What are the signs and symptoms of a pleural effusion (fluid on the lungs)?

Updated: Dec 28, 2018
  • Author: Kamran Boka, MD, MS; Chief Editor: Guy W Soo Hoo, MD, MPH  more...
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The clinical manifestations of pleural effusion are variable and often are related to the underlying disease process. The most commonly associated symptoms are progressive dyspnea, cough, and pleuritic chest pain.


Dyspnea is the most common symptom associated with pleural effusion and is related more to distortion of the diaphragm and chest wall during respiration than to hypoxemia. In many patients, drainage of pleural fluid alleviates dyspnea despite limited alterations in gas exchange. Drainage of pleural fluid may also allow the underlying disease to be more easily recognized on repeat chest radiographs. Note that dyspnea may be caused by the condition producing the pleural effusion, such as underlying intrinsic lung or heart disease or obstructing endobronchial lesions rather than by the effusion itself.


Cough in patients with pleural effusion is often mild and nonproductive. More severe cough or the production of purulent or bloody sputum suggests an underlying pneumonia or endobronchial lesion.

Chest pain

The presence of chest pain, which results from pleural irritation, raises the likelihood of an exudative etiology, such as pleural infection, mesothelioma, or pulmonary infarction. [19]

Pain may be mild or severe. It is typically described as sharp or stabbing and is exacerbated with deep inspiration. Pain may be localized to the chest wall or referred to the ipsilateral shoulder or upper abdomen because of diaphragmatic irritation. Pain may diminish in intensity as the pleural effusion increases in size and the inflamed pleural surfaces are no longer in contact with each other.

Extrapulmonary symptoms

Other symptoms in association with pleural effusions may suggest the underlying disease process. Increasing lower extremity edema, orthopnea, and paroxysmal nocturnal dyspnea may all occur with congestive heart failure.

Night sweats, fever, hemoptysis, and weight loss should suggest TB. Hemoptysis also raises the possibility of malignancy, other endotracheal or endobronchial pathology, or pulmonary infarction. An acute febrile episode, purulent sputum production, and pleuritic chest pain may occur in patients with an effusion associated with pneumonia.

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