A 65-year-old man with persistent atrial fibrillation comes to the emergency department with a cold right foot. He has not been compliant with anticoagulation therapy. His other medical problems include type 2 diabetes mellitus, hypertension, and chronic nephropathy with low-grade proteinuria. The patient's blood pressure is 122/70 mm Hg and pulse is 112/min and irregular. Physical examination shows a cold right leg with absent dorsalis pedis and posterior tibial pulses. An emergency arteriogram reveals right popliteal artery occlusion, which is treated with thrombus aspiration with good angiographic results. Two hours later, the patient has intense pain in the right leg, accompanied by an "ant crawling" and burning sensation. Which of the following is the most likely diagnosis?
A)Compartment syndrome
B)Deep-tissue infection
C)Diabetic neuropathy
D)Ischemic stroke
E)Phantom pain

Question

A 65-year-old man with persistent atrial fibrillation comes to the emergency department with a cold right foot.  He has not been compliant with anticoagulation therapy.  His other medical problems include type 2 diabetes mellitus, hypertension, and chronic nephropathy with low-grade proteinuria.  The patient's blood pressure is 122/70 mm Hg and pulse is 112/min and irregular.  Physical examination shows a cold right leg with absent dorsalis pedis and posterior tibial pulses.  An emergency arteriogram reveals right popliteal artery occlusion, which is treated with thrombus aspiration with good angiographic results.  Two hours later, the patient has intense pain in the right leg, accompanied by an "ant crawling" and burning sensation.  Which of the following is the most likely diagnosis?
A)Compartment syndrome
B)Deep-tissue infection
C)Diabetic neuropathy
D)Ischemic stroke
E)Phantom pain

Quizplus · Accepted Answer

Explanation: 11ec2b69_c113_4a4e_8f63_4763b8c26b14_MD0005_00 This patient, with severe pain following a lower-extremity thrombectomy, has features suspicious for postischemic compartment syndrome (CS). CS is typically associated with traumatic injuries of the extremities, especially long-bone fractures, but may occur in any condition that causes increased pressure in a confined tissue space and compromises blood flow. Postischemic CS is due to interstitial edema and possibly intracellular swelling following tissue ischemia and subsequent reperfusion. Nerve and muscle injury in CS can result in permanent loss of function. Measurement of tissue pressures is diagnostic: Compartment pressure >30 mm Hg or delta pressure (diastolic blood pressure - compartment pressure) <20-30 mm Hg indicates significant CS. If compartment pressures are improving, patients may be observed closely. However, patients with elevated compartment pressures that do not improve rapidly require fasciotomy to avoid long-term complications. (Choice B) Deep-tissue infection, such as necrotizing fasciitis, is also characterized by severe pain out of proportion to obvious clinical signs. Commonly implicated organisms include group A streptococci and mixed anaerobic infections. Symptoms evolve generally over several hours to days and are usually associated with signs of significant systemic toxicity. (Choice C) Diabetic neuropathy may cause chronic lower-extremity pain and paresthesias; acute episodes are not characteristic. (Choice D) Thromboembolic stroke is a common complication of inadequately anticoagulated atrial fibrillation. Characteristic features include acute neurological deficits such as hemiparesis or aphasia, but pain is not typical. (Choice E) Phantom pain refers to perceived pain in an extremity following amputation. It is caused by afferent pain fibers that previously served the affected limb. Educational objective: Compartment syndrome is caused by increased tissue pressures in a confined space leading to impaired perfusion. It is common following traumatic injuries, but can also occur in nontraumatic settings such as arterial occlusion and reperfusion. References: Reperfusion and compartment syndromes: strategies for prevention and treatment. (http://www.ncbi.nlm.nih.gov/pubmed/11400086)

A 65-Year-Old Man with Persistent Atrial Fibrillation Comes to the Emergency