Which of these is a renal or intrarenal cause of acute renal failure?

Which of these is a renal or intrarenal cause of acute renal failure?

• A. Fluid overload and non-cardiogenic edema
• B. Urine outflow obstruction due to an enlarged prostate
• C. Reduced renal blood flow due to shock, dehydration, or vasopressor agents
• D. Nephron injury from trauma, nephrotoxic drugs, or infection

Answer: (D)

Intrinsic (intrarenal) acute kidney injury happens when the kidney tissue itself is damaged. This includes injury to the nephron or renal parenchyma from nephrotoxic drugs, trauma to the kidney, or infection that inflames the kidney (such as acute tubular necrosis, interstitial nephritis, or glomerulonephritis). That explains why nephron injury from trauma, nephrotoxic drugs, or infection is the best fit for an intrarenal cause. By contrast, reduced renal blood flow from shock or dehydration is a prerenal problem—the kidneys are fine structurally but not getting enough blood. Obstruction of urine outflow, such as an enlarged prostate, is a postrenal issue. Fluid overload and non-cardiogenic edema relates to fluid status rather than an intrinsic kidney injury.

Intrinsic (intrarenal) acute kidney injury happens when the kidney tissue itself is damaged. This includes injury to the nephron or renal parenchyma from nephrotoxic drugs, trauma to the kidney, or infection that inflames the kidney (such as acute tubular necrosis, interstitial nephritis, or glomerulonephritis). That explains why nephron injury from trauma, nephrotoxic drugs, or infection is the best fit for an intrarenal cause. By contrast, reduced renal blood flow from shock or dehydration is a prerenal problem—the kidneys are fine structurally but not getting enough blood. Obstruction of urine outflow, such as an enlarged prostate, is a postrenal issue. Fluid overload and non-cardiogenic edema relates to fluid status rather than an intrinsic kidney injury.