Garrett Waagmeester 4/25/2014

 Total pleural fluid volume: mL/kg  Fluid produced by systemic vessels of the parietal pleura, primarily less dependent capillaries, based on: ◦ Permeability of the pleural vessels ◦ Hydrostatic and oncotic gradients  Fluid removed by pleural lymphatics in dependent portions of parietal pleura  Rate of production at homeostasis: 0.1 mL/kg/h Theodore et al, 2010; Suratt, 2003; Noppen et al, 2000

 Low in protein: <100 mg/dL  Slightly alkaline compared to serum: pH =  Hypocellular compared to serum ◦ WBC/μL  75% macrophages (IR 64-81%)*  23% lymphocytes (IR 16-31%)* * Median values; IR= interquartile range Suratt, 2003; Noppen et al., 2000

1. Increased pulmonary capillary pressure (CHF) 2. Increased pulmonary capillary permeability (PNA) 3. Decreased intrapleural pressure (Atelectasis) 4. Decreased plasma oncotic pressure (Hypoalbuminemia) 5. Increased pleural membrane permeability and obstructed lymphatic flow (pleural malignancy, infection) 6. Diaphragmatic defects (hepatic hydrothorax) 7. Thoracic Duct Rupture (chylothorax) Porcel and Light, 2006

Symptoms  Dyspnea ◦ Often disproportionate to hypoxemia  Cough  Pleuritic Chest Pain Physical Exam  Decreased breath sounds  Dullness to percussion  Decreased tactile fremitus  Egophony (E  A)  May find rales or pleuritic friction rub

 >50-75 mL of fluid on lateral radiograph to blunt costophrenic angle  > mL of fluid on P/A view to blunt lateral costophrenic angle  Clinically significant pleural effusion: >10mm fluid present on lateral decubitus radiograph (or U/S)

 Delayed thoracentesis in parapneumonic effusion associated with: ◦ Longer hospital stay ◦ Greater healthcare cost  Initial pleural fluid analysis: ◦ Protein ◦ LDH ◦ Cell count with differential ◦ Gram stain/culture ◦ Glucose ◦ Cytology ◦ pH Heffner et al, 1995; Light, 2002

Light, 2002

Transudative EffusionExudative Effusion Increased hydrostatic pressure Congestive Heart Failure Constrictive Pericarditis Pulmonary Embolism* Reduced oncotic pressure Nephrotic syndrome Malnutrition Transdiagphragmatic leakage Cirrhosis with ascites* Peritoneal dialysis Urinothorax* Decreased intrapleural pressure Atelectasis * Predominantly unilateral Lymphocytic predominance Tuberculous/Fungal pleuritis * Malignant disease (30-35%)* Sarcoidosis Neutrophilic predominance Parapneumonic effusion* Empyema* Rheumatoid disease Pulmonary infarction* Neutrophilic or lymphocytic Postcardiac injury (Dressler’s) syndrome Pulmonary embolism* Connective tissue disease Eosinophilic predominance Trauma Asbestos Drug-induced pleural disease RBC count >100,000 Malignancy* Trauma Pulmonary infarction* Other Chylothorax/Pseudochylothorax Suratt, 2003; Ansari and Idell, 1998; Light, 2006

 CT has higher sensitivity than CXR or MRI for: ◦ Pleural thickening and loculation ◦ Pleural vs. parenchymal disease  Empyema vs. abscess ◦ Pulmonary embolism  Helical CT ◦ Malignancy ◦ Mediastinal disease Porcell and Light, 2006; Davies et al, 2003; Qureshi and Gleeson, 2006; Sahn, 2007

 However, there are no trials demonstrating benefits of CT in terms of: ◦ Shorter time to diagnosis ◦ Decreased need for diagnostic procedures (e.g. thoracentesis) ◦ Shorter hospital stay/decreased cost  Management guidelines recommend CT scans for complicated cases after failed initial diagnostic workup Porcell and Light, 2006; Davies et al, 2003; Qureshi and Gleeson, 2006; Sahn, 2007

 Ultrasound ◦ Guided thoracentesis ◦ Identifies locultated effusion  Needle biopsy of pleura ◦ Tuberculous pleuritis and malignancy  Bronchoscopy ◦ Bronchial invasion by malignancy or infiltrate  Thoracoscopy ◦ Allows for pathologic analysis ◦ Option for pleurodesis  Open biopsy Davies et al, 2003; Light, 2006; Sahn, 2007

 Pleural fluid is produced and removed by parietal pleura ◦ Multiple mechanisms to disrupt homeostasis  Thoracentesis essential to diagnosis ◦ Light’s criteria: sensitive and specific for identifying exudative effusions  CT scan can be helpful for complicated cases

1. Theodore PR, Jablons D. Chapter 18. Thoracic Wall, Pleura, Mediastinum, & Lung. In: Doherty GM. eds. CURRENT Diagnosis & Treatment: Surgery, 13e.New York, NY: McGraw-Hill; Accessed April 18, Suratt BT. Chapter 22. Pleural Effusions, Excluding Hemothorax. In:Hanley ME, Welsh CH. eds. CURRENT Diagnosis & Treatment in Pulmonary Medicine. New York, NY: McGraw-Hill; Accessed April 18, Noppen M, De Waele M, Li R, Gucht KV, D’Haese J, Gerlo E. Volume and Cellular Content of Normal Pleural Fluid in Humans Examined by Pleural Lavage. Am J Respir Crit Care Med 2000; 162: Porcel JM, Light RW. Diagnostic Approach to Pleural Effusion in Adults. Am Fam Physician 2006; 73: Heffner JE, McDonald J, Barbieri C, Klein J. Management of Parapneumonic Effusion: an analysis of physician practice patterns. Arch Surg 1995; 130: Light RW. Pleural Effusion. NEJM 2002; 346: Ansari T, Idell S. Management of Undiagnosed Persistent Pleural Effusion. Clin Chest Med 1998; 19(2): Light RW. The Undiagnosed Pleural Effusion. Clin Chest Med 2006; 27: Qureshi NR, Gleeson FV. Imaging of Pleural Disease. Clin Chest Med 2006; 27: Davies CWH, Gleeson FV, Davies RJO. BTS Guidelines for the management of pleural infection. Thorax 2003; 58(ii): Sahn SA. Diagnosis and Management of Parapneumonic Effusions and Empyema. Clin Infect Disease 2007; 45: Light RW. Pleural Effusions. Med Clin N Am 2011; 95: