When this happens, pressure builds up in the tissues and muscles causing tissue ischemia. An increase in muscle weight will reduce the compartment volume of the surrounding fascial borders and result in an increased compartment pressure. An increase in the pressure of the tissue can force fluid to leak into the interstitial space (extracellular fluid), leading to a disruption of the micro-circulation of the leg. This condition occurs commonly in the lower leg and various other locations within the body, such as the foot or forearm. CECS can be seen in athletes who train rigorously in activities that involve constant repetitive actions or motions. Pathophysiology
In a normal human body, blood flow from the arterial system (higher pressure) to venous system (lower pressure) requires a pressure gradient. When this pressure gradient is diminished, blood flow from the artery to the vein is reduced. This causes a backup of blood and excessive fluid to leak from the capillary wall into spaces between the soft tissues cells, causing swelling of the extracellular space and a rise in intracompartmental pressure. This swelling of the soft tissues surrounding the blood vessels compresses the blood and lymphatic vessels further, causing more fluid to enter the extracellular spaces, leading to additional compression. The pressure continues to increase due to the non-compliant nature of the fascia containing the compartment. This worsening cycle can eventually lead to a lack of sufficient oxygen in the soft tissues (tissue ischemia) and tissue death (necrosis).
The most common cause of acute compartment syndrome is fracture of a bone, most commonly the tibia. There is no difference between acute compartment syndrome originating from an open or closed fracture. Leg compartment syndrome is found in 2% to 9% of tibial fractures. It is strongly related to fractures involving the tibial diaphysis as well as other sections of the tibia. Direct injury to blood vessels can lead to compartment syndrome by reducing the downstream blood supply to soft tissues. This reduction in blood supply can cause a series of inflammatory reactions that promote the swelling of the soft tissues. Such inflammation can be further worsened by reperfusion therapy. Because the fascia layer that defines the compartment of the limbs does not stretch, a small amount of bleeding into the compartment, or swelling of the muscles within the compartment, can cause the pressure to rise greatly. Intravenous drug injection, casts, prolonged limb compression, crush injuries, anabolic steroid use, vigorous exercise, and eschar from burns can also cause compartment syndrome. Patients on anticoagulant therapy have an increased risk of bleeding into a closed compartment.Abdominal compartment syndrome occurs when the intra-abdominal pressure exceeds 20 mmHg and abdominal perfusion pressure is less than 60 mmHg. This disease process is associated with organ dysfunction and multiple organ failures.