Unilateral hydronephrosis

Alternative Names

Hydronephrosis; Chronic hydronephrosis; Acute hydronephrosis; Urinary obstruction

Definition

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

Causes

Hydronephrosis (kidney swelling) occurs as the result of a disease. It is not a disease itself. Conditions that are often associated with unilateral hydronephrosis include:

Acute unilateral obstructive uropathy
Blockage of a ureter due to scarring, tumor, urinary stones, or congenital abnormalities (present from birth)
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 about 1 in 100 people.

Symptoms

Common symptoms include:

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

In some cases, there may be no symptoms.

Exams and Tests

The condition is found on an imaging test such as:

Treatment

Treatment depends on the cause of 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 out of the body into a drainage bag)
Antibiotics for infections

People who have only one kidney, who have immune system disorders such as diabetes or HIV, or who have had a transplant will need prompt treatment.

People who have long-term hydronephrosis may need antibiotics to reduce the risk of urinary tract infections.

Outlook (Prognosis)

Loss of kidney function may occur if the condition is left untreated.

Possible Complications

If hydronephrosis is left untreated, the affected kidney may be permanently damaged. Kidney failure is rare if the other kidney is working normally. However, kidney failure will occur if there is only one functioning kidney.

When to Contact a Medical Professional

Call your health care provider if you have ongoing or severe flank pain, or fever, or if you think you may have hydronephrosis.

Prevention

Prevention of the disorders that cause this condition will prevent it from occurring.

References

Zeidel ML. Obstructive uropathy. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 125.

SinghI, Strandhoy JW, Assimos DG. Pathophysiology of urinary tract obstruction. In: Wein AJ, ed. Campbell-Walsh Urology. 10th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 40.