Review Question - QID 214550

This patient is presenting with acute compartment syndrome (paresthesias, pain with passive stretch of the affected limb, and a "wood-like" or tense compartment in the left leg). The diagnostic study of choice is compartment pressure measurement.

Acute compartment syndrome is increased pressure within a muscle compartment that is formed by surrounding fascia. Acute compartment syndrome typically presents after trauma, especially with long bone fractures. It is more likely to affect young men, which may be due to their relatively larger muscle mass within the surrounding fascia. As the compartment pressure increases, it restricts perfusion of oxygen and nutrients to the affected area, increasing the risk of cellular anoxia to both neural and muscle tissue. Compartment pressures within 10-30 mmHg of diastolic pressure have been shown to compromise perfusion. Patients present with pain out of proportion to an apparent injury, paresthesias, pain with passive stretch of a muscle, and a tense and "wood-like" feeling in the affected limb. Patients can develop motor weakness within 2-4 hours of acute compartment syndrome. If not emergently treated with fasciotomy, compartment syndrome may result in the need for possible limb amputation. Measuring compartment pressures confirms the diagnosis when the pressure is > 30 mmHg or the delta pressure (diastolic blood pressure - compartment pressure) is < 20-30 mmHg.

Incorrect Answers:
Answer 1: Arterial Doppler ultrasound of the left leg may demonstrate arterial insufficiency as the compartment pressure increases. This study would demonstrate a complication of acute compartment syndrome but does not confirm the diagnosis.

Answer 3: Creatine kinase level may be elevated from muscle injury secondary to elevated compartment pressures; however, the diagnosis is not made by laboratory studies, and an elevated creatine kinase level is not specific to compartment syndrome.

Answer 4: Repeat radiography of the left leg is not necessary. Radiography would demonstrate the fracture but would not identify the elevated compartment pressures leading to this patient's new symptoms.

Answer 5: Venous Doppler ultrasound of the left leg may demonstrate inadequate venous drainage from the elevated compartment pressure but would not reveal the diagnosis.

Bullet Summary:
Compartment pressure measurement > 30 mmHg or delta pressure < 20-30 mmHg confirms the diagnosis of acute compartment syndrome.