Nearly 200,000 people are affected with compartment syndrome each year in the United States.1 Although there are many causes, the clinical pathway in the development of this syndrome is the same.
Muscle groups in the body are surrounded by fascial sheaths that enclose the muscles within a defined space or compartment. When an injury occurs to the muscles within a compartment, swelling ensues. Because the tight fascial sheaths allow little room for expansion, the pressure within the compartment begins to increase. Eventually, blood flow is compromised, and irreversible muscle injury follows. One must suspect a compartment syndrome early to prevent contracture deformities (e.g., Volkmann ischemic contractures) that result from ensuing muscle and nerve necrosis.
The most common locations for compartment syndrome are the forearm and leg.1 Other sites that have been implicated include the hand, shoulder, back, buttocks, thigh, abdomen, and foot. A discussion specific to these muscle compartments is included elsewhere in the text.
In approximately 70% of cases, compartment syndrome develops after a fracture and half of those are caused by tibia fractures.2 Other commonly associated fractures include the humeral shaft, the bones of the forearm, and supracondylar fractures in children.3,4 Other causes of acute compartment syndrome include crush injury, constrictive dressings/casts, seizures, intravenous infiltration, snakebites, infection, prolonged immobilization, burns, acute arterial occlusion or injury, and exertion.2,5 A venous tourniquet can produce compartment syndrome in as little as 90 minutes if it is accidentally left in place.6 Patients with a coagulopathy (e.g., oral anticoagulant use, hemophilia) are at increased risk and may develop compartment syndrome after minimal trauma.
The diagnosis of compartment syndrome is primarily a clinical one. Patients will exhibit pain out of proportion to the underlying injury, sensory symptoms, and muscle weakness. Pain is the earliest and most consistent sign. It is usually persistent and not relieved by immobilization. It is critical that the emergency physician recognizes this condition by its early features, before other signs and symptoms develop, to prevent permanent injury.
Pain that is aggravated by passive stretching is the most reliable sign of compartment syndrome.7 Diminished sensation is the second most sensitive examination finding for compartment syndrome. Sensory examination of the nerves coursing through the affected compartments will reveal diminished two-point discrimination or light touch. Both of these tests are more sensitive than pinprick. Palpation of the compartment will disclose tenderness and "tenseness" over the ischemic segments. The distal pulses and capillary filling may be entirely normal in a patient with significant muscle ischemia; therefore, these findings should not be used to rule out the existence of compartment syndrome.
To summarize, disproportionate pain is the earliest symptom, whereas pain with passive stretching of the involved muscles is the most sensitive sign of compartment syndrome. Paresthesias or hypesthesias ...