Which of the following is a pre-renal cause of AKI?

The correct answer identifies a narrowing of the renal artery as a pre-renal cause of acute kidney injury (AKI). This condition, known as renal artery stenosis, results in reduced blood flow to the kidneys. The renal arteries supply blood that is crucial for kidney function, and when they are narrowed, it can lead to inadequate perfusion. This decreased blood supply prevents the kidneys from receiving enough oxygen and nutrients, which is essential for their functioning.

In cases of pre-renal AKI, the damage is typically not intrinsic to the kidney tissue itself but rather due to the insufficient blood flow leading to compromised kidney function. Addressing the underlying issue, such as restoring blood flow or managing blood pressure, often helps to restore kidney function.

In contrast, kidney stones, high blood sugar levels, and bladder cancer may lead to intrinsic or post-renal causes of AKI. Kidney stones can obstruct urine flow, causing increased pressure within the urinary tract, while high blood sugar can lead to diabetic nephropathy, which is an intrinsic cause. Bladder cancer may create obstructions or complications that result in AKI, but again, this falls under the category of secondary effects rather than a direct pre-renal cause.