From the Guidelines
Rhabdomyolysis is a serious medical condition characterized by the rapid breakdown of skeletal muscle tissue, releasing muscle proteins like myoglobin into the bloodstream, which can damage the kidneys and lead to acute kidney injury, as indicated by elevated creatine kinase (CK) levels above 1,000 U/L 1.
Definition and Pathophysiology
Rhabdomyolysis is a condition where skeletal muscle tissue breaks down rapidly, releasing muscle proteins like myoglobin into the bloodstream. This can lead to acute kidney injury, as the kidneys are overwhelmed by the influx of muscle proteins. The condition can be caused by various factors, including trauma, extreme exertion, medications, infections, or toxins.
Diagnosis and Monitoring
Diagnosis of rhabdomyolysis typically involves monitoring creatine kinase (CK) levels, which are usually elevated above 1,000 U/L and often much higher 1. Plasma myoglobin measurement may also be useful in identifying the risk of acute kidney injury, as it has an earlier peak plasma concentration than CKs 1. Additionally, plasma potassium tests for hyperkalemia and measurements of kidney function by means of plasma creatinine tests can be useful in assessing the condition.
Treatment and Management
Treatment of rhabdomyolysis focuses on addressing the underlying cause and typically involves aggressive intravenous fluid resuscitation with normal saline at rates of 200-300 mL/hour initially to maintain urine output above 200 mL/hour. Electrolyte imbalances, especially hyperkalemia, hypocalcemia, and hyperphosphatemia, must be corrected. In severe cases with kidney failure, dialysis may be necessary. Prevention involves adequate hydration during exercise, careful medication management, and avoiding excessive alcohol or drug use.
Key Considerations
- Early recognition and treatment of rhabdomyolysis significantly improve outcomes and prevent chronic kidney disease.
- Elevated CK levels above 1,000 U/L are a key indicator of rhabdomyolysis 1.
- Plasma myoglobin measurement may be more sensitive and specific than CKs in identifying the risk of acute kidney injury 1.
- Aggressive intravenous fluid resuscitation is crucial in managing rhabdomyolysis, with volumes greater than 6L required in patients with severe rhabdomyolysis (CPK >15,000 IU/L) to prevent acute kidney injury and the need for renal replacement therapy 1.
From the Research
Definition and Causes of Rhabdomyolysis
- Rhabdomyolysis is a medical condition caused by muscle breakdown leading to potential renal damage 2.
- It is characterized by muscle damage and the release of intracellular muscle contents into the circulation 3.
- The etiology of rhabdomyolysis is multifactorial, including exertion, extreme temperature changes, ischemia, infections, immobility, drugs, toxins, endocrine causes, autoimmune reactions, trauma, or genetic conditions 2.
Symptoms and Diagnosis
- Symptoms of rhabdomyolysis can include myalgias, muscle weakness, or dark-colored urine, but often include non-specific symptoms 2.
- The diagnosis is often determined with an elevated creatinine kinase greater than five times the upper-limit of normal 2.
- It is vital that emergency clinicians consider the diagnosis when patients present with circumstances known to be high-risk for rhabdomyolysis, including intoxication, prolonged immobilization, and/or altered mentation 4.
Complications and Treatment
- Severe disease may result in renal failure, electrolyte derangements, liver disease, compartment syndrome, and disseminated intravascular coagulation 2.
- Treatment includes addressing the underlying etiology, as well as aggressive intravenous hydration with a goal urine output of 300 mL/h 2.
- Electrolyte disturbances should always be detected in the early stages and carefully treated, and the use of bicarbonates or diuretics may also be helpful 3.
- Renal replacement therapy should be determined on a case-by-case basis, and may be implemented due to water-electrolyte or acid-base disorders 2, 3.