40 Pleural Effusions and Pneumothorax
Pleural effusions and pneumothoraces occur as a result of structural and mechanical abnormalities of the pleural space. Abnormalities of the pleural space are an important cause of morbidity and mortality in infants and children worldwide, and the number of children who develop clinically significant pleural effusions is increasing. Pleural effusions are the result of excessive fluid accumulation in the pleural space, and pneumothoraces occur as a result of the accumulation of air within the pleural space. To better understand the pathophysiology of pleural effusions and pneumothoraces, it is essential to understand the anatomy of the pleural space. The pleural space is a potential anatomic space, approximately 10 to 20 µm wide, located between the visceral and parietal pleurae. The visceral pleura lines the surface of the lung parenchyma, including the interlobar fissures, and the parietal pleura lines the inner surface of the chest wall, mediastinum, and diaphragm (Figure 40-1). The pleural space contains a small amount of fluid (0.3 mL/kg body weight) that is in equilibrium between the amount of fluid formed (filtered) and the amount removed (absorbed).
Pleural Effusions
Evaluation and Management
Children with the clinical history and findings suggestive of a pleural effusion should be evaluated with an upright chest radiograph and a lateral decubitus view (Figure 40-2). Performing radiographic examinations with the child in multiple positions helps to demonstrate a shift in the effusion with position changes. These radiographic images can help in making the diagnosis of pleural effusion and in determining the need for thoracocentesis or chest tube placement.