Tuberculous pleural effusion.

Tuberculous pleural effusion (TBPE) is the most common form of extrapulmonary tuberculosis (TB) in Spain, and is one of the most frequent causes of pleural effusion. Although the incidence has steadily declined (4.8 cases/100,000population in 2009), the percentage of TBPE remains steady with respect to the total number of TB cases (14.3%-19.3%). Almost two thirds are men, more than 60% are aged between 15-44years, and it is more common in patients with human immunodeficiency virus. The pathogenesis is usually a delayed hypersensitivity reaction. Symptoms vary depending on the population (more acute in young people and more prolonged in the elderly). The effusion is almost invariably a unilateral exudate (according to Light's criteria), more often on the right side, and the tuberculin test is negative in one third of cases. There are limitations in making a definitive diagnosis, so various pleural fluid biomarkers have been used for this. The combination of adenosine deaminase and lymphocyte percentage may be useful in this respect. Treatment is the same as for any TB. The addition of corticosteroids is not advisable, and chest drainage could help to improve symptoms more rapidly in large effusions.