Recent developments in the management of pleural infection: A comprehensive review

Comparison of outcome between sole operation and operation after tube thoracostomy in late phase empyema

Empyema is a severe and potentially life-threatening condition characterized by infection in the pleural cavity with pus collection. Treatment options include antibiotics, tube thoracostomy, video-assisted thoracic surgery (VATS) decortication, or open thoracotomy. This study investigated whether decortication without pre-operative tube thoracostomy results in better outcomes for stage II and III empyema. We included 1042 patients with stage II or III empyema who underwent surgical decortication from January 2012 to December 2021. Among these patients, 713 underwent sole operation, and 329 underwent operation after tube thoracostomy. Patients were classified into two groups: sole operation (713 patients) and operation after tube thoracostomy (329 patients). Primary outcomes were peri-operative and in-hospital characteristics. Secondary outcomes analyzed 1-year overall survival rate and 1-year event-free survival. After 1:1 propensity score matching, 620 patients were included, with each group consisting of 310 patients. The sole operation group had significantly lower hospital mortality and 30-day re-intervention rates and shorter time between diagnosis and operation, operation time, ICU stay, ventilator duration, and hospital stay. The sole operation group also had higher 1-year overall survival and 1-year event-free survival. The first intervention for advanced-stage empyema is crucial. Even when patients ultimately require surgery, pre-operative tube thoracostomy could lead to poorer outcomes. Direct surgical management for stage II and III empyema is simpler and more effective.

Pleural fluid agitation for improving the microbiologic diagnostic yield in pleural infection: a feasibility study

BACKGROUND

Pleural infection is a commonly encountered respiratory disease but in > 40% the underlying microbiologic etiology is unknown. This feasibility study aims to investigate whether pleural fluid agitation prior to sample aspiration is safe and can improve the diagnostic yield of microbiologic analysis.

METHODS

Thirty adult patients with pleural infection, based on clinical, imaging and biochemical evidence, were included in this feasibility study. Ultrasound guided thoracentesis was performed with an initial standard aspiration sampling technique, followed by pleural fluid agitation into the pleural cavity for 3-5 cycles before collecting the agitated fluid. Coded samples were sent for biochemical and microbiologic analysis with culture in aerobic and anaerobic media.

RESULTS

No complications were encountered with the pleural fluid agitation technique. Overall, 14 (46.6%) of patients had a positive pleural fluid culture. No yield discordance was noted between the standard and the agitated pleural fluid sampling techniques except for 1 extra agitated sample growing klebsiella pneumoniae and another agitated sample with mixed infection showing an additional anaerobic bacterial growth. Four (30.8%) of the 13 concordantly positive samples showed heavier bacterial growth in the agitated samples using semi-quantitative culture scoring.

CONCLUSION

Pleural fluid agitation was safe but didn't significantly add to the microbiologic yield in pleural infection. However, higher bacterial growth in almost one third of positive samples suggests a potential effect for further investigation in a larger study. Despite being safe, pleural fluid agitation resulted in no significant improvement in the microbiologic yield among pleural infection. However, agitated samples grew more bacteria in almost a third of the positive samples suggesting a signal for further investigation in a larger study.

STUDY REGISTRATION

Clinicaltrials.gov - NCT05702580, 23/12/2022.

The incidence of pleural infections in Finland

BACKGROUND

The incidence of pleural infections appears to be increasing in Western countries for unclear reasons. The aim of the study was to describe the incidence and treatment patterns of pleural infections in Finland over three decades.

METHODS

Data regarding each treatment episode for pleural infections in the Finnish special medical care between January 1994 and December 2016 was obtained from a national database and compared to the demographics of Finnish residents obtained from the national census bureau. The annual incidence rates, type of treatment given, as well as the lengths of the hospitalization were analyzed.

RESULTS

A total of 28,463 episodes were reported, of which 55% were inpatient episodes. Of these, 76% concerned males, and the median age of patients was 60 (interquartile range 49-70) years. The overall incidence of pleural infections was 23.4 per 100.000 patient-years, with a male-to-female -ratio of 3.3:1. The annual incidence rates increased throughout the study period with an average annual percentage change of +11.4% (95% CI ±7.4%). The highest incidence rates (>200 per 100.000 patient-years) were observed in men aged 80 or more. Altogether 88% of patients were treated conservatively. The proportion of patients treated by mini-invasive surgery significantly increased during study period (0-5.9%, p < 0.001) and was associated with shorter hospitalization (median 6 [interquartile range 4-12] days) than open surgery (median 7 [4.5-13] days) (p < 0.001).

CONCLUSION

The incidence of pleural infections has increased significantly over the previous decades in Finland and appears to be higher than previously reported, particularly in elderly men.

The role of corticosteroids in preventing invasive procedures in patients with parapneumonic effusion in the exudative phase: An observational study

The aim of the study was investigate the effect of corticosteroid use on the need for invasive procedure like tube thoracostomy with underwater seal drainage (TT-UWSD) and Video Assisted Thoracoscopic Surgery (VATS) in adult patients diagnosed with parapneumonic effussion in the exudative phase. A retrospective cohort study was performed in a chest diseases hospital. A total of 65 patients were included in the study. While 30 patients received only medical treatment, 35 patients underwent invasive procedures. Data on characteristics, vital signs, and laboratory parameters were recorded from electronic medical records. Univariate and multivariate logistic regression analyses were performed to identify corticosteroid and other predictors of the need for invasive procedures. The outcomes of the multivariate regression analysis revealed that an longer duration of symptoms (OR = 1.10, 95% CI: 1.01-1.21, P < .033) and the presence of dyspnea (OR = 5.44, 95% CI: 1.26-23.50, P < .023) independently associated with an increased need for invasive procedures, while corticosteroid treatment (OR = 0.15, 95% CI: 0.02-0.81, P < .028) was observed to be associated with a reduced necessity for invasive procedures. Treatment with metilprednisolone, together with the absence of dyspnea and shorter symptom duration may independently decrease the need for invasive procedure in patients with parapneumonic pleural effusion in the exudative phase.

Sonography of the pleura

The CME review presented here is intended to explain the significance of pleural sonography to the interested reader and to provide information on its application. At the beginning of sonography in the 80 s of the 20th centuries, with the possible resolution of the devices at that time, the pleura could only be perceived as a white line. Due to the high impedance differences, the pleura can be delineated particularly well. With the increasing high-resolution devices of more than 10 MHz, even a normal pleura with a thickness of 0.2 mm can be assessed. This article explains the special features of the examination technique with knowledge of the pre-test probability and describes the indications for pleural sonography. Pleural sonography has a high value in emergency and intensive care medicine, preclinical, outpatient and inpatient, in the general practitioner as well as in the specialist practice of pneumologists. The special features in childhood (pediatrics) as well as in geriatrics are presented. The recognition of a pneumothorax even in difficult situations as well as the assessment of pleural effusion are explained. With the high-resolution technology, both the pleura itself and small subpleural consolidations can be assessed and used diagnostically. Both the direct and indirect sonographic signs and accompanying symptoms are described, and the concrete clinical significance of sonography is presented. The significance and criteria of conventional brightness-encoded B-scan, colour Doppler sonography (CDS) with or without spectral analysis of the Doppler signal (SDS) and contrast medium ultrasound (CEUS) are outlined. Elastography and ultrasound-guided interventions are also mentioned. A related further paper deals with the diseases of the lung parenchyma and another paper with the diseases of the thoracic wall, diaphragm and mediastinum.

The clinical features and prognosis of fungal pleural infection: A case series and literature review

Fungal pleural infections are infrequent and insidious, for which there are neither large clinical studies nor targeted guidelines to provide standardized treatment options. We reported 4 cases of fungal pleural infection and reviewed the cases of fungal pleural infections in previous studies to provide a basis for the diagnosis and treatment of fungal pleural infections. There were 2 females and 2 males with a mean age of 58.5 years in our data. The average time from onset to diagnosis was 30.25 days. Risk factors most frequently included pulmonary diseases (n = 4) and malignancy (n = 1). Two patients underwent pleural biopsy through a thoracoscope, and no pathogens were detected. Pleural fluid culture was positive in 2 out of 3 cases. The diagnoses were "possible" (n = 1), "probable" (n = 1), and "proven" (n = 2). All patients received systemic antifungal therapy, and 3 received combined thoracic drainage. The outcomes were cured (n = 1), improved (n = 2) and lost to follow-up (n = 1). We reviewed 12 cases of fungal pleural infection in previous studies. The diagnosis was confirmed via culture in 7 cases and via biopsy in 8 cases. The pathogen was Aspergillus in 7 cases. After a combination of systemic antifungal (n = 12) and local treatment (n = 11), 10 patients improved and 2 patients died. Diagnosis of fungal pleural infection should incorporate risk factors, clinical presentation and fungal evidence, with pleural fluid culture being an important and feasible mean of confirming the diagnosis; and treatment should be based on systemic antifungal therapy supplemented by topical therapy.

An independent prognostic factor in surgical cases of pleural empyema caused by common bacteria is the presence of a fistula

OBJECTIVES

Some surgical cases of pleural empyema lead to death despite multidisciplinary treatment. The purpose of this study was to identify prognostic factors in cases treated surgically for pneumonia-associated pleural effusions and empyema caused by common bacteria.

METHODS

We conducted a retrospective cohort study of 108 surgical patients of empyema who encountered at our hospital between 2011 and 2021. Patients were divided into surviving and non-surviving cases. Factors on admission (age, sex, body mass index, presence of fistula, performance status, pleural fluid culture results, HbA1c, albumin, leukocytes, hemoglobin, body temperature, heart rate, respiratory rate, systolic blood pressure, prognostic nutritional index, neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio and RAPID score) were compared between the two groups.

RESULTS

There were 87 cases of pleural empyema caused by pneumonia due to common bacteria. Variables that differed significantly in univariate analysis between the surviving and non-surviving cases in patients' characteristics on admission were fistula (p value < 0.001, odds ratio 20.000, 95% confidence interval 3.478-115.022), positive pleural fluid culture (0.016, 6.591, 1.190-36.502), body mass index < 18.5 (0.001, 16.857, 1.915-148.349), performance status 0-1 (0.007, 11.778, 1.349-102.858), and hemoglobin (0.024, 1.768, 1.077-2.904). Multivariate analysis showed significant differences in the presence of fistula (p = 0.036, CI 1.174-125.825). The odds ratio was 12.154. The mortality rate was 3.8% for non-fistulous empyema and 44.4% for fistulous empyema. In 6 of 9 cases of fistulous empyema, the fistula could be closed.

CONCLUSION

Fistula was a significant independent prognostic factor for pneumonia-associated pleural effusions and empyema caused by common bacteria.

Targeting the PAI-1 Mechanism with a Small Peptide Increases the Efficacy of Alteplase in a Rabbit Model of Chronic Empyema

The incidence of empyema is increasing and associated with a mortality rate of 20% in patients older than 65 years. Since 30% of patients with advanced empyema have contraindications to surgical treatment, novel, low-dose, pharmacological treatments are needed. A Streptococcus pneumoniae-induced rabbit model of chronic empyema recapitulates the progression, loculation, fibrotic repair, and pleural thickening of human disease. Treatment with single chain (sc) urokinase (scuPA) or tissue type (sctPA) plasminogen activators in doses 1.0-4.0 mg/kg were only partially effective in this model. Docking Site Peptide (DSP; 8.0 mg/kg), which decreased the dose of sctPA for successful fibrinolytic therapy in acute empyema model did not improve efficacy in combination with 2.0 mg/kg scuPA or sctPA. However, a two-fold increase in either sctPA or DSP (4.0 and 8.0 mg/kg or 2.0 and 16.0 mg/kg sctPA and DSP, respectively) resulted in 100% effective outcome. Thus, DSP-based Plasminogen Activator Inhibitor 1-Targeted Fibrinolytic Therapy (PAI-1-TFT) of chronic infectious pleural injury in rabbits increases the efficacy of alteplase rendering ineffective doses of sctPA effective. PAI-1-TFT represents a novel, well-tolerated treatment of empyema that is amenable to clinical introduction. The chronic empyema model recapitulates increased resistance of advanced human empyema to fibrinolytic therapy, thus allowing for studies of muti-injection treatments.

Phenotyping empyema by pleural fluid culture results and macroscopic appearance: an 8-year retrospective study

Background

The clinical impact of phenotyping empyema is poorly described. This study was designed to evaluate clinical characteristics and outcomes based on the two readily available parameters, pleural fluid culture status and macroscopic fluid appearance.

Methods

A retrospective study was conducted on patients with empyema hospitalised between 2013 and 2020. Empyema was classified into culture-positive empyema (CPE) or culture-negative empyema (CNE) and pus-appearing empyema (PAE) or non-pus-appearing empyema (non-PAE) based on the pleural fluid culture status and macroscopic fluid appearance, respectively.

Results

Altogether, 212 patients had confirmed empyema (CPE: n=188, CNE: n=24; PAE: n=118, non-PAE: n=94). The cohort was predominantly male (n=163, 76.9%) with a mean age of 65.0±13.6 years. Most patients (n=180, 84.9%) had at least one comorbidity. Patients with CPE had higher rates of in-hospital mortality (19.1% versus 0.0%, p=0.017) and 90-day mortality (18.6% versus 0.0%, p=0.017) and more extrapulmonary sources of infection (29.8% versus 8.3%, p=0.026) when compared with patients with CNE. No significant difference in mortality rate was found between PAE and non-PAE during the in-hospital stay and at 30 days and 90 days. Patients with PAE had less extrapulmonary sources of infection (20.3% versus 36.2%, p=0.010) and more anaerobic infection (40.9% versus 24.5%, p=0.017) than those with non-PAE. The median RAPID (renal, age, purulence, infection source, and dietary factors) scores were higher in the CPE and non-PAE groups. After adjusting for covariates, culture positivity was not independently associated with mortality on multivariable analysis.

Conclusion

Empyema is a heterogeneous disease with different clinical characteristics. Phenotyping empyema into different subclasses based on pleural fluid microbiological results and macroscopic fluid appearance provides insight into the underlying bacteriology, source of infection and subsequent clinical outcomes.

Diagnosis and Treatment of Pleural Effusion. Recommendations of the Spanish Society of Pulmonology and Thoracic Surgery. Update 2022

Pleural effusion (PE) is a common yet complex disease that requires specialized, multidisciplinary management. Recent advances, novel diagnostic techniques, and innovative patient-centered therapeutic proposals have prompted an update of the current guidelines. This document provides recommendations and protocols based on a critical review of the literature on the epidemiology, etiology, diagnosis, prognosis, and new therapeutic options in PE, and addresses some cost-effectiveness issues related to the main types of PE.

Nontuberculous mycobacteria infections of the pleura: A systematic review

BACKGROUND

Nontuberculous mycobacterial (NTM) pleuritis is an uncommon manifestation of NTM infection. Case reports and small case series have shown a variable clinical course and high mortality rates.

OBJECTIVE

To describe patients' characteristics, clinical presentation and outcomes of NTM pleural infections.

METHODS

A systematic review of cases of NTM pleural infections published in PubMed-indexed journals from 1980 to 2021.

RESULTS

A total of 206 cases of NTM pleural infections were found and analyzed. Fifty-eight percent of cases were males. The mean age was 57.5 yrs (range 9-87 yrs). Forty-three percent of patients were immunosuppressed, and 43% had a chronic lung disease; thirty-two percent had neither risk factor. In addition to the pleural infection, 67% of cases had a concurrent pulmonary NTM infection, and in 18 cases there was another extrapulmonary site of NTM infection. In 29% of cases the pleural infection was the sole manifestation of NTM disease. The most common isolated mycobacterium was Mycobacterium avium complex (65%). Fifty-three percent and 26% of patients required pleural effusion drainage and a surgical intervention, respectively, to treat the infection, in addition to anti-NTM chemotherapy. Forty percent of patients developed pneumothorax, 16% suffered from empyema, and 16.5% had broncho-pleural fistula. The reported mortality rate was 24%.

CONCLUSION

NTM pleural infections may arise in immunocompetent and immunosuppressed patients, with or without chronic lung disease or concurrent NTM pulmonary infection. These infections carry a poor prognosis and a high risk of complications requiring surgical interventions in addition to anti-NTM chemotherapy.

Pyopneumothorax Caused by Trichomonas tenax and Porphyromonas endodontalis Coinfection in a Patient with Previous Cerebral Infarction: A Case Report and Literature Review

Background

Even with the advent of NGS and PCR diagnostic tools, cases of chest infections caused by Trichomonas are still very rare. Such pathogens are less likely to be considered by clinicians. These cases frequently involve the pleura and lead to pneumothorax, hydropneumothorax, or pyopneumothorax, making the disease severe.

Case Presentation

A 69-year-old man diagnosed with cerebral infarction a year ago sought medical attention for right-sided pyopneumothorax and respiratory failure. The pathogen found in the pleural fluid was highly suspected to be Trichomonas tenax (T. tenax). Pleural fluid mNGS confirmed T. tenax and Porphyromonas endodontalis coinfection. Metronidazole combined with piperacillin tazobactam was administered to counteract infection. Simultaneously, closed chest drainage and thoracoscopic release of pleural adhesions were performed. The patient was cured, discharged from the hospital, and was in good condition after six months of follow-up.

Conclusion

When chest infections occur in patients with poor oral hygiene and underlying diseases that may lead to aspiration, the identification of Trichomonas infection should be noted. Early confirmation of the diagnosis often requires mNGS and PCR. Metronidazole is essentially effective against Trichomonas, and medical thoracoscopy can be used to manage pleural conditions if necessary.

Assessment of Pleural Effusion by Means of Imaging Modalities

Pleural effusion is the fluid collection in the pleural cavity between the parietal and visceral pleura. It is caused by parenchymal diseases such as inflammatory disorders or infection. Pleural effusion can be diagnosed using imaging modalities such as X-ray, computed tomography (CT) scan, ultrasound, and magnetic resonance imaging (MRI).

MRI is rarely performed to investigate pleural effusion due to motion artifacts and has a poor spatial resolution. Benign and malignant pleural effusion can be diagnosed using an X-ray, CT scan, or ultrasound. Pleural effusion volume can be measured by using ultrasound. This article reviews the feasibility of investigating pleural effusion and fluid drainage in medical imaging and compares to find the best modality for its diagnosis.

Description: This article reports the possible options to detect pleural effusion in medical imaging and compares them to find the best modality for its diagnosis.

Risk of Pleural Empyema in Adult Patients With Asthma: A Nationwide Retrospective Cohort Study

Background

Respiratory system infections commonly occur among individuals with asthma. However, whether asthma patients have a higher risk of pleural empyema development remains unclear.

Methods

This is a retrospective cohort study based on data from the National Health Insurance Research Database of Taiwan. The asthma cohort consisted of 48,360 newly diagnosed adult individuals from 2000 to 2012. The comparison cohort consisted of the same number of adults who did not have asthma and was matched for age, gender, comorbidity, and the year of diagnosis. The development of pleural empyema was followed up to 2013.

Results

Pleural empyema incidence was 2.03-fold higher in the asthma cohort compared to the comparison cohort (8.65 vs. 4.25 per 10,000 person-years), with an adjusted hazard ratio (HR) of 2.12 [95% confidence interval (CI) = 1.76–2.56]. Stratified analyses by age, gender, comorbidity, and corticosteroid use revealed that the crude and adjusted HRs of pleural empyema associated with asthma were all significant. Among patients with asthma, the risk of pleural empyema elevated with increased frequency of annual asthma-related emergency room visits and hospital admissions (≥1 vs. &lt;1, aHR = 8.07, 95% CI = 4.31–15.1 and aHR = 9.31, 95% CI = 5.56–15.6).

Conclusion

An increased risk of pleural empyema occurrence was observed in adult patients with asthma than those without asthma. Furthermore, the risk of pleural empyema may increase with poor control of asthma.

Inflammation of the Pleural Cavity: A Review on Pathogenesis, Diagnosis and Implications in Tumor Pathophysiology

Pleural effusions are a common respiratory condition with many etiologies. Nonmalignant etiologies explain most pleural effusions and despite being nonmalignant, they can be associated with poor survival; thus, it is important to understand their pathophysiology. Furthermore, diagnosing a benign pleural pathology always harbors the uncertainty of a false-negative diagnosis for physicians and pathologists, especially for the group of non-specific pleuritis. This review aims to present the role of the inflammation in the development of benign pleural effusions, with a special interest in their pathophysiology and their association with malignancy.

From Bedside to the Bench—A Call for Novel Approaches to Prognostic Evaluation and Treatment of Empyema

Empyema, a severe complication of pneumonia, trauma, and surgery is characterized by fibrinopurulent effusions and loculations that can result in lung restriction and resistance to drainage. For decades, efforts have been focused on finding a universal treatment that could be applied to all patients with practice recommendations varying between intrapleural fibrinolytic therapy (IPFT) and surgical drainage. However, despite medical advances, the incidence of empyema has increased, suggesting a gap in our understanding of the pathophysiology of this disease and insufficient crosstalk between clinical practice and preclinical research, which slows the development of innovative, personalized therapies. The recent trend towards less invasive treatments in advanced stage empyema opens new opportunities for pharmacological interventions. Its remarkable efficacy in pediatric empyema makes IPFT the first line treatment. Unfortunately, treatment approaches used in pediatrics cannot be extrapolated to empyema in adults, where there is a high level of failure in IPFT when treating advanced stage disease. The risk of bleeding complications and lack of effective low dose IPFT for patients with contraindications to surgery (up to 30%) promote a debate regarding the choice of fibrinolysin, its dosage and schedule. These challenges, which together with a lack of point of care diagnostics to personalize treatment of empyema, contribute to high (up to 20%) mortality in empyema in adults and should be addressed preclinically using validated animal models. Modern preclinical studies are delivering innovative solutions for evaluation and treatment of empyema in clinical practice: low dose, targeted treatments, novel biomarkers to predict IPFT success or failure, novel delivery methods such as encapsulating fibrinolysin in echogenic liposomal carriers to increase the half-life of plasminogen activator. Translational research focused on understanding the pathophysiological mechanisms that control 1) the transition from acute to advanced-stage, chronic empyema, and 2) differences in outcomes of IPFT between pediatric and adult patients, will identify new molecular targets in empyema. We believe that seamless bidirectional communication between those working at the bedside and the bench would result in novel personalized approaches to improve pharmacological treatment outcomes, thus widening the window for use of IPFT in adult patients with advanced stage empyema.

An international survey on the use of intrapleural tissue plasminogen activator/DNase therapy for pleural infection

Introduction

Intrapleural tissue plasminogen activator (tPA) combined with human recombinant DNase (DNase) could be an effective alternative to surgery in managing pleural infection, as demonstrated in the Multi-centre Intrapleural Sepsis Trial (MIST)-2. However, the optimal delivery regimen is still unknown. The aim of this survey was to identify the current practice of tPA/DNase use by physicians with published interests in pleural infection, and their opinions on dose de-escalation of tPA/DNase therapy.

Methods

Potential participants were identified using four search strategies. Only practising physicians who were managing patients with pleural infections and either actively involved in pleural research and publications, or were members of relevant pleural disease guideline panels at the time of survey were included.

Results

An invitation email with the questionnaire was sent to 102 participants, of whom 49 (48%) responded. Most respondents (90%, n=44) have used tPA/DNase to manage pleural infection, but the dosing and delivery regimens employed varied. Many (86%, 38 out of 44) respondents have used 10 mg tPA, while 73% (n=32), 16% (n=7) and 9% (n=4) have used 5 mg, 2.5 mg and 1 mg doses, respectively. Most respondents instilled tPA/DNase concurrently (61%, n=27) and routinely administered six doses of tPA/DNase (52%, n=23) twice daily (82%, n=36). Respondents would consider using a lower starting dose of tPA (with the possibility of escalation if clinically needed) if a median 80% (interquartile range 50–80%) of patients could be successfully treated at that dose.

Conclusion

This survey observed a large variation in the current treatment protocol of intrapleural tPA/DNase therapy worldwide and the need for more data on this subject.

This international survey observed a large variation in the delivery of tPA/DNase therapy for pleural infection. Respondents were open to the concept of starting with a lower (<10 mg) dose of tPA (with the possibility of escalation) if evidence accumulates.https://bit.ly/2ZfPRrL

Optimizing the management of complicated pleural effusion: From intrapleural agents to surgery

Pleural effusion is a frequent complication of acute pulmonary infection and can affect its morbidity and mortality. The possible evolution of a parapneumonic pleural effusion includes 3 stages: exudative (simple accumulation of pleural fluid), fibropurulent (bacterial invasion of the pleural cavity), and organized stage (scar tissue formation). Such a progression is favored by inadequate treatment or imbalance between microbial virulence and immune defenses. Biochemical features of a fibrinopurulent collection include a low pH (<7.20), low glucose level (<60 mg/dl), and high lactate dehydrogenase (LDH). A parapneumonic effusion in the fibropurulent stage is usually defined "complicated" since antibiotic therapy alone is not enough for its resolution and an invasive procedure (pleural drainage or surgery) is required. Chest ultrasound is one of the most useful imaging tests to assess the presence of a complicated pleural effusion. Simple parapneumonic effusions are usually anechoic, whereas complicated effusions often have a complex appearance (non-anechoic, loculated, or septated). When simple chest tube placement fails and/or patients are not suitable for more invasive techniques (i.e. surgery), intra-pleural instillation of fibrinolytic/enzymatic therapy (IPET) might represent a valuable treatment option to obtain the lysis of fibrin septa. IPET can be used as either initial or subsequent therapy. Further studies are ongoing or are required to help fill some gaps on the optimal management of parapneumonic pleural effusion. These include the duration of antibiotic therapy, the risk/benefit ratio of medical thoracoscopy and surgery, and new intrapleural treatments such as antibiotic-eluting chest tubes and pleural irrigation with antiseptic agents.

Recent Insights into the Management of Pleural Infection

Pleural infection in adults has considerable morbidity and continues to be a life-threatening condition. The term “pleural infection” encompasses complicated parapneumonic effusions and primary pleural infections, and includes but is not limited to empyema, which refers to collection of pus in the pleural cavity. The incidence of pleural infection in adults has been continuously increasing over the past two decades, particularly in older adults, and most of such patients have comorbidities. Management of pleural infection requires prolonged duration of hospitalization (average 14 days). There are recognized differences in microbial etiology of pleural infection depending on whether the infection was acquired in the community or in a health-care setting. Anaerobic bacteria are acknowledged as a major cause of pleural infection, and thus anaerobic coverage in antibiotic regimens for pleural infection is mandatory. The key components of managing pleural infection are appropriate antimicrobial therapy and chest-tube drainage. In patients who fail medical therapy by manifesting persistent sepsis despite standard measures, surgical intervention to clear the infected space or intrapleural fibrinolytic therapy (in poor surgical candidates) are recommended. Recent studies have explored the role of early intrapleural fibrinolytics or first-line surgery, but due to considerable costs of such interventions and the lack of convincing evidence of improved outcomes with early use, early intervention cannot be recommended, and further evidence is awaited from ongoing studies. Other areas of research include the role of routine molecular testing of infected pleural fluid in improving the rate of identification of causative organisms. Other research topics include the benefit of such interventions as medical thoracoscopy, high-volume pleural irrigation with saline/antiseptic solution, and repeated thoracentesis (as opposed to chest-tube drainage) in reducing morbidity and improving outcomes of pleural infection. This review summarizes current knowledge and practice in managing pleural infection and future research directions.

Management of Pleural Infection

Pleural infection is a millennia-spanning condition that has proved challenging to treat over many years. Fourteen percent of cases of pneumonia are reported to present with a pleural effusion on chest X-ray (CXR), which rises to 44% on ultrasound but many will resolve with prompt antibiotic therapy. To guide treatment, parapneumonic effusions have been separated into distinct categories according to their biochemical, microbiological and radiological characteristics. There is wide variation in causative organisms according to geographical location and healthcare setting. Positive cultures are only obtained in 56% of cases; therefore, empirical antibiotics should provide Gram-positive, Gram-negative and anaerobic cover whilst providing adequate pleural penetrance. With the advent of next-generation sequencing techniques, yields are expected to improve. Complicated parapneumonic effusions and empyema necessitate prompt tube thoracostomy. It is reported that 16-27% treated in this way will fail on this therapy and require some form of escalation. The now seminal Multi-centre Intrapleural Sepsis Trials (MIST) demonstrated the use of combination fibrinolysin and DNase as more effective in the treatment of empyema compared to either agent alone or placebo, and success rates of 90% are reported with this technique. The focus is now on dose adjustments according to the patient's specific 'fibrinolytic potential', in order to deliver personalised therapy. Surgery has remained a cornerstone in the management of pleural infection and is certainly required in late-stage manifestations of the disease. However, its role in early-stage disease and optimal patient selection is being re-explored. A number of adjunct and exploratory therapies are also discussed in this review, including the use of local anaesthetic thoracoscopy, indwelling pleural catheters, intrapleural antibiotics, pleural irrigation and steroid therapy.

Medical thoracoscopy treatment for pleural infections: a systematic review and meta-analysis

Background

Complicated parapneumonic effusions and empyema represent advanced stages of pleural infections and are characterized by a high mortality. Medical thoracoscopy is a safe and minimally invasive endoscopic technique prescribed to treat severe pleural infections. However, only a few studies evaluated its success rate. A systematic review of observational studies was performed to assess the efficacy of medical thoracoscopy in patients with complicated parapneumonic effusions and empyema, as well as its predictive factors.

Methods

A search of the scientific evidence was carried out using PubMed, EMBASE, and Cochrane Central Register of Controlled Trials. Articles describing observational studies on medical thoracoscopy in patients with parapneumonic effusions and empyema were selected.

Results

Eight studies met the inclusion criteria. The pooled treatment success rate of thoracoscopy was 85% (95% CI 80.0–90.0%; I²: 61.8%) when used as first-line intervention or after failure of chest tube. The pooled complication rate was 9.0% (95% CI 6.0–14.0%; I²: 58.8%). A pooled difference of treatment success of 9.0% (95% CI 1.0–18.0%) was found when post-thoracoscopy intra-pleural fibrinolysis was prescribed. Pooled success rate was higher in cases with pleural fluid culture negativity (pooled difference: 14.0%; 95% CI 4.0–24.0%).

Conclusions

Medical thoracoscopy is effective and safe when prescribed for complicated parapneumonic effusions and empyema. Bacteriological negativity of pleural effusion specimens and administration of adjuvant intra-pleural fibrinolysis after the procedure are associated with a higher success rate.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01492-9.

Medical Thoracoscopy for the Management of Exudative Pleural Effusion: A Retrospective Study

Objective

The aim of this study was to evaluate the efficacy of medical thoracoscopy in the diagnosis and treatment of exudative pleural effusion.

Methods

A total of 82 patients with exudative pleural effusion underwent medical thoracoscopy under local anesthesia and mild sedation. The clinical characteristics, pleural fluid routine and biochemical tests, pleural biopsy, and outcomes were retrospectively evaluated.

Results

Among 82 patients, the color and transparency of pleural fluid and the levels of white blood cells (WBC), lactate dehydrogenase (LDH), neutrophil proportion, lymphocyte proportion, adenosine deaminase (ADA), and glucose were different among tuberculosis (TB), malignant (M), acute and chronic inflammation (ACI), and purulent (P) cases. Furthermore, 70% of M cases had a low positive rate of exfoliated cells in the sputum and pleural fluid, and more than 90% of TB cases had low positive rates of anti-tuberculosis antibodies and acid-fast bacilli in the sputum and pleural fluid. Pleural biopsy showed that 11% of cases were M, 74.4% were TB, 11% were ACI, and 3.6% were P. Medical thoracoscopy showed that 66.7% of ACI cases had pleural adhesions, 34.4% of TB cases had moderate and 34.4% of TB cases had severe pleural adhesions, 100% of M and TB cases had pleural surface nodules and 77.8% of ACI cases had pleural surface nodules, 49.2% of TB cases showed encapsulated pleural effusion, and 33.3% of M cases showed encapsulated pleural effusion.

Conclusion

Medical thoracoscopy has high feasibility and accuracy in the diagnosis and treatment of exudative pleural effusion.

Diagnostic Value of C-Reactive Protein in Discrimination between Uncomplicated and Complicated Parapneumonic Effusion

Objectives: The role of serum C-reactive protein (CRPs) and pleural fluid CRP (CRPpf) in discriminating uncomplicated parapneumonic effusion (UCPPE) from complicated parapneumonic effusion (CPPE) is yet to be validated since most of the previous studies were on small cohorts and with variable results. The role of CRPs and CRPpf gradient (CRPg) and of their ratio (CRPr) in this discrimination has not been previously reported. The study aims to assess the diagnostic efficacy of CRPs, CRPpf, CRPr, and CRPg in discriminating UCPPE from CPPE in a relatively large cohort. Methods: The study population included 146 patients with PPE, 86 with UCPPE and 60 with CPPE. Levels of CRPs and CRPpf were measured, and the CRPg and CRPr were calculated. The values are presented as mean ± SD. Results: Mean levels of CRPs, CRPpf, CRPg, and CRPr of the UCPPE group were 145.3 ± 67.6 mg/L, 58.5 ± 38.5 mg/L, 86.8 ± 37.3 mg/L, and 0.39 ± 0.11, respectively, and for the CPPE group were 302.2 ± 75.6 mg/L, 112 ± 65 mg/L, 188.3 ± 62.3 mg/L, and 0.36 ± 0.19, respectively. Levels of CRPs, CRPpf, and CRPg were significantly higher in the CPPE than in the UCPPE group (p < 0.0001). No significant difference was found between the two groups for levels of CRPr (p = 0.26). The best cut-off value calculated by the receiver operating characteristic (ROC) analysis for discriminating UCPPE from CPPE was for CRPs, 211.5 mg/L with area under the curve (AUC) = 94% and p < 0.0001, for CRPpf, 90.5 mg/L with AUC = 76.3% and p < 0.0001, and for CRPg, 142 mg/L with AUC = 91% and p < 0.0001. Conclusions: CRPs, CRPpf, and CRPg are strong markers for discrimination between UCPPE and CPPE, while CRPr has no role in this discrimination.

Rheumatoid arthritis increases the risk of pleural empyema

Background

Rheumatoid arthritis (RA) can lead to various pulmonary manifestations. Evidence shows the possible association between RA and pleural empyema.

Methods

We conducted a retrospective cohort study to investigate the risk of pleural empyema in patients with RA. The RA group (n = 29,061) included newly diagnosed adult patients between 2000 and 2012. The comparison group (n = 1,16,244) included individuals without RA at a 1:4 ratio of frequency matched by age, gender, and diagnosis year. The occurrence of pleural empyema was monitored until the end of 2013.

Results

Patients with RA had a higher risk of developing pleural empyema than those without RA (23.6 vs 1.82 per 10,000 person-years, adjusted hazard ratio = 11.0, 95% confidence interval [CI] = 8.90–13.5). Furthermore, intensive care unit admission rates of pleural empyema were 37.7% in the RA group and 37.2% in the comparison group (adjusted odds ratio [OR] = 1.02, 95% CI = 0.66−1.57). The 30-day mortality rates of pleural empyema were 11.2% in the RA group and 10.9% in the comparison group (adjusted OR = 1.01, 95% CI = 0.51−1.88).

Conclusion

Patients with RA are at a greater risk of developing pleural empyema than those without RA.

The Use of a Novel Quantitative Marker of Echogenicity of Pleural Fluid in Parapneumonic Pleural Effusions

Background

Thoracic ultrasound is an essential tool in the daily clinical care of pleural effusions and especially parapneumonic pleural effusions (PPEs), in terms of diagnosis, management, and follow-up. Hypoechogenicity index (HI) is a quantitative marker of pleural fluid echogenicity. We aimed to examine associations of HI with pleural inflammation in patients with PPE.

Methods

All patients included underwent a thoracic ultrasound with HI determination at the first day of their admission for a PPE. Thoracentesis was performed in all patients. Demographics, laboratory measurements, and clinical data were collected prospectively and recorded in all subjects.

Results

Twenty-four patients with PPE were included in the study. HI was statistically significantly correlated with intensity of inflammation as suggested by pleural fluid LDH (p < 0.001, r = −0.831), pleural fluid glucose (p=0.022, r = 0.474), and pleural fluid pH (p < 0.001, r = 0.811). HI was correlated with ADA levels (p=0.005, r = −0.552). We observed a statistically significant correlation of HI with pleural fluid total cell number (p < 0.001, r = −0.657) and polymorphonuclears percentage (p=0.02, r = −0.590), as well as days to afebrile (p=0.046, r = −0.411), duration of chest tube placement (p < 0.001, r = −0.806), and days of hospitalization (p=0.013, r = −0.501). Discussion. HI presents a fast, easily applicable, objective, and quantitative marker of pleural inflammation that reliably reflects the intensity of pleural inflammation and could potentially guide therapeutic management of PPE.

Pleural effusions and pneumothorax: Beyond simple plumbing: Expert opinions on knowledge gaps and essential next steps

Pleural diseases affect millions of people worldwide. Pleural infection, malignant pleural diseases and pneumothorax are common clinical challenges. A large number of recent clinical trials have provided an evidence-based platform to evaluate conventional and novel methods to drain pleural effusions/air which reduce morbidity and unnecessary interventions. These successes have generated significant enthusiasm and raised the profile of pleural medicine as a new subspecialty. The ultimate goal of pleural research is to prevent/stop development of pleural effusions/pneumothorax. Current research studies mainly focus on the technical aspects of pleural drainage. Significant knowledge gaps exist in many aspects such as understanding of the pathobiology of the underlying pleural diseases, pharmacokinetics of pleural drug delivery, etc. Answers to these important questions are needed to move the field forward. This article collates opinions of leading experts in the field in highlighting major knowledge gaps in common pleural diseases to provoke thinking beyond pleural drainage. Recognizing the key barriers will help prioritize future research in the quest to ultimately cure (rather than just drain) these pleural conditions.

Factors associated with variations in the rate of referrals and microbiology of pleural infection

OBJECTIVES

Invasive pneumococcal disease is seasonal and associated with influenza, but the same is uncertain for pleural infection. We set out to investigate whether pleural infection referrals similarly correlate with the seasonal variation in influenza burden and whether the microbiologic etiology varies according to certain factors.

METHODS

Cases of pleural infection were retrieved from the database of a Pleural Unit in a tertiary hospital in the UK. The rate of referrals for pleural infection was compared to contemporary national rates of influenza hospitalizations and primary care presentation with influenza like illnesses.

RESULTS

Between August 2015 and December 2019, 157 cases of pleural infection were diagnosed. The monthly rate of referrals with pleural infections was 3.8 cases/month, but this varied between months [range 0-6 cases]. No clear increase in pleural infection referrals coinciding or falling after peak influenza diagnosis was observed. However, the rate of infection referrals correlated positively with the overall monthly volume of pleural referrals (β 0.035, p = 0.004). Gram negative bacteria seemed more common during the hotter months, in hospital-acquired infections and in younger adults. Young adults were more commonly infected with pneumococci than older adults, who were more vulnerable to anaerobic infections.

CONCLUSION

Direct association between the rate of pleural infection cases and influenza activity was not identified. Pleural infection microbiology appears to differ according to age and environmental temperatures.

Depression is associated with subsequent risk of pleural empyema

Background:

Respiratory system infections are prevalent in patients with depression. However, it remains unclear if patients with depression are at an increased risk of developing pleural empyema.

Methods:

We conducted a retrospective cohort study using data from the National Health Insurance Research Database of Taiwan. The depression group included 42,283 newly diagnosed patients between 2000 and 2012. The comparison group included the same number of individuals without depression, frequency matched for age, sex, comorbidities, and the year of diagnosis. The occurrence of pleural empyema was monitored until the end of 2013.

Results:

The overall incidence of pleural empyema was 1.32-fold higher in the depression group than in the comparison group (3.94 versus 2.97 per 10,000 person-years), with an adjusted hazard ratio of 1.33 (95% confidence interval, 1.27−1.40). Stratified analyses by age, sex, and comorbidity revealed that the crude and adjusted hazard ratios of pleural empyema associated with depression were significant in all subgroups. The 30-day mortality for pleural empyema was higher, but not significantly, in the depression group compared to the comparison group (10.7% versus 6.4%, adjusted odds ratio = 2.23, 95% confidence interval, 0.77−6.49).

Conclusion:

An association between depression and the development of pleural empyema may exist; however, more evidence is required to support this association.

The reviews of this paper are available via the supplemental material section.

Concurrent fusobacterial pyogenic liver abscess and empyema

We present a very rare case of concurrent empyema and liver abscess caused by Fusobacterium. Our patient presented with 3-month history of subtle abdominal discomfort and cough leading to eventually presenting with marked chest pain, dyspnoea and septic shock. CT revealed a liver abscess and large right-sided pleural effusion. Drainage of the pleural effusion yielded gross pus with the growth of Fusobacterium varium, while drainage of the liver abscess yielded Fusobacterium nucleatum The patient responded to drainage and antibiotic therapy with resolution of symptoms and decrease in the size of empyema and abscess on follow-up imaging. We also include a review if literature of related fusobacterial infections.

The microbiology of pleural infection in adults: a systematic review

BACKGROUND AND OBJECTIVES

Pleural infection is a major cause of morbidity and mortality among adults. Identification of the offending organism is key to appropriate antimicrobial therapy. It is not known whether the microbiological pattern of pleural infection is variable temporally or geographically. This systematic review aimed to investigate available literature to understand the worldwide pattern of microbiology and the factors that might affect such pattern.

DATA SOURCES AND ELIGIBILITY CRITERIA

Ovid MEDLINE and Embase were searched between 2000 and 2018 for publications that reported on the microbiology of pleural infection in adults. Both observational and interventional studies were included. Studies were excluded if the main focus of the report was paediatric population, tuberculous empyema or post-operative empyema.

STUDY APPRAISAL AND SYNTHESIS METHODS

Studies of ≥20 patients with clear reporting of microbial isolates were included. The numbers of isolates of each specific organism/group were collated from the included studies. Besides the overall presentation of data, subgroup analyses by geographical distribution, infection setting (community versus hospital) and time of the report were performed.

RESULTS

From 20 980 reports returned by the initial search, 75 articles reporting on 10 241 patients were included in the data synthesis. The most common organism reported worldwide was Staphylococcus aureus. Geographically, pneumococci and viridans streptococci were the most commonly reported isolates from tropical and temperate regions, respectively. The microbiological pattern was considerably different between community- and hospital-acquired infections, where more Gram-negative and drug-resistant isolates were reported in the hospital-acquired infections. The main limitations of this systematic review were the heterogeneity in the method of reporting of certain bacteria and the predominance of reports from Europe and South East Asia.

CONCLUSIONS

In pleural infection, the geographical location and the setting of infection have considerable bearing on the expected causative organisms. This should be reflected in the choice of empirical antimicrobial treatment.

A systematic review of comorbidities and outcomes of adult patients with pleural infection

Background

Pleural infection remains an important cause of mortality. This study aimed to investigate worldwide patterns of pre-existing comorbidities and clinical outcomes of patients with pleural infection.

Methods

Studies reporting on adults with pleural infection between 2000 and 2017 were identified from a search of Embase and MEDLINE. Articles reporting exclusively on tuberculous, fungal or post-pneumonectomy infection were excluded. Two reviewers assessed 20 980 records for eligibility.

Results

211 studies met the inclusion criteria. 134 articles (227 898 patients, mean age 52.8 years) reported comorbidity and/or outcome data. The majority of studies were retrospective observational cohorts (n=104, 78%) and the most common region of reporting was East Asia (n=33, 24%) followed by North America (n=27, 20%). 85 articles (50 756 patients) reported comorbidity. The median (interquartile range (IQR)) percentage prevalence of any comorbidity was 72% (58–83%), with respiratory illness (20%, 16–32%) and cardiac illness (19%, 15–27%) most commonly reported. 125 papers (192 298 patients) reported outcome data. The median (IQR) length of stay was 19 days (13–27 days) and median in-hospital or 30-day mortality was 4% (IQR 1–11%). In regions with high-income economies (n=100, 74%) patients were older (mean 56.5 versus 42.5 years, p<0.0001), but there were no significant differences in prevalence of pre-existing comorbidity nor in length of hospital stay or mortality.

Conclusion

Patients with pleural infection have high levels of comorbidity and long hospital stays. Most reported data are from high-income economy settings. Data from lower-income regions is needed to better understand regional trends and enable optimal resource provision going forward.

In pleural infection, patients from higher-income countries tend to be older with more comorbidities and are more likely to be referred for fibrinolytic treatment in comparison to patients from lower-income countrieshttp://bit.ly/2K2M5HL

Pleural infection: a closer look at the etiopathogenesis, microbiology and role of antibiotics

INTRODUCTION

Pleural infection is a condition that continues to pose a significant challenge to respiratory physicians. We hypothesize that the main barriers to progress include limited understanding of the etiopathogenesis, microbiology,and role of antibiotics in the pleural space. Areas covered: PubMed was searched for articles related to adult pleural infection using the terms 'pleural infection', 'empyema' and 'parapneumonic'. The search focused on relevant literature within the last 10 years, with any older citations used only to display context or lack of progress. Tuberculous pleural infection was excluded. We chose to give specific attention to the etiopathogenesis of pleural infection, including recent advances in diagnostics and biomarkers. We discuss our understanding of the pleural microbiome and rationalize the current use of antibiotics in treating this condition. Expert commentary: Understanding of key events in the development of this condition remains limited. The microbiology is unique compared to the lung, and highly variable. Higher culture yields from pleural biopsy may add new insights into the etiopathogenesis. There is little evidence into achievable effective antibiotic concentration within the pleura. Research into issues including the relevance of biofilm formation and significance of pleural thickening is necessary for treatment progress.