A 43-year-old woman comes to the emergency department with acute-onset, left-sided weakness. The patient reports increased fatigue, low-grade fevers, and occasional palpitations over the last 3 months. She has lost 6 kg (13.2 lb) during this period. She has no prior medical conditions and takes no medications. She does not use tobacco, alcohol, or illicit drugs. Temperature is 37 C (98.6 F), blood pressure is 120/76 mm Hg, pulse is 80/min and regular, and respirations are 14/min. There are no carotid bruits. The thyroid is normal in size and there is no tenderness. Cardiac examination shows normal S1 and S2 and a middiastolic rumble at the apex. The lungs are clear on auscultation. Neurologic examination shows left-sided weakness. Laboratory results show a hemoglobin level of 10.2 g/dL and an erythrocyte sedimentation rate of 60 mm/hr. Brain imaging reveals multiple small, acute infarcts in the right parietal and temporal lobes. Transthoracic echocardiography shows a mass in the left atrium. Which of the following is the most likely diagnosis?

Question

A 43-year-old woman comes to the emergency department with acute-onset, left-sided weakness.  The patient reports increased fatigue, low-grade fevers, and occasional palpitations over the last 3 months.  She has lost 6 kg (13.2 lb) during this period.  She has no prior medical conditions and takes no medications.  She does not use tobacco, alcohol, or illicit drugs.  Temperature is 37 C (98.6 F), blood pressure is 120/76 mm Hg, pulse is 80/min and regular, and respirations are 14/min.  There are no carotid bruits.  The thyroid is normal in size and there is no tenderness.  Cardiac examination shows normal S1 and S2 and a middiastolic rumble at the apex.  The lungs are clear on auscultation.  Neurologic examination shows left-sided weakness.  Laboratory results show a hemoglobin level of 10.2 g/dL and an erythrocyte sedimentation rate of 60 mm/hr.  Brain imaging reveals multiple small, acute infarcts in the right parietal and temporal lobes.  Transthoracic echocardiography shows a mass in the left atrium.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec25c8_d8a2_afa4_bc81_af98fd0b76ca_MD0003_00 This patient with acute-onset, left-sided weakness and a left atrial mass identified on echocardiography likely has an atrial myxoma. Myxomas are benign tumors and are the most common primary cardiac neoplasm; approximately 80% arise in the left atrium. Fragments of a left atrial myxoma can embolize into the systemic circulation, leading to stroke or other acute ischemia (eg, limb, mesenteric). Left atrial myxomas frequently obstruct blood flow from the left atrium to the left ventricle, leading to a murmur mimicking that of mitral stenosis (ie, middiastolic rumble at the apex). The obstruction can also lead to decreased cardiac output that manifests as dyspnea, lightheadedness, or syncope. Because the mass is typically mobile, obstructive symptoms may be transient and influenced by position (ie, mitral obstruction is exacerbated by upright posture but is alleviated by lying down); tumor movement occasionally causes a characteristic "tumor plop" sound at the end of diastole on auscultation. In addition, some myxomas can produce cytokines (eg, IL-6) that lead to systemic inflammation (evidenced by an elevated erythrocyte sedimentation rate) and constitutional symptoms (eg, fever, weight loss). The diagnosis is typically established by echocardiography. Prompt surgical resection is recommended to minimize the risk of embolization and sudden cardiac death (due to impaired cardiac output). echocardiography (Choice A) Although infective endocarditis can cause fever, weight loss, and systemic embolization, echocardiography typically shows valvular vegetations rather than an intracardiac mass in the atrium (as seen in this patient). In addition, infective endocarditis typically causes a regurgitant rather than stenotic murmur. (Choice C) Left atrial thrombus can develop in atrial fibrillation and lead to systemic embolization. However, this patient's history of low-grade fevers, weight loss, and elevated erythrocyte sedimentation rate are more consistent with myxoma. (Choice D) Myxomatous valve degeneration is the pathologic cause of mitral valve prolapse, which characteristically produces a midsystolic click rather than middiastolic rumble. (Choice E) Worldwide, rheumatic heart disease is the most common cause of mitral stenosis, which produces a middiastolic rumble and can lead to atrial fibrillation and left atrial thrombus with systemic embolization. However, rheumatic heart disease is uncommon in developed countries. In addition, mitral stenosis typically develops years after the initial episode of rheumatic fever; recurrent episodes are rare in adults and usually involve pharyngitis. Educational objective: Myxomas are the most common primary cardiac neoplasm and usually arise in the left atrium. Fragments of the tumor can dislodge and lead to systemic embolization (eg, stroke, acute limb ischemia). The tumors may also cause position-dependent obstruction of the mitral valve, leading to a middiastolic murmur and symptoms of decreased cardiac output (eg, dyspnea, syncope). Constitutional symptoms (eg, fever, weight loss) may also be present. References: Central nervous system manifestations of cardiac myxoma. (http://www.ncbi.nlm.nih.gov/pubmed/17698701) Clinical presentation of left atrial cardiac myxoma. A series of 112 consecutive cases. (http://www.ncbi.nlm.nih.gov/pubmed/11388092)

A 43-Year-Old Woman Comes to the Emergency Department with Acute-Onset