What are the differences in physical exam findings between pneumonia and pleural effusion?

From the Guidelines

Pneumonia and pleural effusion can be differentiated through physical examination findings, with pneumonia typically presenting with bronchial breath sounds, increased vocal resonance, and crackles, whereas pleural effusion is characterized by decreased or absent breath sounds, dullness to percussion, and a fluid level that shifts with patient positioning. The key differences in physical exam findings between pneumonia and pleural effusion are:

• Percussion: dullness over the affected area in pneumonia, but more pronounced dullness or flatness in pleural effusion 1
• Breath sounds: bronchial with increased vocal resonance in pneumonia, but decreased or absent in pleural effusion 1
• Vocal resonance and tactile fremitus: increased in pneumonia, but diminished or absent in pleural effusion 1
• Fluid level: typically present in pleural effusion, with a stony dullness that shifts with patient positioning 1
• Tracheal deviation: uncommon in pneumonia, but may occur with large effusions 1
• Chest expansion: decreased on the affected side in both conditions, but often more pronounced with large effusions 1 Understanding these differences is crucial for accurate diagnosis and management, as pneumonia requires antimicrobial therapy, while pleural effusion may need drainage procedures depending on the underlying cause 1.

From the Research

Physical Exam Findings

The physical exam findings for pneumonia and pleural effusion can be distinguished by the following characteristics:

• Pneumonia typically presents with findings such as:
  • Crackles or rales on lung auscultation
  • Dullness to percussion over the affected area
  • Increased fremitus (vibration) on palpation
• Pleural effusion, on the other hand, may present with:
  • Dullness to percussion over a larger area
  • Decreased or absent breath sounds over the affected area
  • Decreased fremitus (vibration) on palpation

Diagnostic Considerations

When differentiating between pneumonia and pleural effusion, it is essential to consider the following:

• A pleural effusion can develop in up to 40% of cases of pneumonia 2
• The presence of a pleural effusion can increase the morbidity and mortality rates in patients with pneumonia 2
• Precise differential diagnostic categorization is essential, as the treatment and prognosis of pleural effusion largely depend on its cause 3

Clinical Implications

The management of parapneumonic pleural effusion involves early diagnosis, adequate empiric antibiotic cover, and appropriate risk categorization 4

• High-risk patients require safe and expedient drainage of the infected pleural space
• The management options include thoracentesis, tube thoracostomy, adjunctive intrapleural fibrinolytic therapy, and surgical drainage

Treatment Approaches

The treatment of pleural effusion ranges from pleurodesis, to thoracoscopy and video-assisted thoracoscopy, to the placement of a permanently indwelling pleural catheter 3

• The proper treatment of pleural effusion can be determined only after meticulous differential diagnosis
• The range of therapeutic options has recently become much wider, with ongoing research expected to provide more data on diagnostic testing, pleurodetic agents, and interventional techniques 3, 5