Complicated parapneumonic effusion and empyema thoracis: Microbiologic and therapeutic aspects

Diagnosis of pleural empyema/parapneumonic effusion by next-generation sequencing

BACKGROUND

Although a microbiological diagnosis of pleural infection is clinically important, it is often complicated by prior antibiotic treatment and/or difficulties with culturing some bacterial species. Therefore, we aimed to identify probable causative bacteria in pleural empyema/parapneumonic effusions by combining 16S ribosomal RNA (rRNA) gene amplification and next-generation sequencing (NGS).

METHODS

Pleural fluids were collected from 19 patients with infectious effusions and nine patients with non-infectious malignant effusions. We analysed DNA extracted from the pleural fluid supernatant by NGS using the Genome Search Toolkit and GenomeSync database, either directly or after PCR amplification of the 16S rRNA gene. Infectious and non-infectious effusions were distinguished by semi-quantitative PCR of the 16S rRNA gene.

RESULTS

Only 8 (42%) effusions were culture-positive, however, NGS of the 16S rRNA gene amplicon identified 14 anaerobes and 7 aerobes/facultative anaerobes in all patients, including Streptococcus sp. (n = 6), Fusobacterium sp. (n = 5), Porphyromonas sp. (n = 5), and Prevotella sp. (n = 4), accounting for >10% of the total genomes. The culture and NGS results were discordant for 3 out of 8 patients, all of whom had previously been treated with antibiotics. Total (2^ΔCT value in semi-quantitative PCR of the 16S rRNA gene) and specific (total bacterial load multiplied by the proportion of primary bacteria in NGS) bacterial loads could efficiently distinguish empyema/parapneumonic effusion from non-infectious effusion.

CONCLUSION

Combining NGS with semi-quantitative PCR can facilitate the diagnosis of pleural empyema/parapneumonic effusion and its causal bacteria.

Preoperative undernutrition predicts postoperative complications of acute empyema

INTRODUCTION

Surgery for acute empyema is associated with postoperative complications and relapse. Establishing a predictor for postoperative complications may improve prognosis.

OBJECTIVES

To demonstrate undernutrition as a predictor of complications after surgery for acute empyema.

METHODS

We retrospectively analyzed 52 consecutive patients who underwent surgery for acute empyema from 2004 to 2019 and validated the correlation of undernutrition with serum albumin level, patient characteristics, hospital stay, and postoperative complications.

RESULTS

The median preoperative serum albumin level was 2.4 g/dL (range: 1.1-3.4). The levels in all patients were lower than the standard value (3.5 g/dL). Patients were divided into two groups based on the median serum albumin levels: the low serum albumin level group (group L, n = 28) and the high serum albumin level group (group H, n = 24). Group L patients were significantly older (64.5 vs 52.9 years, P = .002), had lower median body mass index (21.0 vs 24.2, P = .008), and significantly had Streptococcus anginosus group as the causative bacteria (50% vs 21%, P = .044). Their hospitalization duration was significantly longer (28.1 vs 14.8 days, P < .001), and postoperative complications were significant or tended to be more frequent (all incidence; 11 (39%) vs 2 (8%), P = .012, respiratory-related; 7 (25%) vs 1 (4%), P = .056) in group L. Further analyses revealed that other undernutrition indicators also correlated with postoperative complications.

CONCLUSIONS

Preoperative serum albumin level is a valid predictor of complications after surgery for acute empyema. Preoperative nutrition management for empyema patients may reduce the occurrence of postoperative complications.

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

Features of Parapneumonic Effusions

Introduction: Parapneumonic effusions, as a complication of community-acquired pneumonia (CAP), usually have a good course, but they sometimes progress into complicated parapneumonic effusion (CPPE) and empyema, thus becoming a significant clinical problem.

Aim: To review clinical and radiological features, as well as diagnostic and therapeutic options in parapneumonic effusions.

Material and methods: The analysis included 94 patients with parapneumonic effusion hospitalized at the University Infectious Diseases Clinic in Skopje during a 4 year period. Out of 755 patients with CAP, 175 (23.18%), had parapneumonic effusion. Thoracentesis was performed in 94 (53.71%) patients, 50 patients were with uncomplicated parapneumonic effusions (UCPPE) and 44 with complicated parapneumonic effusions (CPPE).

Results: More patients (59.57%) were male; the average age was 53.82±17.5 years. The most common symptoms included: fever (91; 96.81%), cough (80; 85.11%), pleuritic chest pain (68; 72.34%), dyspnea (65; 69.15%). Alcoholism was the most common comorbidity registered in 12 (12.77%) patients. Macroscopically, effusion was yellow and clear in most cases (36; 38.29%). Localization of pleural effusion was often in the left costophrenic angle (53; 56.38%) and ultrasonographic non-septated complex. Between the two groups of effusions there was a significant difference between the ERS, WBC and CRP in serum and CRP in pleural fluid. Statistical difference existed in terms of days of hospitalization with a longer hospital stay for patients with CPPE (p <0.0001).

Conclusion: Patients with parapneumonic effusion have the symptoms of acute respiratory infection and frequent accompanying diseases. Future diagnostic and therapeutic treatment depends on pleural fluid features and imaging lung findings.

Bacteriology and clinical outcomes of patients with culture-positive pleural infection in Western Australia: A 6-year analysis

BACKGROUND AND OBJECTIVE

Pleural infection is a clinical challenge; its microbiology can be complex. Epidemiological and outcome data of pleural infection in adult Australians are lacking. We describe the bacteriology and clinical outcomes of Australian adults with culture-positive pleural infection (CPPI) over a 6-year period.

METHODS

Cases with CPPI were identified through Western Australian public hospitals electronic record. Culture isolates, admission dates, vital status, co-morbidities, radiology, blood and pleural fluid tests were extracted.

RESULTS

In total, 601 cases (71.4% males; median age: 63 years (IQR: 50-74); median hospital stay 13 days) involving 894 bacterial isolates were identified. Hospital-acquired (HA)-CPPI was defined in 398 (66.2%) cases, community-acquired (CA)-CPPI in 164 (27.3%) cases and the remaining classified as oesophageal rupture/leak. Co-morbidities, most frequently cancer, were common (65.2%). Radiological evidence of pneumonia was present in only 43.8% of CA-CPPI and 27.3% of HA-CPPI. Of the 153 different bacterial strains cultured, Streptococcus species (32.9%) especially viridans streptococci group were most common in CA-CPPI, whereas HA-CPPI was most often associated with Staphylococcus aureus (11.6%) and Gram-negative (31.9%) infections. Mortality was high during hospitalization (CA-CPPI 13.4% vs HA-CPPI 16.6%; P = 0.417) and at 1 year (CA-CPPI 32.4% vs HA-CPPI 45.5%; P = 0.006).

CONCLUSION

This is the first large multicentre epidemiological study of pleural infection in Australian adults and includes the largest cohort of HA-CPPI published to date. CPPI is caused by a diverse range of organisms which vary between CA and HA sources. CPPI is a poor prognostic indicator both in the short term and in the subsequent 12 months.

The time course of resolution of adhesions during fibrinolytic therapy in tetracycline-induced pleural injury in rabbits

The time required for the effective clearance of pleural adhesions/organization after intrapleural fibrinolytic therapy (IPFT) is unknown. Chest ultrasonography and computed tomography (CT) were used to assess the efficacy of IPFT in a rabbit model of tetracycline-induced pleural injury, treated with single-chain (sc) urokinase plasminogen activators (scuPAs) or tissue PAs (sctPA). IPFT with sctPA (0.145 mg/kg; n = 10) and scuPA (0.5 mg/kg; n = 12) was monitored by serial ultrasonography alone (n = 12) or alongside CT scanning (n = 10). IPFT efficacy was assessed with gross lung injury scores (GLIS) and ultrasonography scores (USS). Pleural fluids withdrawn at 0-240 min and 24 h after IPFT were assayed for PA and fibrinolytic activities, α-macroglobulin/fibrinolysin complexes, and active PA inhibitor 1 (PAI-1). scuPA and sctPA generated comparable steady-state fibrinolytic activities by 20 min. PA activity in the scuPA group decreased slower than the sctPA group (kobs = 0.016 and 0.042 min(-1)). Significant amounts of bioactive uPA/α-macroglobulin (but not tPA; P < 0.05) complexes accumulated at 0-40 min after IPFT. Despite the differences in intrapleural processing, IPFT with either fibrinolysin was effective (GLIS ≤ 10) in animals imaged with ultrasonography only. USS correlated well with postmortem GLIS (r(2) = 0.85) and confirmed relatively slow intrapleural fibrinolysis after IPFT, which coincided with effective clearance of adhesions/organization at 4-8 h. CT scanning was associated with less effective (GLIS > 10) IPFT and higher levels of active PAI-1 at 24 h following therapy. We concluded that intrapleural fibrinolysis in tetracycline-induced pleural injury in rabbits is relatively slow (4-8 h). In CT-scanned animals, elevated PAI-1 activity (possibly radiation induced) reduced the efficacy of IPFT, buttressing the major impact of active PAI-1 on IPFT outcomes.

Pleurectomy decortication in the treatment of the "trapped lung" in benign and malignant pleural effusions

Trapped lung is defined by the inability of the lung to expand and fill the thoracic cavity because of a restricting "peel." This restriction may be secondary to a benign inflammatory or fibrotic cortex or to a malignant visceral pleural tumor. This condition has a significant impact on the patient's quality of life by causing dyspnea. This article discusses the role of surgery in relieving the trapped lung, including decortication in benign disease and pleurectomy in malignant disease. The surgical approaches of video-assisted thoracoscopy and thoracotomy are contrasted and the future potential for surgical trials in this condition is outlined.

Surgical management of pleural empyema in the very elderly

INTRODUCTION

Parapneumonic pleural empyema is a critical illness. Age is an acknowledged risk factor for both pneumonia and pleural empyema. Furthermore, elderly patients often have severe co-morbidity. In the case of pleural empyema, their clinical condition is likely to deteriorate fast, resulting in life threatening septic disease. To prevent this disastrous situation we adapted early surgical debridement as the primary treatment option even in very elderly patients. This study shows the outcome of surgically managed patients with pleural empyema who are 80 years or older.

METHODS

The outcomes of 222 consecutive patients who received surgical therapy for parapneumonic pleural empyema at a German tertiary referral hospital between 2006 and 2010 were reviewed in a retrospective case study. Patients older than 80 years were identified.

RESULTS

There were 159 male and 63 female patients. The mean age was 60.5 years and the overall in-hospital mortality rate was 7%. Of the 222 patients, 37 were 80 years or older (range: 80–95 years). The frequencies of predominantly cardiac co-morbidity and high ASA (American Society of Anesthesiologists) grades were significantly higher for very elderly patients (p<0.001). A minimally invasive approach was feasible in 34 cases (92%). Of the 37 patients aged over 80, 36 recovered while one died from severe sepsis (in-hospital mortality 3%). There was no significant difference in mortality between the very elderly and the younger sufferers (p=0.476).

CONCLUSIONS

Early surgical treatment of parapneumonic pleural empyema shows excellent results even in very elderly patients. Despite considerable co-morbidity and often delayed diagnosis, minimally invasive surgery was feasible in 34 patients (92%). The in-hospital mortality of very elderly patients was low. It can therefore be concluded that advanced age is no contraindication for early surgical therapy.

Serum amyloid alpha in parapneumonic effusions

STUDY OBJECTIVES

To assess serum amyloid alpha (SAA) pleural fluid levels in parapneumonic effusion (PPE) and to investigate SAA diagnostic performance in PPE diagnosis and outcome.

METHODS

We studied prospectively 57 consecutive patients with PPE (empyema (EMP), complicated (CPE), and uncomplicated parapneumonic effusion (UPE)). SAA, CRP, TNF-α, IL-1β, and IL-6 levels were evaluated in serum and pleural fluid at baseline. Patients were followed for 6-months to detect pleural thickening/loculations.

RESULTS

Pleural SAA levels (mg/dL) median(IQR) were significantly higher in CPE compared to UPE (P < 0.04); CRP levels were higher in EMP and CPE compared to UPE (P < 0.01). There was no significant difference between IL-1β, IL-6, TNF-α level in different PPE forms. No significant association between SAA levels and 6-month outcome was found. At 6-months, patients with no evidence of loculations/thickening had significantly higher pleural fluid pH, glucose levels (P = 0.03), lower LDH (P = 0.005), IL-1β levels (P = 0.001) compared to patients who presented pleural loculations/thickening.

CONCLUSIONS

SAA is increased in complicated PPE, and it might be useful as a biomarker for UPE and CPE diagnosis. SAA levels did not demonstrate considerable diagnostic performance in identifying patients who develop pleural thickening/loculations after a PPE.

Thoracoscopic management of empyema thoracis

Appropriate management of empyema thoracis is dependent upon a secure diagnosis of the etiology of empyema and the phase of development. Minimal access surgery using video-assisted thoracoscopy (VATS) is one of many useful techniques in treating empyema. Complex empyema requires adjunctive treatment in addition to VATS.

Thoracic Empyema in High-Risk Patients: Conservative Management or Surgery?

We retrospectively analyzed the data of 119 patients who were treated for empyema thoracis from 1999 to 2007. There were 87 men with a mean age of 63.9 years (range, 19–79 years) and 32 women with a mean age 55.2 years (range, 26–78 years). The empyema was right-sided in 73 patients and left-sided in 46. The etiology was parapneumonic in 43.7% of cases, postoperative in 42.0%, posttraumatic in 11.8%, and due to other causes in 2.5%. Eight (6.7%) patients underwent surgery on admission because of unstable clinical status; all 8 survived. Fibrinolysis was used in 111 (93.3%) patients; of these, 88 (73.9%) were successfully treated by intrapleural urokinase instillation, and 23 (19.4%) failed treatment and underwent surgery. All 88 patients who had successful fibrinolytic therapy survived, they accounted for 1.8% of the morbidity. In the 23 patients who underwent surgery after failed treatment, there were 3 deaths, accounting for 2.7% overall mortality and 6.3% morbidity. Treating thoracic empyema in patients with significant comorbidities is challenging. Intrapleural urokinase administration might be beneficial in high-risk patients, but in those without significant comorbidities, early surgery may be considered.

The relationship between chest tube size and clinical outcome in pleural infection

BACKGROUND

The optimal choice of chest tube size for the treatment of pleural infection is unknown, with only small cohort studies reported describing the efficacy and adverse events of different tube sizes.

METHODS

A total of 405 patients with pleural infection were prospectively enrolled into a multicenter study investigating the utility of fibrinolytic therapy. The combined frequency of death and surgery, and secondary outcomes (hospital stay, change in chest radiograph, and lung function at 3 months) were compared in patients receiving chest tubes of differing size (chi(2), t test, and logistic regression analyses as appropriate). Pain was studied in detail in 128 patients.

RESULTS

There was no significant difference in the frequency with which patients either died or required thoracic surgery in patients receiving chest tubes of varying sizes ( < 10F, number dying or needing surgery 21/58 [36%]; size 10-14F, 75/208 [36%]; size 15-20F, 28/70 [40%]; size > 20F, 30/69 [44%]; chi(2)trend, 1 degrees of freedom [df] = 1.21, P = .27), nor any difference in any secondary outcome. Pain scores were substantially higher in patients receiving (mainly blunt dissection inserted) larger tubes ( < 10F, median pain score 6 [range 4-7]; 10-14F, 5 [4-6]; 15-20F, 6 [5-7]; > 20F, 6 [6-8]; chi(2), 3 df = 10.80, P = .013, Kruskal-Wallis; chi(2)trend, 1 df = 6.3, P = .014).

CONCLUSIONS

Smaller, guide-wire-inserted chest tubes cause substantially less pain than blunt-dissection-inserted larger tubes, without any impairment in clinical outcome in the treatment of pleural infection. These results suggest that smaller size tubes may be the initial treatment of choice for pleural infection, and randomized studies are now required.

TRIAL REGISTRATION

MIST1 trial ISRCTN number: 39138989.

Current surgical treatment of thoracic empyema in adults

A review of the recent literature on treatment modalities of adult thoracic empyema was conducted in order to expose the controversies and verify where consensus exists. Critical reading filtered through clinical experience was the method followed. The roles of surgical drainage, lavage techniques, debridement via VATS, decortication, thoracoplasty and open window thoracostomy were considered using the Oxford Center of Evidence Based Medicine criteria. The roles of the different therapeutical modalities were interpreted in the light of the triphasic nature of empyema thoracis. The randomised controlled trials came up with conflicting results. With two exceptions all of the papers reviewed provide level (2b) or below evidences. The lack of a single ideal treatment modality or policy reflects the complexity of the diagnosis and staging of this heterogeneous disease. Basic elements of intervention--drainage, different evacuation techniques, decortication, thoracoplasty and open window thoracostomy--are well-established technical modalities; however, neither a universally acceptable primary modality nor the gold standard of their sequence is available. Drainage remains to be the initial treatment modality in Phase I disease. Debridement via VATS is a safe, reliable and efficient method in the fibrinopurulent phase. Organised pleural callus requires formal decortication. Open window thoracostomy is a simple and safe procedure for high-risk patients and results in quick detoxication. Thoracoplasty kept its final role in pleural space management. Acute postoperative bronchial stump insufficiency requires immediate surgery. Evacuation of toxic material is mandatory. No single-stage procedure offers a solution. An optimised agressivity treatment modality should be tailored to the condition of the patient and to the potential of the persisting cavity. Decision-making involves a triad consisting of the aetiology of empyema (i.e. primary vs secondary), general condition of the patient and stage of disease, while considering the triphasic nature of development of thoracic empyema. The current attitudes show that the present concepts are based mainly on expert opinion. Flexibility and patience on behalf of the surgeon and nursing staff, the patient and the hospital management, as well as a good understanding of the complexity of this condition are the cornerstones of the treatment. No exclusive sequence of procedures leading to a uniformly predictable successful outcome is available. Individualised approaches can be recommended based on institutional practice and local protocols. Thoracic empyema in general seems to remain resilient to fit completely into the categories of evidence-based medical approach.

Bacteriology of complicated parapneumonic effusions

PURPOSE OF REVIEW

The bacteriology of complicated parapneumonic effusions has changed in recent decades, but the causative organisms often remain obscure in up to 40% of cases. Recently, new molecular methods have become available which might help clinical management and improve our understanding of this condition. In this review, we will consider the current bacteriological spectrum of pleural infection and look at some of the new molecular methods.

RECENT FINDINGS

Hospital-acquired pleural infection exhibits a different bacteriology than pleural infection originating in the community. It carries a significantly higher mortality and requires different antibiotics at presentation. Streptococcal and anaerobic infections have low associated mortalities whereas staphylococcal, enterobacterial and mixed aerobic infections carry a worse prognosis. The yield of causative organisms can be significantly increased by the use of bacterial nucleic acid amplification and this may have a role in routine clinical practice in the near future.

SUMMARY

The bacteriology of pleural infection has changed markedly in recent years. Mortality is highest with hospital-acquired pleural infection and infections caused by staphylococci, Enterobacteriacae and mixed aerobes. New molecular microbiological methods substantially increase bacterial yield in pleural fluid.