What is the most common cause of acute kidney injury in the emergency department?

The most common cause of acute kidney injury (AKI) in the emergency department is prerenal azotemia due to hypovolemia or dehydration. This condition occurs when there is a decrease in blood flow to the kidneys, which can result from factors such as inadequate fluid intake, excessive fluid loss from conditions like vomiting, diarrhea, or hemorrhage.

In the context of acute kidney injury, the kidneys respond to reduced perfusion pressure by activating mechanisms to conserve fluid and maintain glomerular filtration rate. When presented in an emergency setting, clinicians often encounter patients who are in a state of hypovolemia or dehydration, especially those presenting with sepsis, trauma, or other acute illnesses. Early recognition and treatment of this prerenal cause of AKI are critical, as reversing the underlying volume status can restore kidney function rapidly.

In contrast, intrinsic renal damage, which refers to actual damage to the renal parenchyma, usually takes longer to develop and may not be as prevalent as prerenal causes in the emergency setting. Postrenal obstruction, caused by urinary tract blockages, can occur but is often less common than prerenal causes. Diuretic use can contribute to AKI, but it typically plays a secondary