Symptoms of Rhabdomyolysis
Rhabdomyolysis presents with a classic triad of muscle pain, muscle weakness, and dark (tea-colored) urine, though not all symptoms may be present in every case. 1
Key Clinical Manifestations
Primary Symptoms
Muscle symptoms:
- Muscle pain (myalgia), particularly in proximal muscles
- Muscle weakness
- Muscle tenderness
- Muscle swelling
- Cramping
- Fatigue
Urinary changes:
- Dark, tea-colored or cola-colored urine (due to myoglobinuria)
- Decreased urine output in severe cases
Associated Symptoms
- Generalized weakness
- Fatigue
- Fever
- Malaise
- Nausea and vomiting
- Confusion (in severe cases)
- Abdominal pain
Severity Spectrum
Rhabdomyolysis presents on a clinical spectrum ranging from:
- Asymptomatic cases with only elevated creatine kinase (CK) levels
- Mild cases with muscle pain and minimal systemic symptoms
- Severe cases with acute kidney injury, electrolyte abnormalities, and multi-organ dysfunction 2
Laboratory Findings
Key diagnostic findings include:
- Creatine kinase (CK) elevation: Typically at least 10 times the upper limit of normal 2
- Myoglobinuria: Presence of myoglobin in urine causing dark coloration
- Electrolyte abnormalities:
- Hyperkalemia (elevated potassium)
- Hypocalcemia (decreased calcium)
- Hyperphosphatemia (elevated phosphate)
- Elevated inflammatory markers
- Elevated liver enzymes (AST, ALT) due to muscle breakdown
- Elevated creatinine and BUN in cases with kidney involvement
Serious Complications
Acute Kidney Injury
The most significant and life-threatening complication of rhabdomyolysis is acute kidney injury, which occurs in 13-50% of cases. 3
Other Complications
- Compartment syndrome: Characterized by the "6 P's" - pain, paresthesia, paresis, pain with stretch, pink color, and late findings of pulselessness and pallor 1
- Severe electrolyte disturbances: Particularly hyperkalemia which can cause cardiac arrhythmias
- Disseminated intravascular coagulation (DIC)
- Metabolic acidosis
Special Considerations
When to Suspect Rhabdomyolysis
- After trauma or crush injuries
- Following intense exercise, especially in untrained individuals
- In patients on statin medications with severe muscle symptoms
- In patients with unexplained acute kidney injury
- In patients with dark urine and muscle pain
Common Pitfalls
- Misdiagnosis: Rhabdomyolysis may be misdiagnosed as a psychiatric condition when patients present with dark urine and muscle pain 4
- Delayed diagnosis: Failure to recognize the condition early can lead to preventable kidney injury
- Inadequate fluid resuscitation: Aggressive fluid therapy is crucial to prevent kidney damage
- Failure to identify and remove the underlying cause
High-Risk Groups
- Athletes undergoing intense training
- Military recruits and police trainees
- Patients on certain medications (statins, antipsychotics)
- Patients with crush injuries or prolonged immobilization
- Individuals with underlying metabolic myopathies
Early recognition and prompt management of rhabdomyolysis are essential to prevent serious complications, particularly acute kidney injury, which significantly increases morbidity and mortality.