In rhabdomyolysis, renal function impairment is often due to what complication?

• A. Renal failure due to increased myoglobin levels
• B. Increased red blood cell count
• C. Hyperglycemia due to insulin resistance
• D. Decreased urine production due to dehydration only

Answer: (A)

Rhabdomyolysis causes kidney injury mainly because a large amount of myoglobin is released from damaged muscle and then filtered by the kidneys. Myoglobin can be directly toxic to the renal tubular cells and can form casts that obstruct the tubules, leading to acute kidney injury and sometimes renal failure. Dehydration and low blood flow can worsen this process, but the central issue is the myoglobin load in the kidneys. The other options don’t explain the typical mechanism: increased red blood cells aren’t a feature of rhabdomyolysis, hyperglycemia isn’t characteristic, and renal impairment isn’t caused by dehydration alone—the myoglobin-driven pigment nephropathy is the key factor.