A 25-year-old man comes to the emergency department due to a sudden onset of left foot pain. The pain started suddenly an hour ago, when he was sitting at his desk, and has progressed gradually. He has no history of similar episodes or recent trauma to his left leg. On review of systems, the patient admits to tiredness and some weight loss over the last 2 months, which he attributes to stress. He has no significant medical history. He is a college student. The patient does not use tobacco, alcohol, or illicit drugs. His mother was diagnosed with "a blood clot" after elective knee-replacement surgery. Temperature is 37.2 C (99 F), blood pressure is 122/81 mm Hg, pulse is 86/min, and respirations are 14/min. Examination shows clear lung fields and a regular rhythm, with a low-pitched diastolic murmur over the cardiac apex. The abdomen is soft and nontender, with no palpable masses. Examination of the extremities reveals adequate bilateral femoral pulses. The left popliteal and dorsalis pedis pulses are absent. The left foot appears pale and is cooler than the right. Sensations on the left foot are intact, and the patient is able to voluntarily move the limb. There is no tenderness on palpation of the lower left leg or foot. Neurologic examination is within normal limits. Which of the following is the most likely cause of this patient's condition?
A)Abdominal aortic aneurysm
B)Bicuspid aortic valve
C)Factor V Leiden heterozygosity
D)Hypertrophic cardiomyopathy
E)Left atrial myxoma

Question

A 25-year-old man comes to the emergency department due to a sudden onset of left foot pain.  The pain started suddenly an hour ago, when he was sitting at his desk, and has progressed gradually.  He has no history of similar episodes or recent trauma to his left leg.  On review of systems, the patient admits to tiredness and some weight loss over the last 2 months, which he attributes to stress.  He has no significant medical history.  He is a college student.  The patient does not use tobacco, alcohol, or illicit drugs.  His mother was diagnosed with "a blood clot" after elective knee-replacement surgery.  Temperature is 37.2 C (99 F), blood pressure is 122/81 mm Hg, pulse is 86/min, and respirations are 14/min.  Examination shows clear lung fields and a regular rhythm, with a low-pitched diastolic murmur over the cardiac apex.  The abdomen is soft and nontender, with no palpable masses.  Examination of the extremities reveals adequate bilateral femoral pulses.  The left popliteal and dorsalis pedis pulses are absent.  The left foot appears pale and is cooler than the right.  Sensations on the left foot are intact, and the patient is able to voluntarily move the limb.  There is no tenderness on palpation of the lower left leg or foot.  Neurologic examination is within normal limits.  Which of the following is the most likely cause of this patient's condition?
A)Abdominal aortic aneurysm
B)Bicuspid aortic valve
C)Factor V Leiden heterozygosity
D)Hypertrophic cardiomyopathy
E)Left atrial myxoma

Quizplus · Accepted Answer

Explanation: This patient has acute-onset pain, diminished pulses, and paleness and coolness of the left foot, which are consistent with acute arterial occlusion. Acute arterial occlusion can occur due to an embolus from a proximal source, acute thrombosis of an atherosclerotic plaque, or direct trauma to the involved artery. The sudden onset of symptoms in this young, previously asymptomatic patient is most consistent with an embolus. Most emboli originate from a cardiac source, and may occur due to atrial fibrillation, severe ventricular dysfunction, endocarditis, valvular disease, atrial myxoma, or a prosthetic valve. This patient has a regular heart rhythm with an apical diastolic murmur, making left atrial myxoma the most likely cause of the embolus. Atrial myxomas are the most common primary cardiac tumors, with the majority occurring in the left atrium. The tumors are typically pedunculated with a stalk coming from the atrial septum, and can be extremely friable, sometimes leading to the release of tumor emboli into the systemic circulation. Some large tumors can present with signs and symptoms of mitral valve obstruction (causing a diastolic murmur and "tumor plop"), rapidly worsening heart failure, and new-onset atrial fibrillation. The diagnosis is confirmed by echocardiography (transesophageal preferred over transthoracic), and prompt surgical excision is typically indicated. (Choice A) An abdominal aortic aneurysm can thrombose and lead to systemic embolization. However, because an abdominal aortic aneurysm typically results from atherosclerosis, it is unlikely to be present in this young patient. (Choice B) A bicuspid aortic valve can undergo accelerated calcification leading to aortic stenosis, typically in patients age >40. Small pieces of calcification may embolize but would be very unlikely to cause total limb arterial occlusion. (Choice C) Factor V Leiden heterozygosity is associated with increased risk for venous thrombosis (eg, deep, cerebral, or mesenteric venous thrombosis). However, it rarely leads to arterial thrombosis or emboli as seen in this patient. (Choice D) Hypertrophic cardiomyopathy causes left ventricular outflow obstruction, leading to a systolic (rather than a diastolic) murmur on physical examination, and is not associated with embolic events. Educational objective: Left atrial myxomas are the most common cardiac tumors and can present with signs and symptoms of mitral valve obstruction (eg, diastolic murmur and "tumor plop"), rapidly worsening heart failure, and new-onset atrial fibrillation. Myxomas frequently embolize systemically, leading to acute arterial occlusion in otherwise healthy patients. References: Clinical presentation of left atrial cardiac myxoma. A series of 112 consecutive cases. (http://www.ncbi.nlm.nih.gov/pubmed/11388092)

A 25-Year-Old Man Comes to the Emergency Department Due to a Sudden