Obstructive uropathy involves a blockage of the flow of urine, causing it to back up and injure one or both kidneys.

Obstructive uropathy occurs when urine cannot drain through a ureter (a tube that carries urine from the kidneys to the bladder). Urine backs up into the kidney and causes it to become swollen (hydronephrosis).

Obstructive uropathy is grouped according to whether it affects one or both kidneys and whether it occurs suddenly or is long term:

• Chronic unilateral obstructive uropathy - Long-term uropathy that affects one kidney
• Chronic bilateral obstructive uropathy - Long-term uropathy that affects both kidneys
• Acute unilateral obstructive uropathy - Sudden uropathy that affects one kidney
• Acute bilateral obstructive uropathy -Sudden uropathy that affects both kidneys

Common causes of obstructive uropathy include the following:

• Urinary tract stones
  • Ureteral stones
  • Bladder stones
• Urinary tract tumors
• Retroperitoneal fibrosis
• Benign prostatic hyperplasia (enlarged prostate)
• Tumors of nearby organs
• Colon cancer
• Cervical cancer
• Uterine cancer
• Any cancer that spreads
• Idiopathic hydronephrosis of pregnancy

Symptoms associated with obstructive uropathy vary depending on whether the obstruction is acute or chronic, whether it is unilateral or bilateral, whether it is complete or partial, and what caused it. Common symptoms of obstructive uropathy include the following:

• Flank pain
  • Bilateral or unilateral
  • Colicky or severe
• Urinary tract infection
• Fever
• Difficulty or pain while urinating
• Nausea or vomiting
• Renal failure
• Weight gain or swelling (edema)
• Decreased urine output
• Blood in the urine

The diagnosis of obstructive uropathy is made on imaging studies. Common radiographic studies used to diagnose obstructive uropathy include:

• Abdominal ultrasound
• Abdominal CT scan
• Intravenous pyelogram (IVP)
• Voiding cystourethrogram
• Renal nuclear scan