What is the most common cause of acute kidney injury (AKI)?

The most common cause of acute kidney injury (AKI) is pre-renal causes, such as dehydration. This type of AKI occurs when there is a decrease in blood flow to the kidneys, leading to a reduction in the glomerular filtration rate (GFR). Dehydration can significantly lower blood volume, resulting in decreased perfusion of the kidneys. Inadequate blood supply causes the kidneys to be unable to filter waste effectively, which ultimately leads to elevated levels of creatinine and other waste products in the blood.

Pre-renal causes of AKI are often reversible if the underlying issue, like dehydration, is promptly addressed. In contrast, obstructive causes and post-renal causes typically involve obstruction of the urinary tract or other factors that impede urine outflow, which can sometimes take longer to identify and treat. Renal causes related to medications can also contribute to AKI but are less common than pre-renal causes, particularly in acute settings. Thus, pre-renal factors, particularly related to volume depletion, emerge as the most frequent contributing factors to AKI in clinical practice.