Alternate Names: Hydronephrosis

Causes and Risks:

Hydronephrosis develops when the kidney pelvis and calyces become distended because urine is unable to drain into the bladder. Hydronephrosis is not a separate disease, but a physical phenomenon that occurs with many diseases. Symptoms, treatment, and prognosis are those of the associated diseases.

Disorders associated with unilateral hydronephrosis include:

• Acute unilateral obstructive uropathy
• Chronic unilateral obstructive uropathy
• Vesicoureteric reflux (backflow of urine from bladder to kidney)
• Nephrolithiasis (renal stones)
• Idiopathic hydronephrosis of pregnancy

Unilateral hydronephrosis of varying degrees is discovered in approximately 1 out of 100 people.

Prevention:

Prevention of the causative disorders listed above.

Symptoms:

• Flank pain
• Abdominal mass
• Nausea/vomiting
• Urinary tract infection
• Fever
• Dysuria
• Urinary frequency
• Urinary urgency

Signs and Tests:

Hydronephrosis is discovered by the health care provider as a result of testing. It may be apparent on:

• IVP
• Isotope renography (radio-isotope scan of the kidneys)
• Ultrasound of the kidneys or abdomen
• CT scan of the kidneys or abdomen
• Abdominal MRI

Treatment:

Surgery to remove the blockage may be needed.

If infection is present it should be promptly treated with antibiotics.

If hydronephrosis is chronic, prophylactic antibiotics may be used to decrease the incidence of urinary tract infections.

Prognosis:

Prolonged hydronephrosis results in the eventual loss of kidney function.

Complications:

If untreated, permanent damage can be done to the hydronephrotic kidney.Renal insufficiency or renal failure is rare because the other kidney functions normally in most patients. If hydronephrosis is present in both kidneys, renal insufficiency or renal failure may result.

Call your health care provider if prolonged or severe flank pain, or hydronephrosis is suspected.