Pleural Diseases: Anatomy, Physiology, Pneumothorax, Empyema thoracis and Pleural Effusion Download Power Point File
. Empyema is defined as a collection of pus in the pleural space OR Pleural Cavity.
Pleural Cavity is the space between the parietal and visceral pleura.
It is a potential space because it contains a thin film of serous fluid.
History of Pleural Infection
Imhotep is an Egyptian physician he described Empyema in 3000 BC, but Hippocrates first described the severe nature of thoracic Empyema more than 2400 years ago.
What are the causes of Empyema?
First
You have to know that Empyema is not a primary disease; it is a secondary disease.
Causes of Empyema includes:
1-Pnemonia
A parapneumonic pleural effusion is the most common cause of empyema. The majority resolve with antibiotic therapy. Postpneumonic empyema forms when bacteria infect the pleural fluid or pleural space.
2. Postsurgical empyema
Empyema may occur after certain surgeries. It represents 20% of cases of empyema and can follow surgery to the mediastinum, esophagus, and lungs, most commonly the following pneumonectomy.
3. It also may occur after rupture of lung abscess or infected pleural bleb, inhaled foreign bodies or bronchopleural fistula.
4. Empyema may also result from
- thoracic trauma, ruptured esophagus.
- pericarditis, abdominal processes such as cholangitis, and diverticulitis.
- with translocation of bacteria across the diaphragm, mediastinitis, chest wall or spine osteomyelitis.
5.iatrogenic causes
Such as
- Esophageal perforation during esophagoscopy
- Repeated Thoracocentesis
- Post-pneumonectomy
- Post-thoracotomy
Pathogenesis of Empyema
Classically, the development of empyema occurs in three clinical stages:
Stage I: acute exudative phase
- Typically occurs 2–5 days after pneumonia.
- Accumulation of fluid with low cellular content and viscosity.
- This phase characterized by low WBC, LDH, Glucose, and a normal pH.
- It can be successfully treated with antibiotics only.
Stage II: fibrinopurulent phase
- Typically occurs 5–14 days after pneumonia.
- Turbid or purulent fluid with heavy fibrin deposits.
- The appearance of simple loculations and septations.
- May have bacterial invasions, and high numbers of polymorphonuclear leukocytes (PMNs) and lymphocytes.
- Characterized by low pH, glucose, and increased LDH.
- Antibiotics and chest tube drainage is required ± VATS decortication.
Stage 3
chronic organizing phase
is characterized by
• Lung trapping by collagen, dense fibrous visceral and parietal pleural peel with
ingrowth of fibroblast and capillaries.
This phase will need
• Antibiotics and aggressive decortications, generally by thoracotomy.
• Bacteriology.
Many Kinds of bacteria can infect pleura or pleura fluid:
Includes staphylococcus, Haemophilus influenza, Gram –ve bacilli, Streptococcus pneumonia, Streptococcus pyogens, and Mycoplasma.
Note that
• if the empyema has been present for >2 weeks has a higher risk of conversion from VATS to open for decortication.
How to diagnose Empyema
Clinical Presentation
Patients may complain of
- Fever.
- Productive cough.
- Dyspnea.
- Chest wall pain.
- Malaise, and Fatigue.
Physical examination may reveal
- Decreased Ipsilateral Chest Wall Expansion.
- Egophony.
- Dullness to Percussion.
- Chest Wall Tenderness.
On Investigation:
• CXR, PA and lateral, and/or decubitus films to determine loculation.
• Chest CT: provides anatomy, and helps planning for chest tube placement of surgery, as well as showing thickened pleural peel, and presence of calcifications in the peel which help determine if thoracotomy rather than VATS necessary.
• Thoracentesis: Gram’s stain and culture, Light’s criteria distinguishes transudative effusion from exudative:
• Exudative if specific gravity is >1.02, Protein content >2.0 g/dL, and at least one of the following: ratio of pleural fluid protein to serum >0.5, ratio of pleural fluid LDH and serum >0.6, total pleural fluid LDH >2/3 upper limit of normal, ratio of pleural fluid albumin and blood <1.
Treatment
Stage I
• Sensitivity-appropriate antibiotics.
Stage II
• Chest tube drainage.
• Thrombolytics most likely to be effective during early stage empyema and should be reserved for patients who are poor surgical candidates.
Stage III and failure of stage II to resolve:
• If pleural space drainage is ineffective, or the effusion has loculated appearance on imaging, a VATS decortication should be performed without delay.
• If complete lung expansion is not achieved by VATS, then should convert to open thoracotomy: in processes that have been going >14 days, or in patients who have chest wall tenderness, need for conversion for open thoracotomy is higher.
• Open decortication indicated for late stage II, stage III, and incomplete lung expansion with VATS.
• Chest wall window (Eloesser flap) may be required if lung
cannot expand and empyema chronically reaccumulates, or in the case of a bronchopleural fistula that cannot be closed.
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