Pleural effusions.

Pleural effusions develop following changes in capillary permeability, capillary hydrostatic pressure, plasma colloid osmotic pressure, or lymphatic drainage. Generalized fluid retention or a transudate suggests a systemic cause while an exudate suggests a local cause. The diagnosis can usually be established by clinical assessment, chest radiography, analysis of pleural fluid, pleural biopsy, and appropriate special investigations. When no cause can be found, particular care should be taken to exclude secondary carcinoma, tuberculosis, pulmonary infarction, and mesothelioma; the patient should be followed-up. Symptomatic malignant effusions may be managed initially by basal intercostal tube drainage alone. For recurrences, local instillation first of tetracycline and then of mustine may be tried. Pleurectomy should be considered if the prognosis is otherwise good.