The muscle groups of the extremities are divided into multiple compartments that are formed by strong fascial membranes. Acute compartment syndrome (ACS) occurs when there is an increase in tissue pressure within the closed fascial space leading to compromise of the circulation and function of the tissues within that space (Hammerberg, 2023). Delayed recognition and treatment of compartment syndrome is catastrophic and can lead to significant nerve dysfunction, muscle loss, and myonecrosis leading to rhabdomyolysis, acute renal failure, and irreversible ischemic endpoints including foot drop, irreversible nerve injury, or paralysis (Klingensmith et al., 2008).

The causes of ACS include long bone fracture, tightly applied casts/dressings, critical limb ischemia with reperfusion, burn or crush injury, spontaneous hematoma, soft tissue injuries, non-traumatic myonecrosis/myositis/rhabdomyolysis, or massive volume resuscitation (Hammerberg, 2023). 

ACS is a surgical emergency and patients at risk for developing ACS should be identified early and examined frequently. Early surgical intervention (ideally within four hours of symptom onset) is critical, as this can save the extremity.  Assessment and identification of “the Five P’s” is commonly used to aid in the diagnosis. These include:

• Pain: Pain out of proportion to the injury and with passive motion of the involved muscle is the most common presenting symptom of ACS. A patient may have an increasing or disproportionate demand for narcotics and poor response to appropriate doses of analgesia.
• Paresthesias: Paresthesias in the distribution of the nerves that traverse the affected compartment is another early sign of ACS.
• Paralysis
• Pallor
• Pulselessness

*Paralysis, pallor, and pulselessness are late signs of ACS and represent irreversible soft tissue injury (Klingensmith et al., 2008).
 
Additional clinical features of ACS include tense/firm compartment, increase in extremity girth, acidosis or hyperkalemia following reperfusion of the extremity, and clinical evidence of rhabdomyolysis (Hammerberg, 2023).

ACS is a clinical diagnosis based on patient history, injury, presentation, and clinical suspicion. In some cases when the clinical presentation and/or physical examination are uncertain or in a patient who is unresponsive, compartment pressures can be measured to aid in diagnosis. Compartment pressures are typically measured with a handheld manometer and should be measured in each compartment. Compartment pressures reading within 30mmHg of the diastolic blood pressure with equivocal physical examination warrants surgical intervention (Klingensmith et al., 2008).

ACS is a surgical emergency and once clinical suspicion is raised the patient should have emergent surgical consultation and proceed to the operating room for a fasciotomy. All external pressure on the affected extremity should be removed, including casts, dressing, splints or any other restrictive coverings. A four-compartment fasciotomy is the only recognized treatment of ACS; it involves surgical incision of all four compartments of the lower extremity to allow for decompression (Modrall, 2023).

ACS is a surgical emergency and requires prompt recognition and treatment in order to reduce morbidity and need for amputation.

References
Hammerberg , M. (2023, March 9). Acute compartment syndrome of the extremities. UptoDate. https://www.uptodate.com/contents/acute-compartment-syndrome-of-the-extremities

Klingensmith, M., Chen, L. E., Glasgow, S., Goers, T., & Melby , S. (2008). The Washington Manual of Surgery (5th ed., p. 593). Lippincott Williams and Wilkins.

Modrall, J. G. (2023, January 10). Lower extremity fasciotomy techniques. UptoDate. https://www.uptodate.com/contents/lower-extremity-fasciotomy-techniques