Cardiac tamponade

Cardiac tamponade, also known as pericardial tamponade, is when fluid in the pericardium (the sac around the heart) builds up, resulting in compression of the heart. Onset may be rapid or gradual. Symptoms typically include those of cardiogenic shock including shortness of breath, weakness, lightheadedness, and cough. Other symptoms may relate to the underlying cause.Apical ultrasound image of the heart in a person with cardiac tamponade. Note how the right atrial collapses during systole.Ultrasound image of the inferior vena cava (IVC) in a person with cardiac tamponade. Note that the IVC is large and changes minimally with breathing. Cardiac tamponade, also known as pericardial tamponade, is when fluid in the pericardium (the sac around the heart) builds up, resulting in compression of the heart. Onset may be rapid or gradual. Symptoms typically include those of cardiogenic shock including shortness of breath, weakness, lightheadedness, and cough. Other symptoms may relate to the underlying cause. Common causes of cardiac tamponade include cancer, kidney failure, chest trauma, and pericarditis. Other causes include connective tissues diseases, hypothyroidism, aortic rupture, and complications of cardiac surgery. In Africa, tuberculosis is a relatively common cause. Diagnosis may be suspected based on low blood pressure, jugular venous distension, pericardial rub, or quiet heart sounds. The diagnosis may be further supported by specific electrocardiogram (ECG) changes, chest X-ray, or an ultrasound of the heart. If fluid increases slowly the pericardial sac can expand to contain more than 2 liters; however, if the increase is rapid as little as 200 mL can result in tamponade. When tamponade results in symptoms, drainage is necessary. This can be done by pericardiocentesis, surgery to create a pericardial window, or a pericardiectomy. Drainage may also be necessary to rule out infection or cancer. Other treatments may include the use of dobutamine or in those with low blood volume, intravenous fluids. Those with few symptoms and no worrisome features can often be closely followed. The frequency of tamponade is unclear. One estimate from the United States places it at 2 per 10,000 per year. Onset may be rapid (acute) or more gradual (subacute). Signs of cardiac tamponade typically include those of cardiogenic shock including shortness of breath, weakness, lightheadedness, and cough. Other symptoms may relate to the underlying cause. Other general signs of shock (such as fast heart rate, shortness of breath and decreasing level of consciousness) may also occur. However, some of these signs may not be present in certain cases. A fast heart rate, although expected, may be absent in people with uremia and hypothyroidism. Cardiac tamponade is caused by a large or uncontrolled pericardial effusion, i.e. the buildup of fluid inside the pericardium. This commonly occurs as a result of chest trauma (both blunt and penetrating), but can also be caused by myocardial rupture, cancer, uremia, pericarditis, or cardiac surgery, and rarely occurs during retrograde aortic dissection, or while the person is taking anticoagulant therapy. The effusion can occur rapidly (as in the case of trauma or myocardial rupture), or over a more gradual period of time (as in cancer). The fluid involved is often blood, but pus is also found in some circumstances. Causes of increased pericardial effusion include hypothyroidism, physical trauma (either penetrating trauma involving the pericardium or blunt chest trauma), pericarditis (inflammation of the pericardium), iatrogenic trauma (during an invasive procedure), and myocardial rupture. One of the most common settings for cardiac tamponade is in the first 24 to 48 hours after heart surgery. After heart surgery, chest tubes are placed to drain blood. These chest tubes, however, are prone to clot formation. When a chest tube becomes occluded or clogged, the blood that should be drained can accumulate around the heart, leading to tamponade.