A 30-year-old woman presented to her family physician with increasing shortness of breath over the past 2 weeks. Prior to this, she had a flu-like illness and felt like she never recovered. She denied chest pain and edema, did not take any medications, and had not had any recent trauma or surgery. She had a normal examination. Her chest radiograph showed a classic globular heart as demonstrated in Figure 49-1. She had nonspecific ST changes on her ECG. An echocardiogram confirmed pericardial effusion (Figure 49-2). The underlying etiology was not elucidated and she recovered spontaneously over the next several months.
Globular cardiac silhouette or classic “water-bottle heart” seen with a pericardial effusion can be difficult to distinguish from cardiomegaly on plain radiographs. (Courtesy of Heidi Chumley, MD.)
Echocardiogram showing right ventricular (RV) compression from a pericardial effusion (PE). LV, Left ventricle; RA, right atrium. (Courtesy of Heidi Chumley, MD.)
Pericardial effusions are commonly found in the general population and the incidence increases with age. They can be caused by cardiac disease or surgery, connective tissue disorders, neoplasms, infections, renal disease, hypothyroidism, or medications; however, a cause is identified only 50% of the time. The definitive diagnosis is made by echocardiography.
Pericardial effusion, acute or chronic, occurs when there is increased production or decreased drainage of pericardial fluid allowing accumulation in the pericardial space.
The underlying etiology is apparent clinically approximately 25% of the time and can be determined with testing in another 25% of cases, leaving 50% of cases idiopathic.4 Most idiopathic cases have small effusions. Moderate to large pericardial effusions have an identifiable cause in 90%.5
Underlying causes include:
- Congestive heart failure from other cardiac diseases, such as rheumatic heart disease, cor pulmonale, or cardiomyopathy.6
- After cardiac surgery or after a myocardial infarction.2
- Connective tissue disorders (scleroderma, lupus erythematosus, rheumatoid arthritis).6
- Neoplasms: benign (atrial myxoma); primary malignant (mesothelioma); secondary malignant (i.e., lung or breast cancer).6
- Chronic renal disease (uremia or hemodialysis) or other causes of hypoalbuminemia.
- Infections: acute (enterovirus, adenovirus, influenza virus, Streptococcus pneumonia, Coxiella burnetii—responsible for Q fever) or chronic (tuberculosis, fungus, parasites).4
- Medications (procainamide, hydralazine) or after radiation.6
- Severe hypothyroidism with myxedema.6
Clinical features, chest radiograph, and electrocardiogram suggest pericardial effusion, which is confirmed by echocardiogram. The underlying etiology is identifiable in approximately 50% of cases.
Signs and symptoms occur when the volume of fluid is large enough to affect hemodynamics. This occurs at 150 to 200 mL in acute pericardial effusion. Chronic pericardial effusion allows stretching overtime and may require up to 2 L to cause significant symptoms:6
- Hypotension, increased jugular venous pressure, and soft heart sounds form the classic triad of acute cardiac tamponade, but all three are present only in approximately 30% of cases.6
- Common symptoms include anorexia (90%), dyspnea (78%), cough (47%), and chest pain (27%).6
- Common physical examination findings include pulsus paradoxus (77% with acute tamponade, 30% with chronic effusions), sinus tachycardia (50%), jugular venous distention (45%), hepatomegaly and peripheral edema (35%).6
Laboratory and Ancillary Testing
- Electrocardiogram is abnormal in 90%. Findings include low QRS voltage and nonspecific ST-T changes (59% to 63%) and electrical alternans (0% to 10%).6
When the diagnosis remains unclear, pericardial fluid can be sent for cell count and differential, protein, lactate dehydrogenase, glucose, Gram stain, bacterial cultures, fungal cultures, mycobacterial acid-fast stain and culture, and tumor cytology. Measure rheumatoid factor, antinuclear antibody, and complement levels when collagen vascular disease is suspected.6 Check HIV status in at-risk patients.
When there is no obvious cause, ordering this set of specific tests determined the underlying etiology more often than seen in historic controls (27.3% vs. 3.9%; p <0.001).7
- Aerobic and anaerobic blood cultures.
- Throat swab cultures for influenza, adenovirus, and enterovirus.
- Serologic tests for Cytomegalovirus, influenza, C. burnetii, Mycoplasma pneumonia, and Toxoplasma.
- Blood tests for antinuclear antibody (ANA) and thyroid-stimulating hormone (TSH).
- Chest radiograph shows a globular enlarged cardiac silhouette (Figure 49-1) (sensitivity 78%, specificity 34% with moderate or severe effusions) and pericardial fat stripe (Figure 49-3) (sensitivity 22%, specificity 92%).6
- Echocardiography is the preferred imaging test. Echo can be used to quantify volume of pericardial effusion (correlation to amount of fluid withdrawn 0.7).8 Echo-free, as opposed to echogenic fluid, is associated with a lower risk of constrictive pericarditis or recurrent pleural effusion.9
- CT scanning, typically done for another purpose, can demonstrate the presence of a pericardial effusion, but does not qualify volume as well as echocardiography (correlation to amount of fluid withdrawn 0.4).8
Moderate pericardial effusion is seen as a wide pericardium (arrow). (Courtesy of Heidi Chumley, MD.)
Prognosis depends on the underlying cause.
In a study of older adults undergoing echocardiography for reasons other than a pericardial effusion, patients with an incidental small pericardial effusion had a higher 1-year mortality (26%) than did patients without an effusion (11%).10
Follow-up is based on the underlying cause. Pericardial effusions often disappear when the underlying illness resolves, and reappear when the underlying illness does not resolve (metastatic cancer).