Disorders of the Pleural Space

Edward M. Omron MD, MPH, FCCP

Pulmonary Medicine

Alta Bates Summit

10-19-2010

Which of the following pleural fluid measurements is most compatible with an exudative pleural effusion?

• Cholesterol is 35 mg/dL• LDH is 0.40 times the upper limit of normal • LDH pleural fluid to serum ratio is 0.52• Total protein is 3.4 g/dL

• 67 yo male presents:– Dyspnea 8 weeks, fever, cough, pleuritic chest pain– 3 vessel CABG 3 months ago with internal mammary

artery graft– Decreased breath sounds on left– WBC 11,000, ESR = 80 mm/h, – CXR: left effusion with atelectasis– Thoracentesis: 800 mL straw colored fluid removed

• 70% lymphocytes, 20% PMNS, and 40,000 RBC/mm3• Protein 4.2 g/dL, glucose 90 mg/dL, LDH 300 U/L• pH = 7.3

What is the next step in this patients management?

• Consult CT surgery• Begin antiinflammatory agent• Begin therapeutic low molecular weght heparin

while awaiting CT angiogram• Begin piperacillin/tazobactam with Vancomycin

• Post-cardiac injury syndrome or Dressler Syndrome– Post CABG effusions (common)– Exaggerated immune response to cardiac

antigens– Pleuritic chest pain, fever, elevated ESR,

leukocytosis, antimyocardial antibodies– Initially neutrophil predominat <30 days then

lymphocyte predominant >30 days– Often requires NSAIDS or steroids for

resolution– 1 -12 months after surgery, 3 weeks is median

Normal Pleural Physiology

• Functions of pleural space– Couples the lungs to the chest wall– Lubricant between the chest wall and lungs– Obliteration of space compatible with life

• Composition– 2 separate semipermeable membranes– Visceral and Parietal layers– Both linings subject to disease and disorders

• Visceral Pleura– Envelops entire surface of both lungs– The two pleural cavities are separate– Mesothelial cells– Artery Supply: bronchial arteries– Lymphatics drain the pulmonary

parenchyma– No nerve fibers– The vein drain is pulmonary vein

• Parietal Pleura– Covers the inner surface of chest wall– Blood supply intercostal arteries– Lymphatics drain the pleural space– Pain fibers are present from intercostal

nerves– Mesothelial cells are immunoreactive– 5 to 15 mL fluid present in space– Normally high fluid flux 1 Liter /day– Vein drain is the superior vena cava

Normal Composition Pleural Fluid

• Volume 0.2 mL/kg• Cells/ mm3 1000 – 5000

– Mesothelial cells 60%– Monocytes 30%– Lymphocytes 5% – PMN’s 5%

• Protein 1-2 g/dL• LDH <50% plasma level• Glucose plasma level• pH ≥ plasma level

Visceral and Parietal Pleura

Pleural Histology

The visceral pleura is made from simple squamous epithelium (mesothelium)

Pleural Effusion

• Fluid in pleural space > 20 mL• Two mechanisms

– Excessive formation– Fluid resorption is disturbed

• Etiology– 40% cardiac causes– 60% other

• Pneumonia (48%)• Malignancy(24%)• Pulmonary embolism (18%)• Cirrhosis (6%)

Initial Evaluation of Pleural Effusion

• History and physical exam are critical– Dyspnea, cough and pleuritic chest pain are

common– Fever: pneumonia, empyema, tuberculosis (Tb)– Hemoptysis: lung cancer, PE, or Tb– Weight Loss: Malignancy, Tb, or lung abscess– Chest Exam

• Dullness to percussion• Decreased breath sounds

• Signs– Orthopnea, jvd, or peripheral edema (CHF)– Unilateral extremity swelling (PE)– Ascites (hepatic hydrothorax or Meig’s)

• History– Chest trauma (hemothorax)– Abdominal surgery (post-op effusion)– Post CABG surgery (Dressler’s syndrome)– Alcoholism (pancreatic effusion)

Imaging Pleural Effusion

• PA and Lateral CXR• Decubiti for layering• CT chest for complex spaces• US for direct visualization

Right-sided Pleural Effusion

Right Side Down Ducubitus

Bilateral Pleural Effusions CT Chest

Ultrasound Pleural Effusion

• Should thoracentesis be performed?

• If thoracentesis is done– Is the fluid a transudate or exudate?

• If the fluid is an exudate– What is the etiology?

Pleural Effusion Confirmed

Should Thoracentesis Be Performed?

• Most patients should be tapped– Newly recognized effusion

• Two exceptions– Small Effusions ( < 1 cm on decubitus, US

required)– Congestive Heart Failure

• Thoracentesis only if bilateral effusions not equal• Fever• Pleuritic chest pain• Impending respiratory faillure

Is the Fluid a Transudate or Exudate?

• Transudative Effusions– Mechanical– No capillary leak or cytokine activation– Excessive formation or impaired absorption– Limits the differential with no additional workup

• CHF, Cirrhosis, or Nephrotic Syndrome

– If Exudative, more investigation required– Method: LIGHT’s Criteria

Light’s Criteria (Exudate)

• Pleural fluid total protein/ serum protein >0.5– Pleural total protein > 2.9 g/dL

• Pleural fluid LDH/serum LDH > 0.6– Pleural fluid LDH > 0.45 upper limit normal

• Serum albumin minus pleural albumin < 1.2• Pleural fluid total cholesterol > 45 mg/dL

Chest 2003; 121: 1916-1920

Transudative Effusions

• Congestive Heart Failure• Nephrotic syndrome• Cirrhosis• Meig’s Syndrome• Hydronephrosis• Peritoneal Dialysis

Exudative Effusions

• Parapneumonic• Malignancy• Pulmonary Embolism• Tuberculosis• Traumatic• Collagen Vascular (SLE, RA)• Drug induced, Uremia, Dressler’s …

Other Useful Criteria

• Brain Natriuretric Peptide <1000 pg/mL– > 1000 in CHF

• Glucose < 60 mg/dL– Empyema or Rheumatoid Arthritis

• pH < 7.2 Empyema• Triglycerides > 110 mg/dL

– Chylothorax

• Amylase – malignancy, pancreatic disease, esophageal

Other Useful Tests

• Pleural to blood HCT > 0.5– Hemothorax

• Cell Count– PMN predominate in parapneumonic pneumonia– Lymphocte predominate in malignancy, Tb, CABG– Eosinophills when blood or air in pleural space

• Fluid Culture– Grams stain, bacterial culture, acid fast bacilli

smear and culture, and fungal culture.

• Cytology for malignancy

Appearance Pleural Fluid

• Odour– Fetid = Empyema– Urine = Urinothorax

• Bloody r/o hemothorax• Milky appearance

– Chylothorax (Triglyceride > 110 mg/dL)– Pseudochylothorax (Cholesterol > 200 mg/dL)

• Pus – Empyema and complex pleural space

Pleural Fluid Appearance

54 yo female cough, pleuritic chest pain

Empyema

• Parapneumonic effusion– Any pleural effusion associated with bacterial or

viral pneumonia

• Loculated parapneumonic effusion– Not free flowing

• Multiloculated parapneumonic effusion– Noncommunicating compartments

• Empyema (fibrosuppurative exudate)– Pus is the pleural space, gram stain (+)– pH < 7.2, Glucose < 60 mg/dL, High LDH

Natural History Parapneumonic Effusion

• Exudative stage– Rapid accumulation of inflammatory fluid– Normal pH, Glucose, and LDH level– Antibiotics effective

• Fibropurulent stage– PMN’s, Fibrin deposition, loculations occur– Low pH and glucose, high LDH

• Organization stage (fibrothorax)– Fibroblast proliferation between pleural layers– Pleural peel develops, decortication required

Etiology Empyema

• Infectious Pneumonias– Staph aureus– Strep pneumonia– Gram negative bacilli– Tuberculous pleuritis (Uncommon in US)

• Thoracic trauma• Severe Sepsis

Management of Parapneumonic Effusions

• Selection of appropriate antibiotic coverage– Early administration improves outcome– Community acquired, healthcare acquired vs

hospital acquired pneumonias• Different organisms for each category• Community acquired = Strep pneumo• Health care acquired = Staph aureus• Hospital acquired = gram negative bacilli

– Severity of illness a factor

Pleural Fluid Management

• Observation– Defervesce quickly– Uncomplicated pleural effusion

• Therapeutic drainage (thoracentesis)– Early exudative phase

• Tube thoracostomy– Complex pleural fluid spaces

• VATS (Video assisted thoracoscopic sur)– Poor clinical response to above interventions

• Decortication: removal of pleural peel

Noninfectious Inflammatory Pleuritis

• Systemic Autoimmune disease– Systemic Lupus Erythematosus– Sjogren’s– Rheumatoid Arthritis– Wegener’s Granulomatosis

• Drug Induced (Nitrofurantion, Hydralazine)• Thoracic Radiation• Post cardiac injury syndrome• Pneumoconioses(asbestosis)• Uremia

• References– Eur Resp J 1997; 10: 476-481.– Clin Pulm Med 2003; 10: 336-342.– Clin Chest Med 2006; 27: 309-319.– Clin Chest Med 2006; 27: 157-180– Clin Chest Med 2006; 27: 369-381.