What is the difference between crush syndrome and rhabdomyolysis in terms of management and treatment?

Crush Syndrome vs Rhabdomyolysis: Key Differences

Crush syndrome is the systemic manifestation of traumatic rhabdomyolysis—rhabdomyolysis is the muscle breakdown itself, while crush syndrome is the life-threatening systemic consequence that includes acute kidney injury, hyperkalemia, hypovolemic shock, and compartment syndrome. 1

Conceptual Distinction

Rhabdomyolysis is the disintegration of striated muscle resulting in release of muscle cell contents (myoglobin, creatine kinase, potassium, phosphate) into the extracellular fluid. 2 This can occur from numerous causes—both physical (trauma, prolonged immobilization, excessive exercise) and non-physical (drugs, toxins, infections, metabolic disorders). 2

Crush syndrome specifically refers to traumatic rhabdomyolysis with systemic complications following prolonged compression of muscle tissue, typically from entrapment under collapsed structures during earthquakes, building collapses, or mass casualty events. 1, 3 The critical difference is that crush syndrome implies a specific traumatic etiology with predictable systemic sequelae requiring disaster-specific management protocols. 4

Clinical Spectrum Differences

Rhabdomyolysis Presentation

• Can range from asymptomatic elevation in creatine kinase to severe acute tubular necrosis and multiorgan failure 2
• May present with isolated muscle symptoms without systemic involvement
• Serum creatine kinase elevation is the hallmark finding 2

Crush Syndrome Presentation

• Always involves systemic manifestations including hypovolemia from massive third-spacing into damaged muscle compartments 1
• Develops compartment syndrome due to increased intra-compartmental pressure from tissue edema 1
• Presents with the "6 Ps": pain, paresthesia, paresis, pain with passive stretch, pink color (initially), and pulselessness 5, 6
• Acute kidney injury from myoglobinuric nephropathy is the defining life-threatening complication 1
• Life-threatening hyperkalemia occurs even before extrication from entrapment 1

Critical Management Differences

Rhabdomyolysis Management

• Vigorous hydration with isotonic saline followed by alkaline solutions and mannitol 2
• Standard fluid resuscitation protocols apply
• Treatment can often be initiated after hospital arrival
• For mild cases, oral hydration may be sufficient 6

Crush Syndrome Management: Time-Critical Field Intervention

The fundamental management difference is that crush syndrome requires immediate pre-hospital fluid resuscitation starting while the victim is still trapped, not after extrication. 5

Pre-Hospital (Field) Management

• Start IV fluids immediately upon locating the victim, even while still trapped under rubble, with 0.9% normal saline at 1000 ml/hour initially 5
• If no vein is accessible, use an intra-osseous needle in a lower limb 5
• Reduce infusion rate by at least 50% (to ≥500 ml/hour) if extrication takes longer than 2 hours 5
• This pre-hospital intervention is unique to crush syndrome and not applicable to general rhabdomyolysis 1

Hospital Management

• Administer 3-6 liters of 0.9% normal saline in the first 24 hours with target urine output of 200-300 ml/hour until myoglobinuria clears 5
• Patients arriving within 40 hours with adequate initial fluid resuscitation (>10,000 mL/2 days) have significantly lower rates of renal failure (25% vs 100%) 7
• Renal failure is highly associated with massive muscle damage (creatine kinase >25,000 U/L) and insufficient initial fluid resuscitation 7

Critical Pitfalls Specific to Crush Syndrome

• Never triage crush victims away from active treatment due to lack of dialysis availability—intensive fluid management can restore renal function and avoid dialysis need entirely 5
• Avoid limb elevation if compartment syndrome is suspected, as it worsens compartment ischemia by reducing perfusion pressure 5, 6
• Do not use mannitol before adequate volume resuscitation, as it can worsen renal injury in hypovolemic patients 5
• Failure to recognize crush injury early misses the critical 6-hour window when intensive fluid resuscitation may prevent acute kidney injury 5
• Current evidence does not support active alkalinization over aggressive fluid resuscitation alone 5

Prognostic Differences

Crush syndrome carries higher mortality (up to 20%) due to the combination of traumatic injury, prolonged entrapment, delayed rescue, and systemic complications including hyperkalemia-induced cardiac arrest before or immediately after extrication. 8 Standard rhabdomyolysis from non-traumatic causes has variable mortality depending on etiology and severity but generally lower than disaster-related crush syndrome when modern medical care is accessible.