Empyema overview

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Empyema Microchapters

Patient Information

Overview

Classification

Subdural empyema
Pleural empyema

Differential Diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Prince Tano Djan, BSc, MBChB [2]

Overview

An empyema is a collection of pus within a pre-existing body cavity. It must be differentiated from an abscess, which is a collection of necrotic and suppurated tissue located in the parenchyma of an organ.[1] Empyema is most commonly used to refer to pus collection in the pleural cavity although several other organs can be affected example brain, gallbladder, joint and urinary bladder. Thoracic empyema arises from an infection within the lung, often associated with parapneumonic effusions. Parapneumonic effusions may be uncomplicated or complicated effusions. Complicated parapneumonic effusion results when bacteria invade the pleural space with a resultant formation of an empyema.

Historical Perspective

Pleural infection was first described by Hippocrates as far back as 460-370 B.C.[2] During this time open chest drainage was the sole treatment modality and was associated with high mortality. In 1873, Playfair gave the first description of a water-seal chest drainage system in the treatment of a child with thoracic empyema.[3] In 1875, Gotthard Bülau a German Internist described the use of closed water-seal chest drainage to treat an empyema, as an alternative to the standard rib resection and open tube drainage. He punctured the pleura membrane with trocar and introduced a rubber catheter into the pleural cavity. The free end of the catheter inserted in a bottle one-third full of solution allowing pus to flow freely from the chest into the bottle.[4][5] Closed chest tube drainage was experimentally practised during the influenza epidemic in 1917–19 when open surgical drainage was associated with a high mortality rate. This coincided with world war I and the resultant crisis of streptococcal pneumonia and empyema.[6] Closed chest tube drainage became the standard of treatment from late 1950.[7]

Classification

Empyema may be classified according to the etiology, anatomical location, and pathological course of the disease.[8] Primary thoracic empyema occurs most commonly as iatrogenic empyema without associated pneumonia whereas secondary empyema happens more commonly secondary to pneumonia. Empyema necessitans is a spontaneous discharge of an empyema that has burrowed through the parietal pleura into the chest wall to form a subcutaneous abscess that may eventually rupture through the skin.[9][10] On the basis of anatomical location, empyema may be classified depending on the affected organ for example; gallbladder empyema,[11][12] subdural empyema,[13][14] joint empyema[15][16][17] and empyema cystitis.[18][19] Empyema is mostly caused by bacteria. It may be tuberculous or nontuberculous. Tuberculous empyema is the most common cause of empyema necessitans with majority of affected patients being immunocompromised.[20][21] There are 3 stages of empyema which are important in terms of the laboratory findings. These are exudative, fibrinopurulent and organizing.[22]

Pathophysiology

The process leading to the formation of empyema involves migration of organisms into the pleural cavity. Lung parenchymal infection stimulates local pleural immune activation, neutrophil migration and release of inflammatory cellular components and toxic oxygen species, such as IL-6, IL-8 and tumour necrosis factor (TNF)-α.[23][24][25] These mediators promotes endothelial injury resulting in increased pleural membrane permeability and increased osmotic pressure.[22] With persistent inflammation, increased permeability of vascular and mesothelial membranes results in increased plasma leakage into the pleural cavity. Coagulation cascade when activated within the pleural cavity contributes to the development of a “fibrinopurulent” or “complicated” parapneumonic effusion. Fibrin is deposited over the pleural surfaces with fibrinous septae producing loculated effusions.[26][27]

Causes

Streptococcus pneumoniae was the most common bacteria found in empyemas before the development of antibiotics. More recently, however, anaerobes have become the predominant organism in culture positive empyemas (and therefore careful anaerobic cultures should always be sent when working up parapneumonic effusions). Mixed aerobic and anaerobic infections are also common. In general any bacteria can cause an empyema, however different bacteria are associated with different rates of empyema formation.[28] Some of the common bacteria causes include; bacteroides, fusobacterium, haemophilus influenzae, pneumococcal infections, staphylococcus aureus, streptococcus, and TB.

Differentiating Empyema overview from Other Diseases

Empyema must be diffrentiated from pneumonia, lung abscess, lung cancer and parapneumonic effusions on the basis of the presentation, physical examination findings, chest xray, ultrasound and CT scan findings. For instance on ultrasound, empyema is positive for suspended microbubble sign, air fluid level, curtains sign and loss of gliding sign but these are negative in a lung abscess.

Again empyema is differentiated from a lung abscess in that empyema on CT scan is seen as a lung mass whose cavity is regular with smooth well-defined boundary and shape changes with change in patient's position.[29] Mass may resolve on antibiotics. The split pleura sign is present[30] (most reliable sign to differentiate empyema from lung abscess).[31]

Epidemiology and Demographics

The incidence and prevalence of empyema has been increasing over the past 15 years. More than 40% of patients have preexisting comorbidities.[32] There have been a 26% increase in age and sex-standardized incidence rate from 8.7 per 100,000 person-years in 1997 to 11.8 per 100,000 person in 2011.[32] This increment is most notably among older people aged ≥ 80 years (87.3% [from 20.4 per 100,000 in 1997 to 38.2 per 100,000 in 2011]) compared with people aged 40 to 64 years (27.8% [from 10.7 per 100,000 in 1997 to 12.6 per 100,000 in 2011]).[32] Men are more commonly affected with empyema than women. The male to female ratio is approximately 1.7- to 3.1-fold higher in men than in women.[32] The rate of patients with empyema requiring hospitalization appear to be increasing in western populations, however updated population-based data are scanty. The few available data on adult empyema have reported increase between 30% and 97% over the past 15 years in the United States and Canada.[32][33] There is however a decreasing trend in the median days of hospital stay from 22 days 17 days.[32]

Risk Factors

Common risk factors in the development of empyema include:[34] Bacterial pneumonia, thoracic surgery[35] NSAIDs use during acute viral infection is associated with an increased risk of empyema in children,[36] Lung abscess, chest trauma,[37] and post-thoracostomy drainage.[38]

Screening

There is no established screening modality for empyema however, lateral chest x-ray is the initial imaging of choice in patients with pneumonia. It is superior in detecting parapneumonic effusions compared to anteroposterior chest x ray.[39]

Natural History, Complications, and Prognosis

If left untreated 40% of complicated pneumonia results in effusion with 60% resulting in the formation of empyema.[40] Empyema may result in the following complications; empyema necessitans,[10] imparired perfusion and ventilation of lungs as a result of pleural thickening and reduced lung function, necrotizing fasciitis of the chest wall,[21] bronchopulmonary fistula or alveolar-pleural fistula,[21][41] The prognosis of empyema after treatment is good however, the risk of permanent lung damage and mortality increase when empyema complicates pneumonia.[32][42] Advanced age and comorbidity are strong prognostic factors. Thirty-day mortality rate ranges from 1.2% in patients aged 15 to 39 years to 20.2% in those aged ≥ 80 years. Mortality also varies substantially according to level of comorbidity.[32]

Diagnosis

History and Symptoms

Symptoms of empyema may vary in severity. Most patients with empyema may prersent with fever and chills, cough, shortness of breath, pleuritic chest pain, anaerobic infections however, can be more indolent, with up to 70% of patients having symptoms for more than 1 week.[43][1] Additionally, these patients tend to have more constitutional symptoms including; excessive night sweating, weight loss

Physical Examination

On examination, the following findings may be seen:[43][9][44] lateral chest wall swelling and tenderness, clubbing of the fingernails, dull percussion note, reduced breath sounds on the affected side of the chest, egophony, coarse crackles, increased fremitus, mediastinal shift to opposite side with large empyema

Laboratory Findings

Diagnosis is confirmed by thoracentesis. Aspiration of the purulent fluid is necessary especially when condition is not resolving on antibiotics. The pleural fluid typically has a low pH (<7.20), low glucose (<60 mg/dL), and contains infectious organisms. Although the presence of pus or organisms on gram stain is extremely helpful in making a diagnosis of empyema, a positive bacteria culture from pleural fluid is not needed before diagnosis of empyema is comfirmed.[45][40]

Imaging Findings

Chest radiography is the initial imaging modality in evaluation of pleural disease.[46] Lateral view is superior in detecting parapneumonic effusions and empyema compared to anteroposterior chest x ray.[39] Chest X ray of empyema shows air-fluid level with continuous homogenous pattern from the mediastinum to the chest wall forming and obtuse angle with the lung parenchyma. Thoracic ultrasound have greater sensitivity in detecting pleural effusions than clinical examination or chest radiographs (AP or lateral).[47] Thoraxic ultrasound is the next prefered imaging test after chest xray.[48][47] Ultrasound in empyema is positive for suspended microbubble sign, air fluid level, curtains sign and loss of gliding sign.[49] Thoracic MRI may show an internally septated, thick wall, and heterogeneous mass especially in empyema necessitans[9] On Computed tomographic scan, empyema is seen as a lung mass whose cavity is regular with smooth and regular lumen and well-defined boundary. The shape changes with change in patient's position.[29] Mass on CT scan may resolve on antibiotics. The split pleura sign on CT scan is present (most reliable sign to differentiate empyema from lung abscess where it is absent).[30][31]

Other Diagnostic Studies

Leucocytosis as well as increased levels of pleural adenosine deaminase and pleural lactate dehydrogenase (usually above 1000) may provide additional diagnostic feature for empyema.[50]

Treatment

Medical Therapy

The mainstay of therapy for empyema includes:[51] controlling the infectious focus, drainage of fluid and pus, re-expansion of the lung. This involes the use of antimicrobial agents, thrombolytics,[52][53] and drainage of the pleural space.[54][8][55] Pharmacologic therapies for acute empyema include either Ceftriaxone, Nafcillin or Oxacillin, Vancomycin or Linezolid, or TMP-SMX. The preferred regimen for subacute and chronic empyema is a combination of Clindamycin and Ceftriaxone.

Surgery

Definitive surgical treatment for empyema entails drainage of the infected pleural fluid. A chest tube may be inserted, often using ultrasound guidance. Intravenous antibiotics are given. If this is insufficient, surgical debridement of the pleural space may be required.[51][55][54]Management strategies of Empyema necessitans with pulmonary involvement and lung abscess may involve thoracotomy with pulmonary resection in addition to extended duration antimicrobial therapy.[43][9]

Prevention

Early and effecient treatment of pleural effection have been found to prevent the development of empyema.[32][42]

References

  1. ↑ 1.0 1.1 Monteiro R, Alfaro TM, Correia L, Simão A, Carvalho A, Costa JN (2011). "[Lung abscess and thoracic empyema: retrospective analysis in an internal medicine department]". Acta Med Port. 24 Suppl 2: 229–40. PMID 22849907.
  2. ↑ FRANCE, JOHN (2010). [URL: http://www.jstor.org/stable/10.7722/j.ctt7zstnd Journal of Medieval Military History: Volume VIII] Check |url= value (help). Boydell Press, Boydell & Brewer. p. 206. ISBN 9781843835967.
  3. ↑ Munnell ER (1997). "Thoracic drainage". Ann Thorac Surg. 63 (5): 1497–502. PMID 9146363.
  4. ↑ Meyer JA (1989). "Gotthard Bülau and closed water-seal drainage for empyema, 1875-1891". Ann Thorac Surg. 48 (4): 597–9. PMID 2679468.
  5. ↑ Van Schil PE (1997). "Thoracic drainage and the contribution of Gotthard Bülau". Ann Thorac Surg. 64 (6): 1876. PMID 9436605.
  6. ↑ Peters RM (1989). "Empyema thoracis: historical perspective". Ann Thorac Surg. 48 (2): 306–8. PMID 2669652.
  7. ↑ Monaghan SF, Swan KG (2008). "Tube thoracostomy: the struggle to the "standard of care"". Ann Thorac Surg. 86 (6): 2019–22. doi:10.1016/j.athoracsur.2008.08.006. PMID 19022041.
  8. ↑ 8.0 8.1 Light RW (1995). "A new classification of parapneumonic effusions and empyema". Chest. 108 (2): 299–301. PMID 7634854.
  9. ↑ 9.0 9.1 9.2 9.3 Gomes MM, Alves M, Correia JB, Santos L (2013). "Empyema necessitans: very late complication of [[pulmonary tuberculosis]]". BMJ Case Rep. 2013. doi:10.1136/bcr-2013-202072. PMC 3863066. PMID 24326441. URL–wikilink conflict (help)
  10. ↑ 10.0 10.1 Ahmed SI, Gripaldo RE, Alao OA (2007). "Empyema necessitans in the setting of pneumonia and parapneumonic effusion". Am J Med Sci. 333 (2): 106–8. PMID 17301589.
  11. ↑
  12. ↑
  13. ↑
  14. ↑
  15. ↑
  16. ↑
  17. ↑
  18. ↑
  19. ↑
  20. ↑ Babamahmoodi F, Davoodi L, Sheikholeslami R, Ahangarkani F (2016). "Tuberculous Empyema Necessitatis in a 40-Year-Old Immunocompetent Male". Case Rep Infect Dis. 2016: 4187108. doi:10.1155/2016/4187108. PMC 4983337. PMID 27555974.
  21. ↑ 21.0 21.1 21.2 Nishihara T, Hayama M, Okamoto N, Tanaka A, Nishida T, Shiroyama T; et al. (2016). "Endoscopic Bronchial Occlusion with Silicon Spigots for the Treatment of an Alveolar-pleural Fistula during Anti-tuberculosis Therapy for Tuberculous Empyema". Intern Med. 55 (15): 2055–9. doi:10.2169/internalmedicine.55.6672. PMID 27477414.
  22. ↑ 22.0 22.1 Strange C, Tomlinson JR, Wilson C, Harley R, Miller KS, Sahn SA (1989). "The histology of experimental pleural injury with tetracycline, empyema, and carrageenan". Exp Mol Pathol. 51 (3): 205–19. PMID 2480911.
  23. ↑
  24. ↑
  25. ↑
  26. ↑ Mohammed KA, Nasreen N, Hardwick J, Van Horn RD, Sanders KL, Antony VB (2003). "Mycobacteria induces pleural mesothelial permeability by down-regulating beta-catenin expression". Lung. 181 (2): 57–66. doi:10.1007/s00408-003-1006-1. PMID 12953144.
  27. ↑ Mohammed KA, Nasreen N, Hardwick J, Logie CS, Patterson CE, Antony VB (2001). "Bacterial induction of pleural mesothelial monolayer barrier dysfunction". Am J Physiol Lung Cell Mol Physiol. 281 (1): L119–25. PMID 11404254.
  28. ↑ Brims FJ, Lansley SM, Waterer GW, Lee YC (2010). "Empyema thoracis: new insights into an old disease". Eur Respir Rev. 19 (117): 220–8. doi:10.1183/09059180.00005610. PMID 20956197.
  29. ↑ 29.0 29.1 Baber CE, Hedlund LW, Oddson TA, Putman CE (1980). "Differentiating empyemas and peripheral pulmonary abscesses: the value of computed tomography". Radiology. 135 (3): 755–8. doi:10.1148/radiology.135.3.7384467. PMID 7384467.
  30. ↑ 30.0 30.1 Stark DD, Federle MP, Goodman PC, Podrasky AE, Webb WR (1983). "Differentiating lung abscess and empyema: radiography and computed tomography". AJR Am J Roentgenol. 141 (1): 163–7. doi:10.2214/ajr.141.1.163. PMID 6602513.
  31. ↑ 31.0 31.1 Kraus GJ (2007). "The split pleura sign". Radiology. 243 (1): 297–8. doi:10.1148/radiol.2431041658. PMID 17392263.
  32. ↑ 32.0 32.1 32.2 32.3 32.4 32.5 32.6 32.7 32.8 Søgaard M, Nielsen RB, Nørgaard M, Kornum JB, Schønheyder HC, Thomsen RW (2014). "Incidence, length of stay, and prognosis of hospitalized patients with pleural empyema: a 15-year Danish nationwide cohort study". Chest. 145 (1): 189–92. doi:10.1378/chest.13-1912. PMID 24394842.
  33. ↑ Farjah F, Symons RG, Krishnadasan B, Wood DE, Flum DR (2007). "Management of pleural space infections: a population-based analysis". J Thorac Cardiovasc Surg. 133 (2): 346–51. doi:10.1016/j.jtcvs.2006.09.038. PMID 17258562.
  34. ↑
  35. ↑
  36. ↑
  37. ↑
  38. ↑
  39. ↑ 39.0 39.1 Moffett BK, Panchabhai TS, Nakamatsu R, Arnold FW, Peyrani P, Wiemken T; et al. (2016). "Comparing posteroanterior with lateral and anteroposterior chest radiography in the initial detection of parapneumonic effusions". Am J Emerg Med. 34 (12): 2402–2407. doi:10.1016/j.ajem.2016.09.021. PMID 27793503.
  40. ↑ 40.0 40.1 Perez VP, Caierão J, Fischer GB, Dias CA, d'Azevedo PA (2016). "Pleural effusion with negative culture: a challenge for pneumococcal diagnosis in children". Diagn Microbiol Infect Dis. 86 (2): 200–4. doi:10.1016/j.diagmicrobio.2016.07.022. PMID 27527890.
  41. ↑ Deschamps C, Bernard A, Nichols FC, Allen MS, Miller DL, Trastek VF; et al. (2001). "Empyema and bronchopleural fistula after pneumonectomy: factors affecting incidence". Ann Thorac Surg. 72 (1): 243–7, discussion 248. PMID 11465187.
  42. ↑ 42.0 42.1 Smith JA, Mullerworth MH, Westlake GW, Tatoulis J (1991). "Empyema thoracis: 14-year experience in a teaching center". Ann Thorac Surg. 51 (1): 39–42. PMID 1985571.
  43. ↑ 43.0 43.1 43.2 Atay S, Banki F, Floyd C (2016). "Empyema necessitans caused by actinomycosis: A case report". Int J Surg Case Rep. 23: 182–5. doi:10.1016/j.ijscr.2016.04.005. PMC 5022073. PMID 27180228.
  44. ↑ Kuan YC, How SH, Yeen WC, Ng TH, Fauzi AR (2011). "Empyema thoracis complicated by pneumothorax necessitans manifesting as lobulated, localized subcutaneous emphysematous swellings". Ann Thorac Surg. 91 (6): 1969–71. doi:10.1016/j.athoracsur.2010.11.075. PMID 21619994.
  45. ↑ Mavroudis C, Ganzel BL, Cox SK, Polk HC (1987). "Experimental aerobic-anaerobic thoracic empyema in the guinea pig". Ann Thorac Surg. 43 (3): 298–302. PMID 3548615.
  46. ↑
  47. ↑ 47.0 47.1 Eibenberger KL, Dock WI, Ammann ME, Dorffner R, Hörmann MF, Grabenwöger F (1994). "Quantification of pleural effusions: sonography versus radiography". Radiology. 191 (3): 681–4. doi:10.1148/radiology.191.3.8184046. PMID 8184046.
  48. ↑ Stavas J, vanSonnenberg E, Casola G, Wittich GR (1987). "Percutaneous drainage of infected and noninfected thoracic fluid collections". J Thorac Imaging. 2 (3): 80–7. PMID 3302292.
  49. ↑ Lin FC, Chou CW, Chang SC (2004). "Differentiating pyopneumothorax and peripheral lung abscess: chest ultrasonography". Am J Med Sci. 327 (6): 330–5. PMID 15201646.
  50. ↑ Ernam D, Atalay F, Hasanoglu HC, Kaplan O (2005). "Role of biochemical tests in the diagnosis of exudative pleural effusions". Clin Biochem. 38 (1): 19–23. doi:10.1016/j.clinbiochem.2004.09.023. PMID 15607312.
  51. ↑ 51.0 51.1 Reichert M, Hecker M, Witte B, Bodner J, Padberg W, Weigand MA; et al. (2016). "Stage-directed therapy of pleural empyema". Langenbecks Arch Surg. doi:10.1007/s00423-016-1498-9. PMID 27815709.
  52. ↑ Porcel JM, Valencia H, Bielsa S (2016). "Manual Intrapleural Saline Flushing Plus Urokinase: A Potentially Useful Therapy for Complicated Parapneumonic Effusions and Empyemas". Lung. doi:10.1007/s00408-016-9964-2. PMID 27866276.
  53. ↑ Rahman NM, Maskell NA, West A, Teoh R, Arnold A, Mackinlay C; et al. (2011). "Intrapleural use of tissue plasminogen activator and DNase in pleural infection". N Engl J Med. 365 (6): 518–26. doi:10.1056/NEJMoa1012740. PMID 21830966. Review in: Ann Intern Med. 2011 Dec 20;155(12):JC6-9
  54. ↑ 54.0 54.1 Ashbaugh DG (1991). "Empyema thoracis. Factors influencing morbidity and mortality". Chest. 99 (5): 1162–5. PMID 2019172.
  55. ↑ 55.0 55.1 Colice GL, Curtis A, Deslauriers J, Heffner J, Light R, Littenberg B; et al. (2000). "Medical and surgical treatment of parapneumonic effusions : an evidence-based guideline". Chest. 118 (4): 1158–71. PMID 11035692.


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