Acute Kidney Injury: What Every Clinician Should Know

New York, NY
April 12, 2007

An international network of kidney and critical care specialists dedicated to shedding light on acute kidney injury has developed a new set of consensus recommendations for the terminology, diagnostic criteria, and staging of acute kidney injury, a poorly-understood condition that can have deadly consequences.

“Acute kidney injury is a major problem with profound consequences that has long been under-recognized,” says Dr. Ravindra L. Mehta of the University of California, San Diego. “Our collective attention has been on chronic kidney disease, and rightfully so. However, we are beginning to realize that acute kidney injury may be a precursor to CKD, and CKD can also lead to AKI.”

At the National Kidney Foundation Spring Clinical Meetings here, Mehta will present findings from two international, multidisciplinary meetings devoted to learning about AKI and improving how it’s treated during session #272 entitled More than ATN: It’s Acute Kidney Injury from 3 PM to 5 PM today.

“We found that there is no uniform approach to this disease, because we had no uniform definition of it,” Mehta notes. Accordingly, participants decided to change the name of the condition, previously known as acute renal failure, or ARF, to acute kidney injury, reasoning that the condition does not always result in renal failure. Since this decision, the term AKI is appearing more commonly in medical publications, Mehta says.

Still, Mehta says that many physicians remain unaware of the profound consequences AKI can have. For instance, evidence suggests that even small increases in serum creatinine can lead to a variety of adverse outcomes that increase both morbidity and mortality. “Because of AKI’s pronounced consequences, we should be considering it as a systemic disease,” Mehta says. “And that’s a paradigm shift.”

Currently, there are many preclinical studies of AKI underway, “but translation of those findings to humans has been stymied, so our progress in this field is limited,” Mehta says. Accordingly, the AKIN recommends five key areas for future research, including studies examining the epidemiology, outcomes, and treatment of the disease. “AKI is an international problem and one that, by its very nature, requires multidisciplinary input. We must work together.”

AKIN recommendations include:

  • Diagnostic criteria for AKI : An abrupt (within 48 hours) reduction in kidney function currently defined as an absolute increase in serum creatinine of > 0.3 mg/dl ( > 25 micromole/L), a percentage increase of 50% or a reduction in urine output (documented oliguria of < 0.5 ml/kg/hr for > 6 hours)

Classification/Staging System for AKI

 

Stage

Creatinine Criteria

Urine Output Criteria

1

 

↑ Serum Creatinine of >0.3 mg/dl or increase to ≥150% - 200% from baseline

<0.5ml/kg/hr for > 6hr

2

Increase serum creatinine to > 200%-300% from baseline

<0.5ml/kg/hr for >12 hrs

3

Increase serum creatinine to >300% from baseline (or serum creatinine ≥4.0mg/dl with an acute rise of at least 0.5 mg/dl)

<0.3ml/kg/hr x 24 hrs or anuria x 12 hr

 

To learn more about the National Kidney Foundation or the Spring Clinical Meetings visit www.kidney.org.