Hydronephrosis is a condition in which one or both kidneys become swollen due to failure of the urine to drain from the kidney(s) to the bladder. This can occur due to either blockage or backflow of urine.

The common causes of hydronephrosis include kidney stones, swollen prostate gland and prostate cancer in cases involving men, and pregnancy and cancers of the bladder, kidney or reproductive system in women. Hydronephrosis may also develop in an unborn child.

Hydronephrosis may or may not show any symptoms. The most common symptom is severe pain either in the back and side, or between your ribs and hip. Pain usually increases when drinking fluids and may extend towards the groin area. Other symptoms may include nausea, vomiting, fever or shivering (indicating kidney infection), presence of blood in your urine or urinating less often.

Hydronephrosis can be diagnosed with an ultrasound. Your doctor may order other tests such as blood tests, urine tests, intravenous urography (X-ray imaging that detects a special dye injected into the blood stream) and CT scan to confirm the diagnosis. Hydronephrosis in a developing fetus is usually identified during a routine ultrasound scan.

Treatment involves draining urine with the help of a thin tube called a catheter to release the pressure on the kidneys. Once the pressure is relieved, your doctor may perform surgery to treat the underlying cause. Your doctor may release a blockage in the ureter with the placement of a stent through the catheter, remove kidney stones, prescribe antibiotics to fight infections, remove an enlarged prostate gland, or treat cancer with a combination of radiotherapy, chemotherapy and surgery. Hydronephrosis in an unborn child usually resolve on its own.