Management of pleural effusions.

This review summarizes current strategies in the treatment of patients with pleural effusion. To determine whether a patient has a transudative or exudative pleural effusion, Light's criteria should be applied to measure the concentrations of protein and lactate dehydrogenase (LDH) in the pleural fluid and serum. If the effusion is transudative, therapy should be directed toward the underlying congestive heart failure, cirrhosis, or nephrosis. Consideration should be given to pleurodesis with a sclerosant if patients with recurrent transudative effusion have severe dyspnea due to their effusion. If the effusion is exudative, attempts should be made to define the etiology. The diagnosis of pleural malignancy is most easily established via pleural fluid cytology. If this is negative and the patient is suspected of having pleural malignancy, thoracoscopy is indicated. The concentrations of adenosine deaminase and gamma-interferon in pleural fluid are useful in the diagnosis of pleural tuberculosis. Patients with pneumonia and pleural effusion should undergo therapeutic thoracentesis; the pleural fluid should be Gram-stained and cultured, and the differential cell count, glucose and LDH concentration, and pH should be determined. Indicators of a poor prognosis include the presence of frank pus, a positive Gram-stain, a pleural glucose concentration of less than 2.2 mmol/L, a pH less than 7.00, the presence of pleural loculations, and an LDH concentration greater than three times the upper limit of normal in serum. If the pleural fluid cannot be completely evacuated because of loculations, intrapleural thrombolytic therapy should be considered. If thrombolytics are ineffective, thoracoscopy or thoracotomy with decortication should be performed. Dyspneic patients with malignant pleural effusions whose dyspnea is relieved with therapeutic thoracentesis should be considered for pleurodesis using a tetracycline derivative. Talc is not recommended because it induces acute respiratory distress syndrome in about 5% of patients, with an overall mortality of 1%.