Unilateral hydronephrosis is swelling of one kidney due to a backup of urine.
Hydronephrosis; Chronic hydronephrosis; Acute hydronephrosis; Urinary obstruction
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.
Common symptoms include:
- Flank pain
- Abdominal mass
- Nausea and vomiting
- Urinary tract infection
- 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 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.
Loss of kidney function may occur if the condition is left untreated.
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 of the disorders that cause this condition will prevent it from occurring.
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.
Reviewed By: Sovrin M. Shah, MD, Assistant Professor, Department of Urology, Albert Einstein College of Medicine, New York, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.