Snapshot A 55-year-old male with congestive heart failure, coronary artery disease, and hypertension presents to your urgent care with shortness of breath. He is on vacation and lost his medications during his travel. He reports that his shortness of breath has been getting worse over the past few days, especially when he is walking. His exam is notable for decreased lung sounds bilaterally with overlying dullness to percussion and bilateral 1+ pitting edema to the knees. A chest radiograph was performed, which showed blunting of the costophrenic angles. Introduction Clinical definition pathologic accumulation of fluid in the pleural space (5 - 10 cc physiologically) Epidemiology incidence the most common cause in the United States congestive heart failure, pneumonia, and malignancy the most common cause in the world tuberculosis Etiology any abnormal balance between fluid entering and/or exiting pleural space Pathogenesis characteristics of the fluid suggest the pathogenesis transudative ↑ hydrostatic pressure or ↓ capillary oncotic pressure exudative ↑ capillary permeability Prognosis depends on etiology and baseline pulmonary function Presentation Symptoms asymptomatic dyspnea and/or dyspnea on exertion cough Physical examination ↓ breath sounds ↓ tactile fremitus versus consolidation, which ↑ breath sounds Special presentation hepatic hydrothorax intra-abdominal fluid enters via diaphragmatic defects Imaging Chest radiography upright show blunting of the costophrenic angles lateral decubitus shows layering if free flowing Studies Thoracentesis diagnostic gold standard indicated for new effusions Fluid studies Gram stain and culture cell count with differential cytology Light criteria Light Criteria for Pleural Fluid Analysis Transudative Exudative Fluid LDH ≤ 2/3 upper limit of normal serum > 2/3 upper limit of normal serum Fluid LDH/Serum LDH ≤ 0.6 > 0.6 Fluid total protein/serum total protein ≤ 0.5 > 0.5 Diagnosis Must meet all criteria to diagnose a transudate Meet any single criterion to diagnose exudate Differential Diagnosis Pyothorax Hemothorax Chylothorax Treatment Management approach if high suspicion of congestive heart failure, diurese if new effusion, perform diagnostic and therapeutic thoracentesis concurrent treatment of the underlying disease Interventional therapeutic thoracentesis thoracostomy or thoracotomy indication loculated effusions pleurodesis and decortication indication indwelling catheter for recurrent effusion Complications Empyema Loculation Pneumothorax from thoracentesis