What clinical finding is likely causing fatigue and lethargy in a client with acute kidney failure?

The most relevant clinical finding leading to fatigue and lethargy in a client with acute kidney failure is a decreased hemoglobin level. When the kidneys are not functioning properly, erythropoietin production can decrease, resulting in decreased red blood cell production and subsequently lower levels of hemoglobin. Hemoglobin is essential for transporting oxygen throughout the body, and a decrease in this important protein leads to insufficient oxygen delivery to tissues, causing fatigue and lethargy.

While increased creatinine levels and increased blood urea nitrogen (BUN) levels indicate reduced kidney function and can contribute to overall feelings of malaise, they do not directly address the oxygen-carrying capacity of the blood, which is critical in explaining fatigue specifically. An electrolyte imbalance can also be present in acute kidney failure, but its primary symptoms may include muscle weakness, cardiac issues, or altered mental status rather than direct fatigue. Therefore, decreased hemoglobin is the key factor in this situation, as it directly relates to the client’s energy levels and overall fatigue.