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Accuracy of the physical examination in evaluating pleural effusion

Cleveland Clinic Journal of Medicine. 2008 April;75(4):297-303
April 1, 2008|Cleveland Clinic Journal of Medicine
Enrique Diaz-Guzman, MD;Marie M. Budev, DO, MPH
Author and Disclosure Information

Enrique Diaz-Guzman, MD
Department of Pulmonary, Allergy, and Critical Care Medicine, Pulmonary Institute, Cleveland Clinic

Marie M. Budev, DO, MPH
Department of Pulmonary, Allergy, and Critical Care Medicine, Pulmonary Institute, Cleveland Clinic

Address: Marie M. Budev, DO, MPH, Department of Pulmonary and Critical Care Medicine, A90, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195; e-mail budevm@ccf.org

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.

KEY POINTS

  • 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.

Bigger effusions are easier to detect

The physical findings are related to the volume of fluid in the pleural effusion and its effects on the chest wall, diaphragm, and lungs. Physical findings are generally normal if less than 300 mL of fluid is present, whereas large effusions (> 1,500 mL) can be associated with significant asymmetry of chest expansion and bulging of intercostal spaces.

Table 3 shows some of the common physical findings, depending on the amount of pleural fluid present.

Inspection

Although inspection of the chest is not very helpful in detecting a pleural effusion, it can provide other relevant information such as the respiratory rate and the breathing position adopted by the patient (patients with a large pleural effusion may have orthopnea); it can also reveal abnormalities in the shape of the thorax such as the increased anteroposterior diameter (“barrel shape”) seen in patients with chronic obstructive pulmonary disease.18

In addition, by inspection we can assess the expansion of the thorax. The utility of inspecting chest expansion to detect lung restriction was first noted by Laennec19 in 1821. A simple method of evaluating chest expansion is to place a measuring tape around the chest at the level of the nipples to compare the circumference at end-inspiration and at end-expiration.20 In the absence of emphysema, the difference should be at least 2 inches. An expansion of 1.5 inches or less is considered abnormal.21 More relevant to pleural effusion than the amount of overall chest expansion is whether the expansion is symmetrical, which we can assess by palpation.

Palpation

Signs of pleural effusion that can be detected by palpation include asymmetric chest expansion and asymmetric tactile fremitus.

Figure 1. Palpation to detect asymmetry of chest expansion, a sign of pleural effusion.
Chest expansion can be evaluated by placing your hands on the patient’s back with your thumbs pointed towards the spine and asking the patient to breathe (Figure 1). In a recent study by Kalantri et al10 in 278 patients (of whom 57% had pleural effusions), asymmetric chest expansion had a sensitivity of 74% and a specificity of 91%. Furthermore, when the pretest probability of disease based on other clinical findings was applied, symmetrical chest expansion was associated with a very low probability (8%) of pleural effusion.

Figure 2. Tactile fremitus—the examiner asks the patient to say specific words repeatedly (eg, “ninety-nine”).
Tactile fremitus is defined as the vibration felt by the clinician’s hand resting on the chest wall of a patient (Figure 2).22 To elicit the sign, the clinician asks the patient to say specific words repeatedly (eg, “ninety-nine”). Asymmetry of tactile fremitus can be due to air, fluid, or tumors, and thus this sign is not specific for pleural effusion. Little information is available about its accuracy, although in the study by Kalantri et al,10 its sensitivity was 82%, its specificity was 86%, and its positive predictive value was low at 59%.

Other signs. Palpation of the chest can also help in detecting underlying disease of the thorax sometimes associated with pleurisy or pleural effusions. Chest wall tumors or skin abscesses may be related to underlying empyema, localized tenderness may be associated with rib fractures or costochondritis, and crepitus may be due to subcutaneous emphysema.

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