Acute Kidney Injury (AKI): A Nursing Guide

Acute kidney injury appears constantly in medical-surgical nursing, and recognising it early is often what makes it reversible.

What AKI is

Acute kidney injury (AKI) is a sudden drop in kidney function over hours to days, marked by rising creatinine and BUN and often falling urine output. Unlike chronic kidney disease, AKI is frequently reversible when the cause is caught and corrected early.

The three categories

AKI is classified by where the problem begins — and the category drives treatment:

• Prerenal — reduced blood flow to the kidney (hypovolemia, heart failure, shock). The kidney tissue itself is still intact.
• Intrarenal — direct damage to kidney tissue (acute tubular necrosis, nephrotoxic drugs, prolonged ischemia).
• Postrenal — obstruction of urine outflow after the kidney (renal calculi, an enlarged prostate, tumors).

What the nurse monitors

Track urine output hourly, daily weights, and strict intake and output. Watch potassium closely — hyperkalemia is the most immediately life-threatening complication of AKI and can trigger fatal dysrhythmias. Review every medication for nephrotoxicity and the need for renal dose adjustment.

Key takeaways

• AKI is sudden and often reversible; chronic kidney disease is gradual and permanent.
• Classify as prerenal, intrarenal, or postrenal — it determines the treatment.
• Hyperkalemia is the priority complication to catch and treat.