Thoracic Surgery For Non-Neoplastic Disease. Empyema
EMPYEMA
10. What is an empyema, and what causes it?
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An empyema is a purulent (infected) effusion. Fluid or blood in the pleural space can be directly innoculated (with bugs) during surgery or trauma (33%) or by contamination from contiguous sites (50%) such as bronchopulmonary infection (most common). Most empyemas are parapneumonic, and the most commonly involved organisms are Staphylococcus aureus, enteric gram-negative bacilli, and anaerobes. Many times, infections are polymicrobial. Often there is no growth of an empyema culture because of effective antibiotic therapy or inadequate culture techniques, particularly with anaerobes.
11. What are the three stages of empyema development?
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They are the exudative stage (low viscosity fluid), fibrinopurulent stage (transitional phase with heavy fibrinous deposits and turbid fluid), and organizing stage (capillary ingrowth with lung trapping by collagen). This process usually evolves over 6 weeks.
12. How is an empyema diagnosed?
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Characteristic clinical and radiographic findings are used. Computed tomography (CT) scan is very helpful in defining loculations. Thoracentesis may reveal frank pus, and Gram stain shows many white blood cells (WBCs) and organisms. Biochemical analysis varies, but it is generally an exudate with a low pH (< 7), high LDH (> 1000 IU/L), and low glucose (< 50 mg/dL).
KEY POINTS: THORACIC SURGERY FOR NON-NEOPLASTIC DISEASE
1. Surgery is indicated for complications of tuberculosis, with the most common indication in the United States being multiple drug-resistant tuberculosis with destroyed lung and persistent cavitary disease.
2. An empyema is a purulent (infected) effusion.
3. The three stages of empyema are the exudative stage (low viscosity fluid), fibrinopurulent stage (transitional phase with heavy fibrinous deposits and turbid fluid), and organizing stage (capillary ingrowth with lung trappng by collagen).
13. How should an empyema be treated?
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Antibiotic therapy directed by Gram stain and culture. If early, tube thoracostomy may be curative. Conversion to open tube drainage (empyema tube) may be necessary if persistent purulent drainage occurs. Instillation of fibrinolytic enzymes (e.g., streptokinase or TPA) may be helpful. An infected loculated (lots of discontinuous cystic pockets) effusion <14 days old should undergo video-assisted thoracoscopic surgery (VATS) decortication (i.e., resection of the thickened, adherent peel). The probability of conversion to open thoracotomy increases with the age of the effusion or empyema.
14. What is a decortication?
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The cortex is the outside wall or peel of the empyema (like an orange). Thus, decortication is the surgical release and removal of the abscess cavity walls. Successful decortication allows the lung to expand and fill the entire pleural space; if complete expansion does not occur, then the effusion may recur, and continued lung trapping is likely.
15. What are the complications of an empyema left untreated?
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The most common is pulmonary fibrosis with lung trapping and resultant dyspnea. Others include contraction and deformity of the chest wall, spontaneous drainage through the chest wall (empyema necessitans), bronchopleural fistula, osteomyelitis, pericarditis, mediastinal or subphrenic abscess, sepsis, and death. None of these outcomes is particularly appealing, so in the absence of overwhelming contraindications, all empyemas warrant therapy.
References
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BIBLIOGRAPHY
1. American Thoracic Society: Diagnosis and treatment of disease caused by nontuberculous mycobacteria. Am J Respir Crit Care Med 156(suppl 2 pt 2):S1-S25, 1997.
2. Colice GL, Curtis A, Deslauriers J, et al: Medical and surgical treatment of parapneumonic effusions: An evidence-based guideline. Chest 118:1158-1171, 2000. Medline Similar articles Full article
3. de Hoyos A, Sundaresan S: Thoracic empyema. Surg Clin North Am 82:643-671, 2002. Medline Similar articles
4. Mault JR, Pomerantz M: Mycobacterium tuberculosis and other mycobacteria. Chest Surg Clin North Am 9:227-238, 1999.
5. Pomerantz M, Brown J: Surgery of pulmonary mycobacterial disease. In Kaiser LR, Kron IL, Spray TL (eds): Mastery of Cardiothoracic Surgery. Philadelphia, Lippincott-Raven, 1998, pp 265-271.
6. Wiedeman HP, Rice TW: Lung abscess and empyema. Semin Thorac Cardiovasc Surg 7:119-128, 1995.
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Abernathy’s Surgical Secrets, Updated Edition (Book w / Student Consult)
Author / s: Harken Alden H., Abernathy Charles, Moore Ernest Eugene
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