Elevated pressures within a confined muscle compartment can lead to functional and circulatory impairment of that limb. The most common compartments affected are in the lower leg and forearm. This syndrome develops as a result of external compressive forces on a limb or from any mechanism that increases the compartmental size and pressure (Table 176-1).
Causes of Compartment Syndrome
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Causes of Compartment Syndrome
|Orthopedic ||Tibial fractures |
|Forearm fractures |
|Vascular ||Ischemic-reperfusion injury |
|Iatrogenic ||Vascular puncture in anticoagulated patients |
|IV/intra-arterial drug injection |
|Constrictive casts |
|Soft tissue injury ||Prolonged limb compression |
|Crush injury |
|Hematologic ||Hemophilia |
|Adverse effects of anticoagulants (warfarin) |
Severe and difficult-to-control pain, pain out of proportion to examination, and pain with passive stretch of the limb are the hallmark symptoms of this disease. Nerve dysfunction often accompanies the pain and causes burning or dysesthesias in the sensory distribution of the nerve. Motor function can be impaired as well. On exam, the compartment is often swollen, firm, and tender to palpation. Since tissue pressure does not typically exceed arterial pressure, the affected limb often has normal distal pulse, temperature, and color. Symptoms can begin within a few hours after the injury or up to 48 hours after the inciting event.
DIAGNOSIS AND DIFFERENTIAL
Diagnosis is largely clinical. Direct measurement of the compartment is necessary when the diagnosis is in question or in patients who are obtunded or sedated. Several commercial devices are available to measure compartment pressures. Normal compartment pressure is < 10 mm Hg. The exact pressure elevation at which cell death occurs is unclear. Pressures between 30 to 50 mm Hg are felt to be detrimental if left untreated for several hours. The diastolic blood pressure minus the measured tissue pressure, or “delta pressure,” better predicts the potential for irreversible muscle damage. A delta pressure of 30 mm Hg is most commonly used to diagnose acute compartment syndrome. Hypotensive patients do not tolerate elevated compartment pressures as well as normotensive patients. The differential diagnosis for compartment syndrome includes other causes of pain, such as fracture, hematoma, or infection, and other causes of neurologic or vascular compromise.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Once the diagnosis is confirmed, surgical fasciotomy is necessary. Admit all patients to the operating room or appropriate inpatient service for observation and serial examinations.
While definitive management is being arranged, administer supplemental oxygen, correct hypotension, remove constrictive casts or dressings, and place the affected limb at the level of the heart.
Reverse anticoagulation in anticoagulated patients, and replace factor levels in hemophiliacs.
Functional outcomes are favorable when diagnosis and treatment of compartment syndrome occurs within 6 hours of its onset. Fasciotomy may be futile if tissue pressures have been elevated to 24 to 48 hours as permanent dysfunction may already be present.
For further reading in Tintinalli's Emergency Medicine: A Comprehensive Study Guide
, 8th ed., see Chapter 278
, “Compartment Syndrome” by Haller