A 68-year-old man comes to the emergency department due to lightheadedness that occurs mainly upon standing. This has gotten worse today. He has fallen on 2 occasions, but he has not sustained any injuries. He has not had any chest pain or pressure, palpitations, or shortness of breath at rest. He has a history of coronary artery disease with a bare metal stent placed in the right coronary artery 2 years ago. His other medical problems include chronic obstructive lung disease, osteoarthritis, benign prostatic hyperplasia, and hypertension.
His medications include clopidogrel, aspirin, metoprolol, atorvastatin, ramipril, and a tiotropium inhaler. The dose of ramipril was increased recently and he was also started on tamsulosin for urinary symptoms. He quit smoking at the time of his stent placement after a 50 pack-year smoking history. He does not drink alcohol.
He does not appear to be in acute respiratory distress. His blood pressure is 97/70 mm Hg, pulse is 112/min and regular, and respirations are 16/min. His oxygen saturation is 98% on room air. His BMI is 20 kg/m². His mucous membranes are moist. The neck veins appear distended while sitting and demonstrate a rapid "x" descent. There is a 4 cm left supraclavicular lymph node which is hard and mobile on palpation. The lungs have scattered expiratory wheezes. There are occasional heart beats that are auscultated at the apex but not felt in the radial pulse. There is 2+ lower extremity edema, more on the right compared to the left.
ECG shows sinus tachycardia, right bundle branch block, low-voltage QRS complexes, and nonspecific ST segment and T wave changes.
Which of the following is the most likely cause of this patient's current symptoms?

Question

Quizplus · Accepted Answer

11ec193a_95b5_cdd9_853d_7b80e1f885f5_MD0002_00 This patient's clinical presentation is suggestive of subacute pericardial tamponade. Tamponade can be acute or subacute. As fluid accumulates, the cardiac chambers become smaller and the pericardium stiffens. The rigid pericardium prevents the left ventricular free wall from expanding and also decreases venous return to the right side. The right ventricle distends at the interventricular septum and bulges to the left, reducing left ventricular compliance and decreasing filling during inspiration. These changes, which likely explain the patient's progressive lightheadedness upon standing, eventually lead to decreased cardiac output with hypotension and tachycardia, along with elevated jugular venous pressure (with rapid "x" descent) and pulsus paradoxus (>10 mm Hg drop in systolic blood pressure with inspiration). Cardiac tamponade can be confirmed with echocardiography, which can also evaluate for right ventricular collapse. Treatment involves prompt removal of the fluid by pericardiocentesis (preferred) or surgery. Malignancy is commonly associated with cardiac tamponade, and this patient's asymmetric leg edema is suggestive of possible deep venous thrombosis (DVT) in the setting of hypercoagulability of malignancy. Combined with his smoking history, lung cancer is a possible etiology in this patient. Malignancy would also explain his hard supraclavicular lymph node. (Choice A) Ischemic cardiomyopathy can present with lightheadedness (possible ventricular arrhythmia or low cardiac output), peripheral edema, and shortness of breath. However, this patient's distended neck veins with rapid "x" descent is more characteristic of tamponade than ischemic cardiomyopathy. Also, his lung examination does not show crackles. (Choice B) Tamsulosin and/or ramipril can cause decreased blood pressure and dizziness, but it is usually not associated with distended neck veins or rapid "x" descent. (Choice D) This patient's asymmetric leg edema and the ECG findings suggest possible pulmonary embolism, but the lack of chest pain or shortness of breath makes a significant pulmonary embolus (enough to cause this degree of hypotension) less likely, although he may have a DVT. (Choice E) Superior vena cava syndrome usually presents with upper extremity and facial edema due to obstruction of the superior vena cava (most commonly due to lung cancer). Hypotension and lower extremity edema are not usually seen. Educational objective: Pericardial tamponade is due to fluid accumulation in the pericardium and causes hypotension by preventing filling of both the left and right ventricles. Classic physical findings of tamponade include pulsus paradoxus, rapid "x" descent in the neck veins, hypotension, and tachycardia. Treatment involves prompt removal of the pericardial fluid, usually with pericardiocentesis. __________ References: Cardiac tamponade (http://www.ncbi.nlm.nih.gov/pubmed/9135828)

A 68-Year-Old Man Comes to the Emergency Department Due to Lightheadedness