What Is Empyema?
Empyema refers to the collection of pus in the pleural cavity. The pleural cavity is the space between the outermost layer of the lungs and the inner lining of the chest wall. This space helps the lungs to expand and contract. There is a small amount of fluid present in the pleural space naturally. Empyema happens when there is extra fluid in the pleural space.
What Are the Symptoms of Empyema?
Symptoms of empyema may include:
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Fever.
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Chest pain.
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Having pneumonia with no improvement.
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Cough.
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Pus in mucus.
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Difficulty breathing.
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Dull sound when tapping chest.
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Decreased breathing sounds.
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Crackling sound in the chest.
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Weight loss.
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In older people, anemia and exhaustion are seen.
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The fluid buildup in the pleural space can be seen in the X-ray.
On physical examination,
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Dullness to percussion in the affected area.
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Egophony (increased resonance of lung sounds).
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Increased palpable fremitus.
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Fine crackles.
What Are the Causes of Empyema?
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Pneumonia is the major cause of empyema.
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Microorganisms.
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Injury or trauma.
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Thoracic surgery is performed on chest organs such as the lungs, heart, and esophagus. Medical instruments can transfer bacteria into the pleural cavity.
What Are the Types of Empyema?
Without treatment, empyema can progress into three stages:
Stage 1: Simple Empyema:
Simple empyema is the initial stage where the extra fluid builds up in the pleural cavity. It is also called the exudative phase. The fluid collected can become infected and may contain pus. In the exudate, there are greater than 15000 leukocytes per mL.
Stage 2: Complicated Empyema:
The extra fluid collected in the pleural cavity thickens and forms pockets. The fibrous septa forms into localized pus pockets, and hence this stage is also called the fibrinopurulent stage.
Stage 3: Frank Empyema:
The infected fluid causes scarring in the inner layers of the lungs. Scar causes difficulty in breathing as it keeps the lungs from inflating properly. The other name of this stage is called the organizing phase.
What Are the Risk Factors for Empyema?
The major risk factor in causing empyema is the history of recent pneumonia. Other factors include:
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Having a recent hospital stay.
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Being older than 70.
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Undergone chest surgery or trauma.
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Previous cancer.
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Administration of intravenous drug use may also be the risk factor for simple empyema.
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Alcoholism.
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Bronchiectasis is a condition where the lung airways are damaged, making it hard to clear mucus.
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Chronic obstructive pulmonary disease (COPD) is a group of lung diseases that block the airway making it difficult to breathe.
What Are the Complications of Empyema?
Complex empyema manifests in the later stage of the disease. The inflammation seems to be more severe in this stage. There is scar tissue formation that divides the chest cavity into smaller cavities. This formation is called loculation, and it is more difficult to treat. The progression of the infection can lead to the formation of a thick peel over the pleura called a pleural peel. Surgery is indicated in this case as it prevents the lungs from expanding.
In rare cases, complex empyema progresses to more severe complications. These include sepsis and pneumothorax (collapsed lung).
Sepsis:
The symptoms of sepsis include:
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Chills.
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High fever.
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Fast heart rate.
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Low blood pressure.
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Rapid breathing.
Collapsed Lung:
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Sudden sharp chest pain.
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Shortness of breath gets worse when coughing or breathing.
How to Diagnose Empyema?
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A complete medical history and physical examination are carried out.
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Stethoscope - To listen to any abnormal sounds in the lungs.
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Chest X-rays and Computed Tomography (CT) - The initial investigation for suspected empyema remains chest X-ray, though it cannot differentiate from parapneumonic effusion. Chest computed tomography and magnetic resonance imaging (MRI) do not provide additional information hence should not be performed routinely. In CT scans, empyema fluid has a radiodensity of about 0 to 20 Hounsfield units (HU) but gets over 30 HU when becoming more thickened with time. CT scans show pockets of liquid in the pleural cavity.
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Chest Ultrasound - It is more sensitive and can show any extra fluid in the area.
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Blood and Sputum Culture - It is performed in acquired pneumonia patients needing hospitalization. Since the sensitivity of pleural effusion is generally low, maybe partly due to the administration of antibiotics. The culture yield can be increased from 44 to 69 % if the pleural fluid is injected into blood culture bottles immediately after aspiration.
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Polymerase Chain Reaction or Antigen Detection - This method increases the diagnostic rates for specific pathogens, especially for Streptococcus pneumoniae, Streptococcus pyogenes, and Staphylococcus aureus.
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Pneumococcal empyema can be rapidly tested with Pneumococcal antigen detection in pleural fluid samples by latex agglutination.
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The most commonly used standard criteria for empyema are pleural effusion with the pus formation, a positive gram stain in the pleural fluid culture, or a pleural fluid pH should be under 7.2 with normal peripheral blood pH. Therefore, clinical guidelines for adults advocate diagnostic pleural fluid aspiration in patients with pleural effusion associated with sepsis or pneumonic illness.
The thoracentesis procedure is carried out by inserting a needle through the back of the rib cage into the pleural space to take a sample of fluid. The fluid is then evaluated under a microscope for the presence of bacteria, protein, and other cells.
What Is the Treatment for Empyema?
Pleural Fluid Drainage:
Empyema is an indication of immediate chest tube drainage. Pleural fluid drainage improves the resolution of infection and shortens hospital admission. In patients with non-purulent, culture-negative fluid, a pH value of greater than 7.2 indicates necessary for chest tube drainage.
Fibrinolytic Therapy:
Patients presenting with dense, lumpy nature of pleural fluid and also with possible septation and loculation are indicated for fibrinolytic therapy or mucolytic therapy. This therapy increases drainage and has a favorable prognosis. Unfortunately, though, intrapleural fibrinolysis with urokinase has serious side effects. Nevertheless, it decreased the need for surgery.
Antibiotics:
Certain antibiotics such as Penicillin, Metronidazole, Ceftriaxone, Gentamicin, Vancomycin, Clindamycin, and Ciprofloxacin show better results. These drugs have resulted in clear pleural fluid and a good level of empyema penetration. Aminoglycosides are avoided as they have poor penetration into pleural space. Based on the clinical, biochemical, and radiological responses, oral antibiotics are continued for one to four weeks.
Surgery:
Surgical intervention is the last resource. The main aim of surgical therapy is to evacuate pus from the pleural cavity and lung expansion. Video-assisted thoracotomy (VATS) is the initial step that is less invasive, minimal blood loss, less pain, short hospitalization, better respiratory outcome, and decreased 30 days mortality.
Conclusion:
Empyema is a common diagnosis in hospitals. The prognosis for patients with early empyema is excellent. An inter-professional team approach can manage this condition.
