Accuracy of the physical examination in evaluating pleural effusion

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ABSTRACTA careful physical examination is a valuable and noninvasive means of assessing pleural effusion and should be routinely performed in every patient in whom this condition is suspected. Although physical examination is less accurate than ultrasonography or computed tomography in detecting a pleural effusion, the sensitivity and specificity of the different physical signs of pleural effusion may be comparable to those of conventional chest radiography.


  • The potential causes of pleural effusion are many and include congestive heart failure, pneumonia, cancer, and pulmonary embolism.
  • Cardinal symptoms of pleural effusion are cough, chest pain, and dyspnea, but these are not very sensitive or specific.
  • Common signs of pleural effusion are asymmetric chest expansion, asymmetric tactile fremitus, dullness to percussion, absent or diminished breath sounds, and rubs. The larger the effusion, the more sensitive these signs are.
  • Some have advocated auscultatory percussion (tapping on the manubrium while listening on the patient’s back) as being more sensitive than conventional percussion for detecting the dullness to percussion of pleural effusion.



In detecting and evaluating pleural effusion, technology has not replaced clinical skills. Yet, despite centuries of lore, data are limited on the role of the physical examination and on its accuracy compared with other noninvasive tests such as conventional chest radiography or ultrasonography.

The following is an overview of the value of the clinical history and physical examination in detecting pleural effusion and a brief review of the available information regarding its accuracy compared with other diagnostic methods.


The pleurae consist of two membranes that protect the lungs, allow them to move, contribute to their shape, and prevent the alveoli at the pleural surface from becoming overdistended. Between the visceral pleura (covering the lung) and the parietal pleura (covering the diaphragm and the chest wall) is the pleural space.

In healthy adults, the pleural space contains an estimated 5 to 10 mL of pleural fluid (0.1 mg/kg body weight). 1 Pleural effusion is an accumulation of an abnormal amount of fluid in the pleural space.

Although the potential causes are many, the most common are congestive heart failure, pneumonia (40% of patients hospitalized with pneumonia have pleural effusion), 2,3 cancer, and pulmonary embolism. 4

Because many diseases affecting different organs can cause a pleural effusion, we cannot overemphasize the importance of a thorough history and physical examination to uncover clues that will help identify its cause and narrow the diagnostic workup. For example, significant weight loss and cachexia could be due to cancer, and joint, skin, or eye symptoms could be due to a connective tissue disorder.

A thorough review of the patient’s medications is mandatory, since several medications (eg, amiodarone [Cordarone], methotrexate [Rheumatrex, Trexall], and nitrofurantoin [Macrobid]) can be associated with exudative effusions. In addition, the patient’s occupational history must be ascertained, since exposure to asbestos can raise the suspicion of a malignant disease of the pleura such as mesothelioma.


The symptoms of pleural effusion are neither sensitive nor specific, and many patients have manifestations of the underlying process but not of the effusion itself. The most common symptoms directly related to effusion are cough, dyspnea, and pleuritic chest pain. 5

Cough. Many patients with a pleural effusion have a dry, nonproductive cough, a consequence of inflammation of the pleurae or compression of the bronchial walls. Although this symptom is rarely helpful in diagnosing a pleural effusion, if accompanied by purulent sputum it suggests pneumonia, and if complicated by hemoptysis it suggests cancer or pulmonary embolism.

Dyspnea is a consequence of a combination of a restrictive lung defect, a ventilation-perfusion mismatch, and a decrease in cardiac output. Although large pleural effusions reduce lung volume and are generally associated with dyspnea, the symptoms may be out of proportion to the size of the effusion, and patients with small to moderate effusions may also have shortness of breath if their baseline lung function is poor. 2

Chest pain accompanying a pleural effusion suggests inflammation of the parietal pleura, 6 but could be due to cancer in the chest wall and ribs—or to a benign disease of the thoracic wall such as rib fracture or costo-chondritis.


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