A 52-year-old woman comes to the emergency department due to increasing dyspnea and chest tightness over the past 2 weeks. She has a history of stage 4 chronic kidney disease due to chronic glomerulonephritis. Temperature is 36.6 C (97.8 F), blood pressure is 106/82 mm Hg, and pulse is 98/min. Systolic blood pressure decreases by 12 mm Hg during inspiration. Physical examination shows distant heart sounds and clear lungs. Echocardiography in this patient is most likely to reveal which of the following findings?

Question

A 52-year-old woman comes to the emergency department due to increasing dyspnea and chest tightness over the past 2 weeks.  She has a history of stage 4 chronic kidney disease due to chronic glomerulonephritis.  Temperature is 36.6 C (97.8 F), blood pressure is 106/82 mm Hg, and pulse is 98/min.  Systolic blood pressure decreases by 12 mm Hg during inspiration.  Physical examination shows distant heart sounds and clear lungs.  Echocardiography in this patient is most likely to reveal which of the following findings?

Quizplus · Accepted Answer

11ec160b_3a81_a95d_9249_1900706a41ac_MD0001_00 This patient with progressive dyspnea and chest tightness over a period of 2 weeks and a drop in systolic blood pressure >10 mm Hg with inspiration (ie, pulsus paradoxus) likely has subacute cardiac tamponade; uremia in the setting of advanced renal failure can lead to pericarditis with associated pericardial effusion and sometimes tamponade. Tamponade classically presents with Beck's triad of hypotension (often less prominent with subacute compared to acute tamponade), distant heart sounds, and jugular venous distension. Normally, a pressure gradient exists between the vena cava and the right side of the heart, allowing blood to fill the right atrium during diastole. With inspiration, a reduction in intrathoracic pressure pulls additional blood into the right side of the heart and the pulmonary circulation, causing normal inspiratory collapse of the inferior vena cava (IVC). With cardiac tamponade, increasing pericardial pressure begins to compress the relatively low-pressure, right-sided heart chambers and restrict diastolic filling. The increased right-sided pressures are transmitted backward to the vena cava, causing engorgement of the IVC with decreased inspiratory collapse that can be seen on echocardiography. In addition, because the right ventricle is compressed and unable to expand during diastole, the increase in right-sided blood flow during inspiration causes the ventricular septum to bow into the left ventricle; this reduces left ventricular stroke volume during inspiration and is responsible for the observed >10 mm Hg drop in systolic blood pressure. As tamponade progresses, impaired right-sided filling causes the left ventricle to receive less blood, resulting in decreased cardiac output and obstructive shock. Because the obstruction to blood flow is primarily right sided, there is no pulmonary edema and the lungs remain clear to auscultation. (Choices A, B, D, and E) A segmental (eg, apical) wall motion abnormality suggests myocardial ischemia or infarction, dilation of all 4 cardiac chambers is seen with dilated cardiomyopathy, severe tricuspid regurgitation can occur with carcinoid syndrome, and systolic anterior motion of the mitral valve is seen with hypertrophic cardiomyopathy (and often exacerbates obstruction of the left ventricular outflow tract). None of these conditions are expected to cause pulsus paradoxus or distant heart sounds. Educational objective: Cardiac tamponade involves restriction of diastolic filling of the right-sided heart chambers, with engorgement and decreased inspiratory collapse of the inferior vena cava seen on echocardiography. Pulsus paradoxus (>10 mm Hg drop in systolic blood pressure during inspiration) is commonly present with tamponade.

A 52-Year-Old Woman Comes to the Emergency Department Due to Increasing