Kidney Obstruction: Overview

The kidneys are bean-shaped organs, each about the size of your fist, located behind the abdomen (one on each side of the spine).  The kidneys remove waste and extra water from the blood by converting it to urine. They also help keep a stable balance of salts and other substances in the blood.  When a kidney is obstructed, all of these functions can be affected.  Obstruction can also cause pain and lead to serious kidney infections.

Kidney stones that have fallen into the ureter (the drainage tube of kidney) are the most common cause of kidney obstruction.  Small stones in the ureter may pass on their own or may need to be removed.  However, obstruction caused by scar tissue in the ureter often requires more extensive treatment. A ureteropelvic junction (UPJ) obstruction is usually caused by a congenital (at birth) narrowing where the ureter joins the kidney.  A ureteral stricture occurs when scar tissue forms anywhere along the ureter.  Strictures can be caused by passage of stones, diseases around the ureter, and damage during other surgical procedures (see Gynecologic Related Disorders).  In any case, the location and cause of the obstruction are usually determined by CT scan.