From the Guidelines
A urinalysis is not necessary to confirm rhabdomyolysis, as the diagnosis can be made based on clinical symptoms and laboratory findings such as elevated serum creatine kinase (CK) levels, typically at least 5 times the upper limit of normal 1. When evaluating a patient with suspected rhabdomyolysis, the focus should be on identifying the condition promptly and initiating treatment to prevent acute kidney injury, which is associated with high morbidity and mortality. Some key points to consider in the diagnosis of rhabdomyolysis include:
- Elevated serum CK levels, which can reach tens of thousands of units per liter 1
- Clinical symptoms such as muscle pain, weakness, and dark urine
- Serum myoglobin levels, which may be more sensitive and specific than CK levels in identifying the risk of acute kidney injury 1
- Laboratory findings such as elevated creatinine, hyperkalemia, hyperphosphatemia, hypocalcemia, and elevated liver enzymes While urinalysis may show myoglobinuria, this finding can be transient or absent depending on timing, and is not a reliable diagnostic tool for rhabdomyolysis. The priority in managing rhabdomyolysis is to prevent acute kidney injury through aggressive IV fluid administration, and to monitor for complications such as hyperkalemia and acute kidney injury 1.
From the Research
Diagnosis of Rhabdomyolysis
- The diagnosis of rhabdomyolysis is confirmed by elevated creatine kinase levels 2, 3, 4, 5.
- Additional testing is needed to evaluate for potential causes, electrolyte abnormalities, and acute kidney injury (AKI) 2.
- Myoglobinuria is a key feature of rhabdomyolysis, and urinalysis may be used to detect myoglobin in the urine 6.
- However, the studies do not specifically state that a urinalysis is required to confirm rhabdomyolysis, but rather that it may be used as part of the diagnostic workup.
Role of Urinalysis in Rhabdomyolysis
- Urinalysis may be used to detect myoglobinuria, which is a characteristic feature of rhabdomyolysis 6.
- The presence of myoglobin in the urine can indicate muscle damage and support the diagnosis of rhabdomyolysis 6.
- However, the absence of myoglobinuria does not rule out the diagnosis of rhabdomyolysis, as the condition can be diagnosed based on elevated creatine kinase levels and other clinical features 2, 3, 4, 5.