Objective: To describe the characteristics of patients with pleural effusion (PE) and the causes of PE in a prospective, consecutive series of patients.
Setting: A tertiary care hospital associated with the Universidad Complutense de Madrid (Spain).
Patients: One thousand consecutive patients with PE for whom clinical signs indicated the need for diagnostic thoracocentesis were studied prospectively in our service from December 1991 to July 2000.
Results: The most common cause of PE was neoplasm (n = 364 patients). The most common place of origin of the tumor was the lung (n = 125), followed by the pleura (mesothelioma, n = 48). The most common histologic type was adenocarcinoma (n = 128). Tuberculosis was the second most common cause of PE (n = 155). PE was transudate in 118 patients, mainly secondary to heart failure. Among the 42 patients who were positive for human immunodeficiency virus (HIV), the most common cause of PE was tuberculosis. Tuberculosis was also the most likely cause of PE in patients under 40 years of age.
Conclusions: The most common causes of PE were neoplasm and tuberculosis. Tuberculosis was the most common cause in patients under 40 years of age and in those infected by HIV.