From the Guidelines
Rhabdomyolysis is diagnosed when serum creatine kinase (CK) levels exceed 1000 IU/L, typically five times the upper limit of normal, accompanied by clinical symptoms such as muscle pain, weakness, and dark urine. This diagnostic criterion is supported by recent guidelines for the acute care of severe limb trauma patients, which highlight the importance of monitoring CK levels to reduce morbidity and mortality associated with compartment syndrome 1. The diagnosis of rhabdomyolysis can also be informed by the measurement of plasma myoglobin, which may be more sensitive and specific than CK levels in identifying the risk of acute kidney injury, a common complication of rhabdomyolysis 1.
Key diagnostic criteria for rhabdomyolysis include:
- Serum CK levels greater than 1000 IU/L
- Clinical symptoms such as muscle pain, weakness, and dark urine
- Myoglobinuria, indicated by tea or cola-colored urine
- Elevated serum creatinine, suggesting kidney injury
- Electrolyte abnormalities, including hyperkalemia, hyperphosphatemia, hypocalcemia, and metabolic acidosis
- Elevated liver enzymes, such as AST and ALT, and lactate dehydrogenase (LDH)
It is essential to promptly recognize rhabdomyolysis, as treatment focuses on aggressive IV fluid administration to prevent kidney damage, correction of electrolyte abnormalities, and addressing the underlying cause. Common causes of rhabdomyolysis include trauma, excessive exercise, medications, infections, and prolonged immobility. According to the guidelines, monitoring plasma myoglobin and CK levels, as well as plasma potassium and creatinine tests, can help identify patients at risk of acute kidney injury and inform timely intervention 1.
From the Research
Diagnostic Criteria for Rhabdomyolysis
The diagnosis of rhabdomyolysis is based on a combination of clinical presentation, laboratory findings, and medical history. The key criteria for diagnosing rhabdomyolysis include:
- Muscle damage and the release of intracellular muscle contents into the circulation 2
- Elevated creatine kinase (CK) levels, which confirm the diagnosis 3, 4
- Presence of myoglobinuria, which is a hallmark of the syndrome 3, 5
- Electrolyte abnormalities, such as hyperkalemia and hyperphosphatemia 2, 4
- Acute kidney injury (AKI), which is a common complication of rhabdomyolysis 2, 6, 3, 4
Laboratory Findings
Laboratory findings that support the diagnosis of rhabdomyolysis include:
- Elevated CK levels, which are typically five times higher than the normal value 4
- Increased myoglobin levels, which can be detected in the blood and urine 3, 5
- Elevated lactate dehydrogenase (LDH) levels, which indicate muscle damage 6, 4
- Electrolyte disturbances, such as hyperkalemia and hyperphosphatemia, which can occur due to muscle breakdown 2, 4
Clinical Presentation
The clinical presentation of rhabdomyolysis can vary from mild to severe and may include: