From the Guidelines
To diagnose empyema, clinicians should focus on identifying frank pus in the pleural fluid, a positive Gram stain or culture, and a clinical presentation that includes fever, cough, dyspnea, pleuritic chest pain, and malaise, as these are indicative of empyema and require prompt chest tube drainage. When evaluating a patient for empyema, it is essential to consider the clinical features and examination findings that distinguish it from other conditions. Patients with empyema often present with a history of recent pneumonia, thoracic surgery, trauma, or procedures, and may have risk factors such as immunosuppression, alcoholism, diabetes, or aspiration risk 1.
Key Clinical Features
- Fever
- Cough
- Dyspnea
- Pleuritic chest pain
- Malaise
- Recent pneumonia, thoracic surgery, trauma, or procedures
- Risk factors such as immunosuppression, alcoholism, diabetes, or aspiration risk
Physical Examination Findings
- Decreased breath sounds
- Dullness to percussion
- Decreased tactile fremitus over the affected area
- Tachypnea
- Tachycardia
- Hypoxemia in severe cases
Diagnostic Criteria
- Purulent pleural fluid (frank pus)
- Positive Gram stain or culture
- Pleural fluid analysis showing pH < 7.2, glucose < 60 mg/dL, and LDH > 1000 IU/L, although no additional biochemical tests are necessary on pleural fluid for empyema 1.
It is crucial to recognize empyema early, as delayed diagnosis can increase morbidity and mortality, and requires chest tube drainage 1. The presence of anaerobes, which may be found in up to 76% of cases, can lead to empyema without other aerobic co-pathogens, and is more likely to have an insidious clinical onset, with less fever, greater weight loss, and is more common following possible aspiration pneumonia and with poor dental hygiene 1.
From the Research
Clinical Features of Empyema
To diagnose a patient with empyema, the following clinical features should be asked and examined:
- Dyspnea, initially on exertion 2, 3
- Dry cough 2
- Pleuritic chest pain 2
- Productive cough associated with fever, weakness, and progressively worsening dyspnea on exertion 4
- Rhonchi in the right upper lobe and diminished breath sounds throughout the right lung 4
Physical Examination
A physical examination of the chest should be conducted as part of a comprehensive respiratory assessment, including:
Diagnostic Evaluation
The diagnostic evaluation of empyema includes:
- Thoracocentesis to determine the etiology of the pleural effusion 2
- Laboratory testing to distinguish pleural fluid transudate from an exudate 2
- Chemical and microbiological studies, as well as cytological analysis 2
- Immunohistochemistry to increase diagnostic accuracy 2
- Point of care ultrasound (POCUS) to diagnose empyema, especially in cases of diagnostic uncertainty 4