acute kidney injury, also called acute renal failure, occurs when an obstruction
in the urinary tract below the kidneys causes waste to build
up in the kidneys . It is not as common as intrinsic acute kidney injury (AKI) or acute tubular necrosis (ATN).
blockage in the
urinary tract may cause urine to build up in one or both kidneys. Over time,
this fluid buildup can prevent the normal flow of urine out of the kidney.
Conditions that may lead to postrenal acute kidney injury include:
- Kidney stones . Kidney stones most often
develop in the
ureters. They may also develop in the
- An enlarged prostate (benign prostatic hyperplasia, or BPH). An enlarged
prostate gland may put pressure on the urethra, causing urine to back up
in the bladder.
- A bladder that doesn't empty properly. This may be
caused by certain nervous system disorders, such as
multiple sclerosis, spinal cord injury, or
- Blood clots in the
ureters or urethra.
- Cancer of the
Postrenal acute kidney injury requires immediate treatment.
When detected early, it usually can be reversed by removing or bypassing the
obstruction in the urinary tract, before any permanent damage to the kidneys
- If the blockage is a
kidney stone, your
doctor can remove or destroy the stone. The most commonly used medical procedure for
kidney stones is
extracorporeal shock wave lithotripsy. This treatment
uses sound waves that pass easily through the body but are strong enough to
break up a kidney stone.
- For a blockage that cannot be removed, your doctor can use a catheter or a
stent to reroute the urine flow around the blockage. Placing a catheter in the bladder to empty it
can quickly relieve symptoms and allow kidney function to return to
Most people regain normal kidney function if the condition is reversed
If the obstruction is not relieved, the waste buildup
and pressure on the kidneys may damage kidney tissue. Acute kidney injury is
much harder to reverse after damage to the kidneys has occurred.