Pleural Effusions

The Pleura

Pleural Pathophysiology

1. Transpleural pressure imbalance

2. Increased capillary permeability

3. Impaired lymphatic drainage

4. Transdiaphragmatic movement of fluid

5. Pleural effusions of extravascular origin (chylothorax)

On CXR

Differential Diagnosis1. Transpleural pressure imbalance

• CHF

2. Increased capillary permeability

• PNA

3. Impaired lymphatic drainage

• Malignancy

• Late PNA (fibrin)

4. Transdiaphragmatic movement of fluid

• Hepatic Hydrothorax

• Peritoneal dialysis

5. Pleural effusions of extravascular origin (chylothorax)

Differential Diagnosis - CompleteCHF

Hepatic Hydrothorax

PD

Pancreatitis

Lung/Liver abscess

Chylous ascites

Malignancy

Meig’s syndrome (ascites, benign ovarian tumor)

Parapneumonic

Pulmonary embolism

TB

Hypoalbuminemia/Nephrotic syndrome

Atelectasis/Trapped Lung

Asbestosis

Rheumatoid lung

Yellow Nail Syndrome

Duropleural fistula

SVC obstruction

Sarcoidosis

Esophageal perforation

Lupus pleuritis

Constrictive pericarditis

Post-cardiac surgery syndrome

Rule of Thumb – Treat underlying disease

CHF

Hepatic Hydrothorax

PD

Pancreatitis

Lung/Liver abscess

Chylous ascites

Malignancy

Meig’s syndrome (ascites, benign ovarian tumor)

Parapneumonic

Pulmonary embolism

TB

Hypoalbuminemia/Nephrotic syndrome

Atelectasis/Trapped Lung

Asbestosis

Rheumatoid lung

Yellow Nail Syndrome

Duropleural fistula

SVC obstruction

Sarcoidosis

Esophageal perforation

Lupus pleuritis

Constrictive pericarditis

Post-cardiac surgery syndrome

Thoracentesis – Diagnostic and Therapeutic

From UpToDate…

INDICATIONS — Pleural effusions are usually detected by physical examination and then confirmed radiographically. Most patients who have a pleural effusion should undergo diagnostic thoracentesis to determine the nature of the effusion (ie, transudate, exudate) and to identify potential causes (eg, malignancy, infection).

Thoracentesis – Diagnostic and Therapeutic

What to send?

Thoracentesis – Diagnostic and Therapeutic

What to send?

•Cell count

•Cytology

•pH/glucose

•Amylase

•Triglycerides

•ADA

•Gram and Culture (bacterial, viral, fungal, AFB)

Thoracentesis – Diagnostic and Therapeutic

Reexpansion Pulmonary Edema

If more than 1 liter of pleural fluid is removed at a time during a thoracentesis or from a chest tube RPE may result.

RPE may present as asymptomatic radiographic changes or as complete cardiopulmonary collapse. Mortality rate is 20%.

Pleural Fluid Diagnostics

1. Transpleural pressure imbalance (transudate)

2. Increased capillary permeability (exudate)

3. Impaired lymphatic drainage (exudate)

4. Transdiaphragmatic movement of fluid (transudate)

5. Pleural effusions of extravascular origin (either)

Pleural Fluid Diagnostics

1. Transpleural pressure imbalance (transudate)

2. Increased capillary permeability (exudate)

3. Impaired lymphatic drainage (exudate)

4. Transdiaphragmatic movement of fluid (transudate)

5. Pleural effusions of extravascular origin (either)

Transudates are caused by:• Increased Starling forces

• Increased systemic capillary forces (increased rate of filtration)

• Increased systemic venous HTN (not really)

• Pulm venous HTN (CHF)

• Fistula or increased compartment pressure

Exudates are caused by:• Impaired protein and cell clearance from pleural space

• Leaky mesothelium

Pleural Fluid Diagnostics

Light’s Criteria: Effusion is likely exudative if at least one of the following exists:

• The ratio of pleural fluid protein to serum protein is greater than 0.5

• The ratio of pleural fluid LDH and serum LDH is greater than 0.6

• Pleural fluid LDH is greater than 0.7 times the normal upper limit for serum

Lights diagnosis approx 20% of transudates as exudates.

Modified Light’s Criteria: Effusion is likely exudative if at least one of the following exists:

• The ratio of pleural fluid protein to serum protein is greater than 0.5

• The pleural fluid LDH is greater than 0.67 the upper limit of normal serum concentration

Pleural Fluid DiagnosticsExudate Characteristics

Usually > 1000 nucleated cells

>50,000 nucleated cells is indicative of empyema

< 5000 nucleated cells with mononuclear predominance indicated TB

>80% lymphocytes indicative of transplant rejection, lymphoma, post-CABG, sarcoid, TB, fungal infection, yellow nail syndrome

>10% eosinophils indicative of abestosis, carcinoma, churg-strauss, hemothorax, lymphoma, parasites, PE, sarcoid, TB

Pleural Fluid Diagnostics