Crush injury

A crush injury is injury by an object that causes compression of the body.^[1][2] This form of injury is rare in normal civilian practice, but common following a natural disaster.^[3] Other causes include industrial accidents, road traffic collisions, building collapse, accidents involving heavy plant, disaster relief or terrorist incidents.^[4]

Crush injury
Specialty	Emergency medicine

Presentation

Complications

• Hypovolaemic shock. Loss of plasma volume across damaged cell membranes and capillary walls can lead directly to severe hypovolaemia.^[4] Shock can develop from myocardial depression following release of intracellular electrolytes. In addition, as a result of the mechanism of injury, blood loss from pelvic or long bone fractures may also co-exist.
• Hyperkalaemia and electrolyte imbalance. Disruption of cell membranes can result in a significant release of potassium, which is a largely intracellular cation that can precipitate cardiac arrest. Sequestration of plasma calcium into injured tissue can lead to a relative hypocalcaemia, which may worsen disruption of clotting abilities and shock. Metabolic acidosis may result from reperfusion injury and hypoperfusion related to shock.
• Compartment syndrome. Compartment syndrome is a common complication of crush injury as a consequence of oedematous tissue injury, redistribution of fluid into the intracellular compartment and bleeding. Established compartment syndrome may result in worsened systemic crush syndrome and irreversible muscle cell death.^[4]
• Acute kidney injury. Release of myoglobin by injured muscle leads to rhabdomyolysis coupled with shock leads to a significant rate of acute kidney injury, estimated as up to 15%.^[5] Acute kidney injury leads to a significantly higher mortality.

Pathophysiology

Crush syndrome is a systemic result of skeletal muscle injury and breakdown and subsequent release of cell contents.^[4] The severity of crush syndrome is dependent on the duration and magnitude of the crush injury as well as the bulk of muscle affected. It can result from both short-duration, high-magnitude injuries (such as being crushed by a building) or from low-magnitude, long-duration injuries such as coma or drug-induced immobility.^[4]

Treatment

Early fluid resuscitation reduces the risk of kidney failure, reduces the severity of hyperkalaemia and may improve outcomes in isolated crush injury.^[4]

For casualties with isolated crush injury who are haemodynamically stable, large-volume crystalloid fluid resuscitation reduces the severity of and reduces the risk of acute kidney injury.^[5]

See also

• Crush syndrome