Everyone experiences a decline in kidney function with age, some more than others. In certain cases—usually as a result of diabetes or high blood pressure—loss of function can be extreme and lead to chronic kidney disease. Chronic kidney disease develops over months or years—sometimes silently—and affects more than 20 million Americans.

But now, experts are warning people—especially older adults—about the rising number of cases of another kind of kidney disease—acute kidney injury (AKI). AKI develops quickly, causing a sudden and severe drop in kidney function. The number of Americans who each year experience severe AKI that requires dialysis has more than doubled in the past decade. AKIs killed nearly 39,000 Americans in 2009, up from 18,000 in 2000.

AKI Causes

AKI most often targets people over 60 and strikes for a variety of reasons. It's most commonly set off by

  • serious infections,
  • major surgery (especially open-heart procedures),
  • heart failure and
  • exposure to certain drugs.

Patients who have chronic renal failure (CRF) also are at increased risk for suffering acute kidney injury.

AKI is a widespread problem in hospitals. Studies show that 5 percent of all hospital patients develop AKI—a figure that may climb as high as 23 percent in intensive care units. The most common cause of AKI among hospitalized patients is sepsis, a severe reaction to bacterial infection—another scourge in hospitals. Likewise, up to 30 percent of patients who undergo cardiac surgery develop AKI.

Any direct harm to a kidney—such as trauma from an accident or a serious burn—can bring on this dangerous condition as well. Blood clots, dehydration and urinary-tract blockages can place the kidneys in immediate peril, too.

In September 2014, the U.S. Food and Drug Administration (FDA) approved the first test to help detect AKI risk in critically ill patients. Other diagnostic tests are only able to determine whether patients already have the condition. The new test, called NephroCheck, allows for closer monitoring of patients at high risk for developing AKI in the 12 hours following administration of the test—helping to prevent permanent kidney damage.

Loss of Kidney Function

The kidneys are a pair of bean-shaped, fist-sized organs located in the lower back, on either side of the spine. Think of the kidneys as your body's filtration system: As blood passes through them, the kidneys sift out waste products and excess fluid, which are removed from the body and come out in the urine. The kidneys also produce various hormones that help regulate blood pressure, make red blood cells and maintain healthy bones.

AKI causes an abrupt and dramatic drop in the kidneys' filtering capacity, causing waste products and fluid to accumulate in the blood, which can occur over a period of days—or hours. A patient who lacks working kidneys must undergo dialysis, a procedure that filters the blood (either by being connected to an artificial kidney or through a special process in which blood is cleaned inside the body).

A Doctor's Viewpoint

Karl L. Womer, MD, Associate Professor of Medicine Clinical Director, Transplant Nephrology Johns Hopkins Medicine

About 30 percent of all AKI cases requiring dialysis are a result of increasing use of cardiac catheterization and ventilators, and the rise of hospital-acquired infections and acute heart failure. More research is needed to determine what’s responsible for the remaining 70 percent. Also, many people don't initially realize they have kidney disease—the kidneys are remarkably resilient, and it's possible for them to function normally at about half capacity with few or no symptoms.

By the time damage is discovered, it can be severe enough to require dialysis permanently or, if caught early enough, only temporarily until the kidneys heal and return to normal function. Regular follow-up with your doctor, who can monitor your kidney function, is very important.

Source: Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50; Updated by Remedy Health Media

Publication Review By: the Editorial Staff at Healthcommunities.com

Published: 11 Jul 2013

Last Modified: 23 Sep 2014