0071643192.pdf

Transudative Effusion

■ Occurs because of an imbalance between hydrostatic and oncotic pres-

sures in the pleural space

■ The main causes are CHF, cirrhosis, nephrotic syndrome, and PE.

Exudative Effusion

■ Occurs when inflammation →altered vascular permeability and protein-

rich pleural fluid

■ Common causes include malignancy, bacterial, and viral pneumonia, TB,

PE, pancreatitis, esophageal rupture, collagen vascular disease, chylotho-

rax, and hemothorax.

SYMPTOMS/EXAM

■ Dyspnea

■ Pleuritic chest pain

■ Dullness to percussion, ↓or absent fremitus, and ↓breath sounds on the

affected side

■ Findings of underlying disease process (eg, productive cough, fever, and

consolidation in parapneumonic effusion)

DIAGNOSIS

■ CXR:Upright CXR confirms diagnosis in most cases. Decubitus films

help determine if fluid is free-flowing or loculated. The presence of >1 cm

of fluid on decubitus CXR suggests the presence of a significant amount of

fluid.

■ Diagnostic thoracentesis:Perform on clinically significant effusions; ana-

lyze fluid to distinguish transudate from exudate using Light’s criteria (see

Table 10.16).

■ If exudative effusion is suspected or confirmed, additional pleural fluid

analysis should occur (see Table 10.17), guided by clinical suspicion for

underlying disease process.

■ Chest CT: Can confirm diagnosis and aid in differentiating underlying

disease process (eg, PE, malignancy)

TREATMENT

■ Transudative pleural effusion: Treatment is aimed at the underlying

cause with therapeutic thoracentesis if the patient is symptomatic.

■ Parapneumonic effusion: Chest tube placement for drainage of the

pleural space is indicated if there is evidence of empyema (pH <7.2, pus,

glucose<40 mg/dL, Gram stain ⊕).

■ Hemothorax:Drainage is required or fibrothorax will likely develop.

THORACIC AND RESPIRATORY

DISORDERS

TABLE 10.16. Light’s Criteria for Distinguishing Transudative From Exudative Effusion

Pleural fluid/serum protein ratio>0.5

Pleural fluid LDH>2/3 upper limit of serum reference range

Pleural fluid/serum LDH ratio>0.6

The fluid is an exudate if at least one of the above criteria is present.

The fluid is a transudate if none of the above criteria is present.

Drain a pleural effusion if pH

is<7.2, glucose is <60 mg/dL,

or Gram stain is ⊕.