A 65-year-old man is brought to the emergency department after a motor vehicle collision. The patient was the restrained front passenger in a car that skidded on ice and hit a tree at 25 miles/hr. His right leg was pinned under the dashboard, and extrication took 2 hours. The patient has severe right leg pain, which is minimally relieved with morphine. He had a myocardial infarction 6 months ago for which he takes aspirin and clopidogrel. Blood pressure is 102/72 mm Hg and pulse is 111/min. On physical examination, the patient is mildly sedated. The right leg appears swollen and bruised. Sensation is intact. Passive movement of the right ankle and toes cause severe pain in the lower leg. Bilateral pedal pulses are palpable. X-ray of the right lower extremity is negative for fracture. Which of the following is the best next step in management of this patient's leg pain?
Acute compartment syndrome of the extremity | |
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*Delta pressure (diastolic pressure − compartment pressure) ≤30 mm Hg is consistent with compartment syndrome. | |
This patient has severe lower extremity pain worsened by passive stretch of the calf muscles (eg, passive movement of the ankle and toes). Given his likely crush injury (eg, leg pinned under dashboard, bruising) and use of antiplatelet medications, which may cause occult bleeding, this presentation is concerning for compartment syndrome (CS) of the lower leg. CS is a limb-threatening condition caused by increased pressure within an enclosed fascial space that limits perfusion of muscle and nerve tissues.
CS is frequently associated with long bone fractures, but other causes include crush injury and arterial reperfusion procedures. Patients on antiplatelet therapy or anticoagulation are at increased risk. Severe pain (classically out of proportion to the injury) that is exacerbated by passive stretch is a classic early feature; other features that typically occur later include loss of sensation, motor weakness, and diminished pulses.
Although CS can be a clinical diagnosis, not all features may be present early in the course, and pain medications may mask the symptoms. Surgeons may choose to confirm the diagnosis and avoid unnecessary fasciotomy by measuring compartment pressures (eg, needle manometry); a delta pressure (diastolic blood pressure − compartment pressure) ≤30 mm Hg is consistent with CS. Definitive management is emergency fasciotomy.
(Choice A) Compression wraps of the calf are typically used for edema caused by chronic venous insufficiency. However, they would increase pressure within the fascial compartments and are not recommended for this patient.
(Choice C) A lower extremity arteriogram is appropriate if there is concern for arterial occlusion, which can cause severe pain due to ischemia. However, this patient's normal pulses make arterial occlusion very unlikely.
(Choice D) Lower extremity CT scan can diagnose an occult fracture but is less urgent than assessing for compartment syndrome in a patient with lower extremity crush injury, swelling, and pain with passive muscle stretch.
(Choice E) Lower extremity venous ultrasound is used primarily to diagnose deep vein thrombosis (DVT). Although DVT can occur following trauma, it usually does not cause such rapid swelling (eg, within 2 hr) or acute, severe pain (eg, unrelieved by narcotic medication).
(Choice F) Lower extremity traction is used for short-term management of fractures and dislocations. It is not useful in CS, and this patient's x-ray does not show a fracture.
Educational objective:
Compartment syndrome is caused by increased pressure within an enclosed fascial space that limits perfusion. Severe pain that increases with passive stretch is a classic early feature. Measurement of compartment pressures can confirm the diagnosis.