From the Guidelines
Rhabdomyolysis (Rhabdo) is a serious medical condition characterized by the breakdown of muscle tissue, leading to the release of myoglobin and other muscle cell contents into the bloodstream.
Key Features of Rhabdomyolysis
- Elevated CPK levels: Raising CPK levels above five times normal (approximately 1000 IU/L) is a sign of rhabdomyolysis 1
- Myoglobin release: Myoglobin is responsible for intraluminal kidney tubular obstruction resulting in reduced glomerular filtration rate 1
- Risk of acute kidney injury: High CPK levels (above 75,000 IU/L) are associated with a high incidence of newly formed acute kidney injury (>80%) 1
Detection and Prevention of Acute Kidney Injury
- Repeated bio-assessment: Combining plasma myoglobin, plasma creatine phosphokinase (CPK) and kalaemia measurements to detect acute kidney injury 1
- Bladder catheterisation: Monitoring hourly urine output and urine pH, which should be maintained at 6.5 1
- Volume resuscitation: Administering volumes greater than 6L 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 Pathophysiology of Rhabdomyolysis
- Rhabdomyolysis is a syndrome involving the breakdown of skeletal muscle, causing myoglobin and other intracellular proteins and electrolytes to leak into the circulation 2.
- It is characterized by destruction of skeletal muscle with release of intracellular contents into the bloodstream, including electrolytes, enzymes, and myoglobin 3.
- The rapid breakdown of skeletal muscle with release of electrolytes, myoglobin, and other proteins into the circulation is a key feature of rhabdomyolysis 4.
Clinical Presentation and Diagnosis
- The clinical presentation of rhabdomyolysis encompasses a spectrum of patients ranging from those with asymptomatic increases in creatine kinase (CK) levels to those with fulminant disease complicated by acute kidney injury (AKI), severe electrolyte abnormalities, compartment syndrome, and disseminated intravascular coagulation 4.
- Rhabdomyolysis is diagnosed by elevations in serum creatine phosphokinase (CPK), and while there is no established serum level cut-off, many clinicians use five times the upper limit of normal (approximately 1000 U/l) 2.
- A CK level at least 10 times the upper limit of normal typically is considered diagnostic, as is myoglobinuria 4.
Complications and Treatment
- Rhabdomyolysis can be complicated by acute renal failure (occurring in 4%-33% of patients), compartment syndrome, cardiac dysrhythmias via electrolyte abnormalities, and disseminated intravascular coagulopathy 2.
- The mainstay of treatment is hospitalisation with aggressive intravenous fluid (IVF) resuscitation with the correction/prevention of electrolyte abnormalities 2.
- Management consists of rapidly initiating aggressive intravenous saline resuscitation to maintain a urine output of at least 300 mL/hour, and sodium bicarbonate can be used for patients who are acidotic, and mannitol can be used for those whose urine output is not at goal 4.
- Early recognition and management of rhabdomyolysis is crucial to preserving renal function and preventing life-threatening complications 5, 6.