Which scenario is most consistent with prerenal acute kidney injury?

• A. Dehydration causing volume depletion and decreased renal perfusion.
• B. Urinary tract obstruction.
• C. Glomerulonephritis.
• D. Chronic kidney disease.

Answer: (A)

Prerenal AKI happens when the kidneys aren’t getting enough blood flow, so filtration drops even though the kidney tissue itself isn’t damaged. Dehydration causes volume depletion, which lowers effective circulating volume and renal perfusion. In this situation the kidneys respond by conserving water and sodium to preserve volume, leading to concentrated urine and typically a low sodium excretion. If perfusion improves, kidney function can recover; continued poor perfusion can progress to intrinsic injury.

The other scenarios involve problems within the kidney or urinary tract: obstruction is a postrenal issue causing backpressure after the kidneys; glomerulonephritis is intrinsic renal injury from inflammation of the glomeruli; chronic kidney disease is a long-standing loss of nephron function, not an acute drop in blood flow. So dehydration with reduced renal perfusion best fits prerenal AKI.