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  • • Presence of fluid within pleural space

    • Etiology includes:

    • -Increased pulmonary hydrostatic pressure

      -Decreased intravascular oncotic pressure

      -Increased capillary permeability

      -Decreased intrapleural pressure (atelectasis)

      -Decreased lymphatic drainage (carcinomatosis)

      -Rupture of vascular or lymphatic structure (trauma)

    • When nature of fluid of known, more specific terms may be used:

    • -Pyothorax: Pus in pleural cavity (empyema)

      -Hemothorax: Blood in thorax

      -Chylothorax: Chyle in thorax

      -Hydrothorax: Collection of serous fluid (transudative or exudative)

    • Etiology for hydrothorax:

    • -Tuberculosis: History of exposure, can be sanguineous; > 1000 lymphocytes, positive for acid-fast bacilli, positive tuberculin skin test, positive pleural biopsy, glucose < 60 mg/dL

      -Cancer: 67% bloody, cytology positive in 50%, glucose rarely < 60 mg/dL

      -Congestive heart failure (CHF): Presence of CHF, serous, < 10,000 RBCs, right-sided in up to 70%, may be bilateral; interlobal fissure fluid collection called "pseudotumors"

      -Pneumonia: Respiratory infection, serous, neutrophils predominate in fluid, culture and stain positive for organisms, infiltrate on chest film

      -Rheumatoid arthritis: Joint involvement, turbid or yellow-green color, lymphocytes predominate, glucose < 20 mg/dL, rapid clotting time, eosinophils present

      -Pulmonary embolism: Risk for embolism, often sanguineous

      -Other causes: Nephrotic syndrome, rupture of hydronephrosis into pleural space (elevated creatinine in fluid), pancreatitis (left-sided, elevated amylase), cirrhosis (5% of patients with ascites)

    • Etiology for chylothorax:

    • -Most often due to surgical procedures

      -Other causes include trauma, malignancy, central line placement, thoracic aortic aneurysms, filariasis

      -Blunt trauma: Thoracic duct shearing at diaphragm




  • • > 25% of pleural effusions are secondary to malignancy

    • Malignant effusions occur in patients with lung cancer (35%), breast cancer (23%), lymphoma (10%)

    • 10% of malignant effusions secondary to primary pleural tumors (mesothelioma most common)


Symptoms and Signs


  • • Decreased respiratory excursions

    • Diminished breath sounds

    • Dullness to percussion

    • Decreased vocal/tactile fremitus

    • Pleural friction rub

    • Long-standing disease: Contraction of hemithorax


Laboratory Findings


  • • Fluid: Acid-fast bacilli: TB

    • Send fluid for total protein, lactic dehydrogenase (LDH), glucose, specific gravity, amylase, creatinine, pH, cytology


Imaging Findings


  • Chest film: Blunting of costophrenic angle = 250-500 mL of fluid; entire hemithorax effusion: > 2 L


  • • Criteria for diagnosing transudates by thoracentesis fluid:

    • -LDH < 200 U/dL (fluid:serum ratio < 0.6

      -Total protein < 3 g/dL (fluid:serum < 0.5)

      -Specific gravity < 1.016

    • Malignant effusions:

    • -Serous, serosanguineous, bloody

      -Cytology positive in 50-75% with repeated thoracentesis

    • Closed pleural biopsy positive thoracentesis cytology: 80% diagnostic yield

    • Thoracoscopy with pleural biopsy: 97% diagnostic yield


Rule Out


  • • TB

    • Cancer

    • CHF

    • Pneumonia

    • Rheumatoid arthritis/collagen disease

    • Pulmonary embolism


  • • Chest x-ray

    • Thoracentesis


  • • Malignant effusions

    • -Goal is palliation plus lung reexpansion

      -Chest tube (drains 1 L initially, allow 200 mL drainage every hour until completely drained)

      -Chemical pleurodesis (talc, doxycycline)

      -Bilateral pleurodesis contraindication due to risk of acute respiratory distress syndrome

    • CHF

    • -Treat underlying failure


    • Chylothorax

    • -Closed chest tube drainage

      -Low fat diet

      -Chyle typically causes pleurodesis; however, drainage > 7 days may need intervention (significant protein losses)

      -Video-assisted thoracoscopic technique: Ligation of thoracic duct at diaphragm between aorta and azygous vein

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