From the Guidelines
A creatine kinase (CK) level above 60,000 U/L indicates severe rhabdomyolysis, requiring immediate hospitalization for aggressive intravenous fluid resuscitation and close monitoring to prevent acute kidney injury and other complications. According to the KDIGO guidelines 1, the initial diagnosis of acute kidney injury (AKI) is based on a rise in creatinine levels or decreased urine output, and patients with severe rhabdomyolysis are at high risk of developing AKI. The guidelines emphasize the importance of early detection and staging of AKI, which can be done using the KDIGO criteria (Table 1) 1.
Key Considerations
- Aggressive intravenous fluid resuscitation with normal saline at 200-300 mL/hour initially, adjusted based on urine output (targeting >200 mL/hour)
- Continuous cardiac monitoring, strict input/output measurements, and frequent electrolyte checks (especially potassium, calcium, and phosphorus)
- Urine alkalinization with sodium bicarbonate (150 mEq in 1L D5W) to maintain urine pH >6.5
- Discontinuation of medications that could worsen muscle breakdown (statins, fibrates, colchicine)
- Close monitoring for signs of acute kidney injury and other complications, with dialysis considered if necessary
Rationale
The KDIGO guidelines 1 provide a framework for the diagnosis and staging of AKI, which is essential for managing patients with severe rhabdomyolysis. By following these guidelines and taking a proactive approach to preventing AKI and other complications, clinicians can improve outcomes for patients with severe rhabdomyolysis. The emphasis on early detection and staging of AKI, as well as the use of aggressive fluid resuscitation and other supportive measures, is critical for reducing morbidity and mortality in these patients 1.
From the Research
Creatine Kinase (CK) Levels and Rhabdomyolysis
- CK levels can range from 10,000 to 200,000 or higher in rhabdomyolysis, with higher levels indicating greater renal damage and associated complications 2
- A case report described a patient with exceptionally high CK levels (nearly 1 million) caused by combined etiologic factors and complicated with acute renal failure 2
Exercise-Induced CK Elevation and Renal Function
- Serum CK levels can increase significantly after exercise, with some individuals experiencing levels above 10,000 U/L, but this does not necessarily lead to renal impairment 3
- A study found that exertional muscle damage produced by eccentric exercise in healthy individuals can cause profound CK elevations without renal impairment 3
Peak CK Levels and Clinical Significance
- Peak CK levels can indicate rhabdomyolysis, a risk factor for acute kidney injury (AKI), and are an independent risk factor for AKI 4
- Older patients are more likely to develop AKI at lower CK levels, and CK levels commonly peak within 1-2 days after admission 4
Urine Output and Creatinine Elevation
- Urine output criteria may be more sensitive in identifying acute kidney injury than traditional serum creatinine criteria, and low urine output is associated with subsequent acute kidney injury and mortality 5
- A study found that low urine output (<0.2 mL · kg-1 · h-1) is independently associated with mortality, even in the absence of acute kidney injury by creatinine elevation 5