Pleural effusion is accumulation of serous fluid in pleural space resulting from excess fluid production or decreased absorption or both. The pleural space is bordered by the parietal and visceral pleurae. The pleural space plays an important role in respiration by coupling the movement of the chest wall with that of the lungs. The normal pleural space contains approximately 10 mL of fluid, representing the balance between (a) hydrostatic and oncotic forces in the visceral and parietal pleural vessels and (b) extensive lymphatic drainage. Pleural effusions result from disruption of this balance.
Pleural effusion is of two types (a) Transduative pleural effusion
(b) Exudative pleural effusion
Transudates result from an imbalance of oncotic and hydrostatic pressures, whereas exudates are the result of inflammatory processes of the pleura and/or decreased lymphatic drainage. Transduative effusion occurs in extra pulmonary conditions, examples congestive heart failure, cirrhosis or renal failure.
Exudative effusion occurs in pulmonary conditions examples, pneumonia, tuberculosis, pulmonary and embolism etc. Clinical features involve chest pain, dyspnea, and cough. Other symptoms in association with pleural effusions may suggest the underlying disease process. Increasing lower extremity edema, orthopnea, and paroxysmal nocturnal dyspnea may all occur with congestive heart failure. Night sweats, fever, hemoptysis, and weight loss suggest TB.
Treatment approach – (a) diagnosing underlying pathology (b) symptomatic relief.
Thoracentesis, pleurodesis can be performed. Medications cause only a small proportion of all pleural effusions and are associated with exudative pleural effusions. Patient positioning and chest splinting can provide pain relief during deep breathing and coughing.