The management of pleural space infections

Pleural infection is responsible for significant morbidity and mortality worldwide, and its clinical management is challenging. The diagnosis of empyema and tuberculous pleurisy may be difficult, and these conditions may be confused with other causes of exudative pleural effusions. Complicated parapneumonic effusion or empyema may present with 'atypical' clinical features; delays in diagnosis are common and may contribute to the high mortality of these infections. Pleural aspiration is the key diagnostic step; pleural fluid that is purulent or that has a pH < 7.2, or organisms on Gram stain or culture, is an indication for formal intercostal drainage. In order to achieve a definitive diagnosis of tuberculous pleurisy, Mycobacterium tuberculosis must be isolated in the culture of pleural fluid, pleural tissue or sputum; demonstration of granulomas in pleural tissue is also suggestive of tuberculosis. The use of pleural fluid biochemical markers, such as adenosine deaminase, in the diagnosis of tuberculous pleurisy varies among clinicians; the diagnostic value of such markers is affected by the background prevalence of tuberculosis and the likelihood of an alternative diagnosis. Uncertainties also remain regarding the treatment of pleural infection. Treatment of complicated parapneumonic effusion and empyema involves prolonged courses of antibiotics and attention to the patient's nutritional state. The role of intrapleural fibrinolytics and the optimal timing of surgical intervention are unknown. The lack of clear predictors of clinical outcome in empyema contributes to the difficulty in treating this condition. The pharmacological treatment of tuberculous pleurisy is the same as for pulmonary tuberculosis; the precise role of steroids in the treatment of tuberculous pleurisy remains uncertain.