The incidence of pleural infection (empyema and complicated parapneumonic effusions) is rising
Although pleural infection complicates less than 10% of pneumonia-related hospital admissions, the incidence is rising globally.1 In Ontario (1996–2015), cases increased from 2.9 to 6.7 per 100 000.2 This may be because of increasing older and immunosuppressed populations. 1 Pleural infection is associated with longer hospital stays and 5%–15% mortality.1,2
Diagnosis requires thoracentesis and pleural fluid analysis with cultures1,3
Because no radiologic sign can confidently exclude pleural infection, thoracentesis is essential for parapneumonic effusions large enough to be sampled based on ultrasonography.1,3 The presence of pus, a positive gram stain or pleural culture result, or a pH level of 7.2 or lower is diagnostic of pleural infection.3 Inoculating pleural fluid in blood culture bottles increases microbiologic yield over regular fluid culture from 38% to 59%.4 Pleural fluid (5–10 mL) should be sent in sterile containers (for gram stain) and blood culture bottles to increase yield.3,4 If less than 5 mL is obtained, blood culture bottles are the preferred medium.3,4
Empiric antibiotics must include anaerobic coverage, but targeting atypical bacteria is not required1,3
Pleural infection is commonly polymicrobial, with anaerobes present in more than 30% of cases, and atypical bacteria (e.g., Mycoplasma, Legionella, Chlamydophila) are rarely implicated.4,5 Empiric treatment for community-acquired cases includes ceftriaxone plus metronidazole.1,3 Treatment is continued for 2–6 weeks, depending on the response.1,3 Given difficulty in culturing anaerobes, anaerobic coverage is continued throughout treatment.1
Guidelines recommend 12–14F chest tubes for drainage1,3
Prompt drainage is vital to remove infected fluid, promote lung expansion, and reduce morbidity and mortality.1,3 Chest tubes larger than 12–14F increase pain without improving outcomes, whereas smaller ones have higher rates of blockage and dislodgement.1,3
Pleural infections unresponsive to chest tube drainage may require surgery or intrapleural fibrinolytics1,3
Patients with incomplete evacuation or signs of persistent infection after 48 hours may need intrapleural fibrinolytics, surgery, or prolonged antibiotic treatment.1,3 Respirologists and thoracic surgeons can help in early identification and management; early referral is therefore important.
Footnotes
Competing interests: Stéphane Beaudoin reports an unrestricted education grant from Olympus and honoraria from Sanofi. Amr Alwakeel reports grants from AstraZeneca; consulting fees from Sanofi; payment or honoraria from Olympus, AstraZeneca, GSK, Hikma, and Sanofi; support for attending meetings or travel from GSK, AstraZeneca, Sanofi, and Boehringer Ingelheim; and board participation for Sanofi. Dr. Alwakeel also reports a leadership role with Saudi Group for Interventional Pulmonology and stock or stock options with Merck, 3M, Pfizer, AbbVie, Medtronic, Dexcom, Organon, and Solventum (Intuitive Surgical). No other competing interests were declared.
This article has been peer reviewed.
References
- 1.Bedawi EO, Ricciardi S, Hassan M, et al. ERS/ESTS statement on the management of pleural infection in adults. Eur Respir J 2023;61:2201062. [DOI] [PubMed] [Google Scholar]
- 2.Nayak R, Brogly SB, Lajkosz K, et al. Two decades of thoracic empyema in Ontario, Canada. Chest 2020;157:1114–6. [DOI] [PubMed] [Google Scholar]
- 3.Roberts ME, Rahman NM, Maskell NA, et al. British Thoracic Society Guideline for pleural disease. Thorax 2023; 78(Suppl 3): s1–42. [DOI] [PubMed] [Google Scholar]
- 4.Menzies SM, Rahman NM, Wrightson JM, et al. Blood culture bottle culture of pleural fluid in pleural infection. Thorax 2011;66:658–62. [DOI] [PubMed] [Google Scholar]
- 5.Kanellakis NI, Wrightson JM, Gerry S, et al. The bacteriology of pleural infection (TORPIDS): an exploratory metagenomics analysis through next generation sequencing. Lancet Microbe 2022;3:e294–302. [DOI] [PMC free article] [PubMed] [Google Scholar]