Prerenal azotemia is most often caused by dehydration or shock.

Prerenal azotemia is most often caused by dehydration or shock.

• A. Liver disease
• B. Urinary tract infection
• C. Dehydration or shock
• D. Kidney stones

Answer: (C)

Prerenal azotemia happens when the kidneys aren’t receiving enough blood flow, so filtration drops even though the kidney tissue itself is fine. The most common causes are reduced circulating volume or systemic hypoperfusion—dehydration or shock—so this scenario is a direct match. The other options point to problems inside the kidney or urinary tract rather than a perfusion issue: liver disease can affect nitrogen metabolism and BUN levels but doesn’t cause underperfusion of the kidneys; a urinary tract infection is an infectious process in the urinary tract; kidney stones cause obstruction leading to postrenal, not prerenal, azotemia. In prerenal cases you often see a relatively high BUN compared to creatinine and a tendency toward concentrated urine as the kidneys conserve water.

Prerenal azotemia happens when the kidneys aren’t receiving enough blood flow, so filtration drops even though the kidney tissue itself is fine. The most common causes are reduced circulating volume or systemic hypoperfusion—dehydration or shock—so this scenario is a direct match. The other options point to problems inside the kidney or urinary tract rather than a perfusion issue: liver disease can affect nitrogen metabolism and BUN levels but doesn’t cause underperfusion of the kidneys; a urinary tract infection is an infectious process in the urinary tract; kidney stones cause obstruction leading to postrenal, not prerenal, azotemia. In prerenal cases you often see a relatively high BUN compared to creatinine and a tendency toward concentrated urine as the kidneys conserve water.