An acute compartment syndrome occurs when the interstitial tissue pressure rises above the tissue perfusion pressure and causes a cycle of increasing edema and cellular necrosis. Acute compartment syndromes are subdivided into three groups that are related to the time of compartment pressurization: incipient, acute, and established. The end result of an untreated compartment syndrome can be hand and forearm contracture (Volkmann’s ischemic contracture) or tissue loss. Compartment syndromes have a number of causes and can occur in both the hand and forearm.

Maintaining a high index of suspicion for the development of the condition is critical to making the diagnosis. The diagnosis of compartment syndrome can be difficult, especially in cases where the interstitial tissue pressure is rising but does not yet meet the criteria for an established compartment syndrome. It may also be difficult in some clinical settings (e.g., after snakebite envenomation) where the symptoms of envenomation are similar to the symptoms of compartment syndrome.

These injuries are usually a result of a soft-tissue crushing injury (i.e., a roller injury). Cases of compartment syndrome have been reported following open and closed fractures, the application of circumferential casts, arterial laceration and repair (reperfusion), snakebite, external pressurization (drug addict lying on the arm for a prolonged period of time), medical anticoagulation, arterial puncture, hemophilic bleeding, and intraoperative limb positioning.

One of the earliest signs of compartment syndrome is pain out of proportion to the injury. Subsequently, patients describe loss of sensation and motor function. Sometimes, obtunded patients present for evaluation of limb swelling. In these cases an understanding of the conditions likely to be associated with compartment syndrome is valuable. On physical examination, the patient will have a tense swollen hand or forearm. Often the concave appearance of the palm
reverses and becomes convex. The earliest sign is “pain on passive stretch.” Stretching muscles that pass through the compartment is painful for the patient. (For example, stretching the fingers into flexion is painful for patients with a volar forearm compartment syndrome. To test the intrinsic muscles of the hand for pain on passive stretch, place the metaphalangeal joint in extension and passively flex the interphalangeal joint.) Later, patients have abnormality on objective neurologic testing (loss of two-point discrimination and paralysis). Finally, patients lose skin coloration (pallor) and become pulseless. Patients can have a compartment syndrome with palpable pulses.

The diagnosis is often made on the basis of the history and physical examination. Often, however, interstitial tissue pressure measurements are useful in confirming the diagnosis and effective treatment. Interstitial tissue pressures that are within 30 mm Hg of the mean arterial pressure or 20 mm Hg of the diastolic blood pressure are very suggestive of a compartment syndrome.