In suspected acute kidney injury, which sequence of assessment steps is appropriate?

• A. Biopsy first
• B. Assess volume status, obtain basic labs (creatinine, BUN), urinalysis, electrolytes, urine output monitoring; determine pre/intrinsic/postrenal causes; imaging if needed; nephrology consult
• C. Imaging only
• D. Start diuretics immediately

Answer: (B)

The key idea is to approach suspected AKI with a careful, stepwise assessment to quickly identify reversible factors and guide management. Begin with evaluating volume status and stabilizing the patient, since many cases are due to reduced kidney perfusion from dehydration or upset hemodynamics. Then gather essential data: basic labs to gauge kidney function (creatinine, BUN), urinalysis to look for clues like protein, blood, casts, or eosinophils, electrolytes to see what the kidneys aren’t handling well, and close monitoring of urine output to quantify injury and assist staging.

With this information you can differentiate the likely categories—pre-renal from hypoperfusion, intrinsic kidney injury such as ATN or glomerulonephritis, or post-renal obstruction—and decide on next steps. If there’s any suspicion of obstruction, imaging (for example, a renal ultrasound) is appropriate to evaluate for hydronephrosis or stones. A renal biopsy is reserved for specific scenarios where a histologic diagnosis would change treatment, not as the initial step in suspected AKI. Diuretics are not routinely started in AKI as an immediate treatment because they don’t fix the underlying injury and can worsen fluid or electrolyte imbalances unless there’s a clear indication like volume overload. This sequence—volume assessment, basic labs and urinalysis with urine output, etiologic clarification, targeted imaging as needed, and nephrology input when indicated—provides the most rational and effective approach.