Which of the following is a common cause of acute kidney injury in the ICU?

• A. Acute tubular necrosis from nephrotoxic drugs only
• B. Sepsis-related AKI or ischemic injury from hypotension
• C. Chronic kidney disease
• D. Obstructive uropathy from stones

Answer: (B)

In the ICU, acute kidney injury most commonly arises from impaired renal perfusion and inflammatory injury due to sepsis and hypotension. Sepsis triggers systemic inflammation, vasodilation, capillary leak, and microcirculatory dysfunction, all of which reduce kidney oxygen delivery and disrupt tubular function. Prolonged or severe hypotension compounds this by lowering renal perfusion pressure, leading to ischemic injury of the nephrons. This combination often produces AKI that can start as prerenal azotemia and progress to intrinsic injury such as acute tubular necrosis if the perfusion deficit persists.

Nephrotoxic drugs can contribute to AKI, but they are not the predominant cause in the ICU, and obstructive uropathy from stones or preexisting chronic kidney disease represent different scenarios that are less likely to be the principal cause of new AKI in many ICU patients. Managing AKI in this setting focuses on maintaining adequate perfusion, careful fluid management, timely treatment of sepsis, and avoiding nephrotoxins to protect renal function.