A 55-year-old woman with a history of metastatic endometrial adenocarcinoma, total abdominal hysterectomy, and bilateral salpingo-oophorectomy eight months earlier on doxorubicin presented with dyspnea on exertion and tachycardia.
Her symptoms started two days earlier, and worsened when walking up stairs. The patient had a chronic nonproductive cough but no chest pain, palpitations, fever, leg swelling, or calf pain. She did not have orthopnea but had increased pain in her chest when lying flat.
Her vitals included a temperature of 36.8°C, a blood pressure of 161/86 mm Hg, a pulse of 125 bpm, a respiratory rate of 20 bpm, and an oxygen saturation of 99% on room air. She weighed 271 pounds, and was alert, oriented to person, place, and time, and in no acute distress but preferred sitting up in a chair.
She had a regular tachycardia, distant heart sounds, normal S1 and S2, and no murmurs. She had +1 pitting edema to her lower legs and an elevated jugular venous pressure to the mid-neck. Her lungs were clear, and she was in no respiratory distress.
What bedside tests will help make the diagnosis? What is the likely diagnosis?
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Diagnosis: Impending Cardiac Tamponade
Cardiac tamponade occurs when the accumulation of fluid in the pericardial sac (acutely or subacutely) raises intracardiac pressures, resulting in reduced ventricular filling and hemodynamic compromise. (Cardiol Clin. 2017;35:525; http://bit.ly/33cnffj.) The pericardial sac normally contains approximately 50 mL of physiologic fluid, but can hold 80-200 mL acutely and even up to 2 L chronically.
In a normal pericardium, compliance is limited, so a small increase in fluid will cause a steep rise in pericardial pressure. In subacute and chronic pericardial effusions, a slow accumulation of fluid over time allows the pericardium to stretch to its maximal size. (Prog Cardiovasc Dis. 2017;59:380; http://bit.ly/33dX4F9.) With a fixed intrapericardial sac volume, any increase in pericardial fluid raises pericardial pressure, resulting in compression of the cardiac chambers and impeded diastolic filling. (Prog Cardiovasc Dis. 2017;59:380; http://bit.ly/33dX4F9.)
Acute cardiac tamponade occurs within minutes, often from trauma or rupture of the heart or aorta, causing cardiogenic shock. Subacute cardiac tamponade occurs over days to weeks, and is often associated with neoplastic, uremic, and idiopathic pericarditis, with symptoms of dyspnea, chest discomfort, peripheral edema, and fatigability. (UpToDate. July 24, 2019; http://bit.ly/35aRkO6.)
Symptoms of pericardial effusions include chest pain, syncope or presyncope, dyspnea, tachypnea, hypotension, tachycardia, peripheral edema, elevated jugular venous pressure, and pulsus paradoxus. The three classic signs of cardiac tamponade, known as Beck's triad, are low blood pressure, muffled heart sounds, and distended jugular veins. (JAMA. 1935;104:714; http://bit.ly/2IvwIX1.) Cardiac tamponade is suspected with evidence of pericardial fluid with hemodynamic compromise.
The diagnostic approach should seek to establish the presence, quantification, hemodynamic impact, and cause of the effusion. Chest x-rays are often ordered for chest pain and dyspnea, and findings can vary from normal pericardial silhouettes in small effusions to being rounded and flask-like to the classic boot-shaped heart in large effusions. Chest x-rays are neither sensitive nor specific.
Electrocardiograms typically show sinus tachycardia, sometimes low voltage, and whether pericarditis is present. Electrical alternans is specific but not very sensitive for cardiac tamponade, and shows beat-to-beat alterations in the QRS complex, reflecting swinging of the heart in the pericardial fluid. (Curr Cardiol Rep. 2017;19:57.) Echocardiography is the recommended imaging to diagnose a pericardial effusion and is nearly 100 percent accurate. (UpToDate. July 24, 2019; http://bit.ly/35aRkO6.)
Small effusions of 50-100 mL are seen only posteriorly and are typically less than 10 mm thick. Moderate effusions of 100-500 mL are seen along the length of the posterior wall and are 10-20 mm. Large effusions of more than 500 mL are seen circumferentially with fluid measuring more than 20 mm. (Curr Cardiol Rep. 2017;19:57.)
Definitive treatment of cardiac tamponade involves removal of the pericardial fluid. (N Engl J Med. 2003;349:684.) A pericardiocentesis is indicated urgently when there is hemodynamic instability. Fluid restriction and inotropic support will be only temporarily beneficial. (UpToDate. July 18, 2019; http://bit.ly/339NLG8.) Without signs of hemodynamic compromise, observation with serial physical exams and echocardiograms can be performed until more controlled percutaneous drainage can be performed.
Our patient was stable on presentation. Her only abnormal vital signs were tachycardia and tachypnea. The first bedside test was an ECG, which showed a sinus tachycardia at 125 bpm, a normal axis, normal intervals, and no ST or T segment changes. Her ECG did show low voltage and a slight beat-to-beat variation concerning for electrical alternans. We had no prior ECGs to compare. This prompted a bedside ultrasound, which showed a very large pericardial effusion up to 4 cm in diameter with evidence of right atrium and right ventricle inversion. Overall, the echocardiogram was concerning for impending tamponade. Due to hemodynamic stability and an initial concern for pulmonary embolism, a chest CT was also obtained, which was negative.
After the bedside echocardiogram, the patient was still stable, so cardiology was consulted. She was brought to the cardiac catheterization lab for pericardiocentesis with drain placement. A total of 650 mL of serosanguinous fluid were drained and sent for analysis. The patient tolerated the procedure well. The fluid was found to be malignant.
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Dr. Selbyis an assistant professor of emergency medicine at the University of Colorado School of Medicine and the medical director of the forensic nursing program at University of Colorado Hospital in Aurora. Follow her on Twitter@DocSelbs. Read her past columns athttp://bit.ly/EMN-QuickConsult.