TY - JOUR T1 - The role of Epstein-Barr virus in pleural effusions of unknown aetiology: an interesting clinical perspective JF - European Respiratory Journal JO - Eur Respir J SP - 566 LP - 568 DO - 10.1183/09031936.05.00082105 VL - 26 IS - 4 AU - E. Martró AU - V. Ausina Y1 - 2005/10/01 UR - http://erj.ersjournals.com/content/26/4/566.abstract N2 - Pleural effusion is a relatively common clinical condition that requires a differential diagnosis as it may represent the primary manifestation of certain diseases; however, it is commonly observed as a secondary manifestation or complication of other diseases. Primary causes include cardiac failure, infectious aetiology (75% bacterial and 25% viral), and malignancy (mostly lung and breast cancer), while the other diseases comprise pulmonary embolism, liver cirrhosis, subphrenic abscess or pancreatitis 1. In addition, symptoms associated with pleural effusions, such as cough, dyspnoea and chest pain, are nonspecific. Therefore, the history of the patient, physical findings and laboratory tests are necessary for the clinician to narrow down the differential diagnosis 2. The cause of pleural effusion may be determined in most cases, depending on clinical presentation, imaging techniques and pleural fluid analysis. Pleural fluid analysis is the most useful test and, together with clinical information, usually allows the diagnosis of pleural effusion in ∼75% of patients 3. A definite diagnosis can generally be obtained in ∼25% of cases, after finding malignant cells or microorganisms. In ∼50% of cases, only a presumptive diagnosis can be obtained based on clinical impression. After excluding an infection as the cause of the pleural effusion, clinical orientation upon pleural fluid analysis is possible in a greater percentage of patients. In cases where a diagnosis cannot be obtained, observation of the patient, repeated pleural fluid analysis or more invasive procedures may be indicated. Even after invasive procedures, such as thoracoscopy, are used, the cause of the pleural effusion cannot be established in up to 15% of patients 4. Thoracocentesis is indicated in all clinically significant pleural effusions of unknown origin and in effusions that do not respond to treatment. Pleural fluid biochemical analysis allows the classification into transudates (caused by imbalances between the hydrostatic … ER -