A 66-year-old woman comes to the office due to worsening chest discomfort and shortness of breath for the past 4 weeks. There is no history of recent upper respiratory illness, fever, cough, palpitations, or syncope. Medical history is significant for hypertension and breast adenocarcinoma treated with surgery and chemotherapy 6 years ago. The patient does not use tobacco or alcohol and has not traveled recently. Temperature is 37 C (98.6 F), blood pressure is 110/70 mm Hg, and pulse is 90/min. Physical examination shows changes consistent with prior right mastectomy. The right axillary lymph nodes are enlarged. The lungs are clear to auscultation. Heart sounds are distant with no murmur. There is no extremity edema. Bedside echocardiography shows a large pericardial effusion. Pericardiocentesis in this patient is most likely to reveal which of the following findings?
Pericardial effusion | |
Etiology |
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Clinical features |
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*Acute or large effusions. **With subacute & large effusions. CXR = chest x-ray; JVD = jugular venous distension; MI = myocardial infarction. | |
This patient with a history of right breast cancer, right axillary lymph node enlargement (ie, likely metastatic disease), and a large pericardial effusion (eg, distant heart sounds) most likely has malignant pericardial effusion.
Malignancy (eg, breast cancer) is a common cause of pericardial effusion and may be the initial manifestation of cancer recurrence. Pericardial involvement occurs by either direct tumor extension or metastatic spread through the blood or lymphatics; this often results in subacute accumulation (eg, over weeks) of pericardial fluid. Subacute (vs rapid) accumulation gives the pericardium time to progressively stretch, keeping intrapericardial pressure stable; during this period, patients often have only nonspecific symptoms (eg, dyspnea, chest discomfort). However, large volumes can eventually exceed the pericardium's stretch capacity, increase intrapericardial pressure, and compromise cardiac function.
When the cause of pericardial effusion is not clear, pericardiocentesis can be used to acquire fluid for laboratory analysis to help determine etiology. In malignant effusion, pericardial fluid is often hemorrhagic due to inflammation associated with metastatic invasion that causes bleeding from irritated capillaries. Cytologic analysis often reveals atypical malignant cells.
(Choice A) Some patients with pulmonary tuberculosis (TB) develop tuberculous pericarditis, which can be accompanied by pericardial effusion containing acid-fast bacilli. However, patients with tuberculous pericarditis typically have symptoms of extrapulmonary TB, including fever, night sweats, and weight loss. In addition, most patients are from, or have traveled to, areas where TB is endemic.
(Choices C and E) Bacteria (eg, Staphylococcus aureus [gram-positive cocci]) and fungi can cause purulent pericarditis, which may be accompanied by pericardial effusion containing gross pus (ie, purulent fluid) or microscopic purulence (ie, turbid fluid). However, most patients with purulent pericarditis are acutely ill (eg, fever, tachycardia) and have predisposing risk factors such as recent or ongoing infection, immunosuppression, or thoracic surgery.
(Choice D) Viral infection is a common cause of pericarditis, which can result in pericardial effusion. However, viral pericarditis is often preceded by viral respiratory or gastrointestinal symptoms. In this patient with evidence of metastatic breast cancer (eg, enlarged axillary lymph nodes) and no recent illness, malignant effusion is more likely.
Educational objective:
Malignancy is a common cause of pericardial effusion, which is often subacute due to slower accumulation of pericardial fluid with compensatory pericardial stretching. Pericardiocentesis can acquire fluid for cytologic analysis (eg, atypical cells) to help confirm the etiology.