From the Guidelines
Yes, it is common for a pulmonary embolism (PE) to cause a pleural effusion, with approximately 30-50% of patients with a PE developing a pleural effusion, though these effusions are typically small to moderate in size. The mechanism involves inflammation and increased vascular permeability in the lungs following the embolism, which leads to fluid accumulation in the pleural space. These effusions are usually exudative and often bloody (hemorrhagic) due to capillary damage. PE-associated effusions most commonly occur on the same side as the embolism and may develop within 24-72 hours after the PE occurs.
When evaluating a patient with unexplained pleural effusion, especially if it's unilateral and associated with shortness of breath, chest pain, or risk factors for thromboembolism, clinicians should consider PE in the differential diagnosis 1. The presence of a pleural effusion in a patient with PE doesn't necessarily change the standard treatment approach, which focuses on anticoagulation therapy to prevent further clot formation and allow the body to dissolve the existing clot. Key considerations in managing PE include the risk of recurrent PE, especially during the first 4–6 weeks, and the importance of timely diagnosis and anticoagulant therapy to reduce mortality from approximately 25% to 30% to less than 8% 1.
Some key points to consider in the management of PE and associated pleural effusions include:
- The classification of PE into massive and non-massive categories, with the latter potentially being further subdivided into submassive based on echocardiographic signs of right ventricular hypokinesis 1.
- The importance of early diagnosis and treatment to prevent potentially fatal early recurrences and to improve long-term outcomes 1.
- The need for a validated diagnostic strategy to justify initial treatment and long-term anticoagulation in each patient 1.
Overall, the development of a pleural effusion in the context of a PE is a significant clinical finding that requires prompt evaluation and management to optimize patient outcomes.
From the Research
Incidence of Pleural Effusion in Pulmonary Embolism
- Pulmonary embolism (PE) is a common cause of pleural effusion, with an estimated 300,000 to 500,000 patients developing a pleural effusion secondary to PE each year in the United States 2.
- The incidence of pleural effusion in patients with PE is approximately 48% 3.
- Pleural effusions due to PE are usually small, occupying less than one-third of the hemithorax in 90% of cases 2.
Characteristics of Pleural Effusion in Pulmonary Embolism
- The pleural fluid in PE is almost always an exudate, frequently hemorrhagic, and with a marked mesothelial hyperplasia 4.
- The presence of bloody pleural fluid is not a contraindication for the administration of anticoagulant therapy 4.
- Dyspnea is frequently out of proportion to the size of the pleural effusion 5.
Diagnosis and Treatment of Pleural Effusion in Pulmonary Embolism
- The diagnosis of PE should be considered in patients presenting with acute chest pain, shortness of breath, or syncope, and can be evaluated using a structured score or clinical gestalt, D-dimer testing, and chest imaging 6.
- The presence of a pleural effusion does not alter the standard treatment for PE, which typically consists of anticoagulation therapy 4, 2.
- Direct oral anticoagulants such as apixaban, edoxaban, rivaroxaban, or dabigatran are noninferior to heparin and warfarin for treating PE and have a lower rate of bleeding 6.