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; Scott Miller, MD, Urologist in private practice in Atlanta, Georgia. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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