Association between intrapleural urokinase monotherapy and treatment failure in patients with pleural infection: a retrospective cohort study.

BACKGROUND: Pleural infection, an infection of the pleural space, is frequently treated with antibiotics and thoracic tube drainage. In case of insufficient drainage, an intrapleural fibrinolytic agent is considered before surgical intervention. However, the effectiveness of fibrinolytic monotherapy is still controversial. Therefore, we aimed to examine the association between urokinase monotherapy and treatment failure in patients with pleural infection. METHODS: In this retrospective observational study, patients with pleural infection underwent chest tube insertion were divided into two groups including patients treated with or without intrapleural instillation of urokinase. The propensity score overlap weighting was used to balance the baseline characteristics between the groups. Treatment failure was defined by the composite primary outcome of in-hospital death and referral for surgery. RESULTS: Among the 94 patients, 67 and 27 patients were in the urokinase and non-urokinase groups, respectively. Urokinase monotherapy improved the composite outcome between the groups (19.4% vs. 48.1%, p = 0.01). After adjusting using propensity score overlap weighting, urokinase monotherapy improved the composite outcome compared to the non-urokinase group (19.0% vs. 59.5%, p = 0.003). CONCLUSIONS: Urokinase monotherapy can be an important nonsurgical treatment option for patients with pleural infection. TRIAL REGISTRATION: The participants were retrospectively registered.

Alteplase Dose Assessment for Pleural infection Therapy (ADAPT) Study-2: Use of 2.5 mg alteplase as a starting intrapleural dose.

BACKGROUND AND OBJECTIVE: Intrapleural tissue plasminogen activator/deoxyribonuclease (tPA/DNase) therapy is increasingly used in pleural infection. Bleeding risks and costs associated with tPA remain the clinical concerns. Our dose de-escalation series aims to establish the lowest effective dosing regimen for tPA/DNase. This study assesses the intrapleural use of 2.5 mg tPA/5 mg DNase for pleural infection. METHODS: Consecutive patients with pleural infection treated with a starting regime of 2.5 mg tPA/5 mg DNase were included from two centres in Australia and UK. Escalation of tPA dose was permitted if clinical response was inadequate. RESULTS: Sixty-nine patients (mean age 61.0 years) received intrapleural 2.5 mg tPA/5 mg DNase. Most (88.4%) were treated successfully and discharged from hospital without surgery by 90 days. Patients received a median of 5 [interquartile range [IQR] = 3-6] doses of tPA/DNase. Total amount of tPA used per patient was 12.5 mg [median, IQR = 7.5-15.0]. Seventeen patients required dose escalation of tPA; most (n = 12) for attempted drainage of distant non-communicating locule(s). Treatment success was corroborated by clearance of pleural opacities on radiographs (from median 27.0% [IQR = 17.1-44.5] to 11.0% [IQR = 6.4-23.3] of hemithorax, p < 0.0001), increased pleural fluid drainage (1.98 L [median, IQR = 1.38-2.68] over 72 h following commencement of tPA/DNase) and reduction of serum C-reactive protein level (by 45.0% [IQR = 39.3-77.0] from baseline at day 5, p < 0.0001). Two patients required surgery. Six patients with significant comorbidities (e.g., advanced cancer) had ongoing infection when palliated and died. Two patients experienced self-limiting pleural bleeding and received blood transfusion. CONCLUSION: A starting intrapleural regime of 2.5 mg tPA/5 mg DNase, with up-titration if needed, can be effective and deserves further exploration.

A Large Central Bronchopleural Fistula Closed by Bronchoscopic Administration of Recombinant Bovine Basic Fibroblast Growth Factor: A Case Report.

A large central bronchopleural fistula (BPF) surrounded by mediastinal tissue was successfully closed by local administration of recombinant bovine basic fibroblast growth factor (rbFGF) using the bronchoscope. No complications were observed during and after this bronchoscopic treatment. This is the first report of the bronchoscopic treatment of a large central BPF by the local spray of rbFGF. The bronchoscopic treatment with rbFGF is a potentially cost-effective method for central BPF surrounded by mediastinal tissue.

Intrapleural Fibrinolytics and Deoxyribonuclease for Treatment of Indwelling Pleural Catheter-Related Pleural Infection: A Multi-Center Observational Study.

BACKGROUND: Indwelling pleural catheters (IPC) are increasingly used for management of recurrent (especially malignant) effusions. Pleural infection associated with IPC use remains a concern. Intrapleural therapy with tissue plasminogen activator (tPA) and deoxyribonuclease (DNase) significantly reduces surgical referrals in non-IPC pleural infection, but data on its use in IPC-related pleural infection are scarce. OBJECTIVE: To assess the safety and efficacy of intrapleural tPA and DNase in IPC-related pleural infection. METHODS: Patients with IPC-related pleural infection who received intrapleural tPA/DNase in five Australian and UK centers were identified from prospective databases. Outcomes on feasibility of intrapleural tPA/DNase delivery, its efficacy and safety were recorded. RESULTS: Thirty-nine IPC-related pleural infections (predominantly Staphylococcus aureus and gram-negative organisms) were treated in 38 patients; 87% had malignant effusions. In total, 195 doses (median 6 [IQR = 3-6]/patient) of tPA (2.5 mg-10 mg) and DNase (5 mg) were instilled. Most (94%) doses were delivered via IPCs using local protocols for non-IPC pleural infections. The mean volume of pleural fluid drained during the first 72 h of treatment was 3,073 (SD = 1,685) mL. Most (82%) patients were successfully treated and survived to hospital discharge without surgery; 7 required additional chest tubes or therapeutic aspiration. Three patients required thoracoscopic surgery. Pleurodesis developed post-infection in 23/32 of successfully treated patients. No major morbidity/mortality was associated with tPA/DNase. Four patients received blood transfusions; none had systemic or significant pleural bleeding. CONCLUSION: Treatment of IPC-related pleural infection with intrapleural tPA/DNase instillations via the IPC appears feasible and safe, usually without additional drainage procedures or surgery. Pleurodesis post-infection is common.

Pleural Thickening after Pleural Effusion: How can we Follow-Up in Children?

INTRODUCTION: No clear information exists about the factors affecting pleural thickening following parapneumonic effusion in children. We aimed to investigate factors that affect the resolving time of pleural thickening after parapneumonic effusion. METHODS: Between the years of 2007-18, 91 patients, which were followed due to diagnosis of pleural thickening after parapneumonic effusion, were assessed. Ages, complaints, physical examination findings, laboratory results, chest x-ray and ultrasonography findings, treatments, duration of treatment and recovery time of the patients were examined terms in of pleural thickening resolving time. RESULTS: The mean age of patients was 7.5 ± 5.0 years. Pleural thickening resolving time was 151 ± 6.8 days. The resolving time for pleural thickening was delayed with older ages, longer duration of complaints, fever before hospital admission and treatment, lower oxygen saturation at the time of admission, crackles in the physical examination, higher white blood cell count and pleural fluid density (p = 0.018, p = 0.001, p = 0.021, p = 0.020, p = 0.024, p = 0.025, p = 0.021, p = 0.019). In addition, the amount of effusion measured by thorax ultrasonography, fibrinolytic usage, and complications had a role in the delayed resolving time (p = 0.034, p = 0.001, p = 0.034). Pleural thickening resolved in 80% of the patients. CONCLUSION: In this report, 80% of pleural thickening, following parapneumonic effusion resolved within 5 months. Patients who do not have a complication during follow-up are not required to monitor with frequent chest x-ray. Patients with a higher amount of pleural effusion, complications and need for fibrinolytic treatment should be followed more carefully.

Lower-lobe predominant pleuroparenchymal fibroelastosis.

Upper-lobe predominance of elastofibrosis is agreed upon for the diagnosis of clinical pleuroparenchymal fibroelastosis (PPFE). We herein describe a patient with dermatomyositis-related interstitial pneumonia with a histology of lower-lobe predominant PPFE. A 71-year-old woman who had been diagnosed with dermatomyositis-related interstitial pneumonia died of respiratory failure. The computed tomography patterns of the lower lobes showed reticular and ground-glass opacities with traction bronchiectasis. An autopsy revealed that the bilateral lower lobes were sclerotic with decreased air volume. A microscopic examination of the lower lobes showed pleural fibrosis and subpleural elastofibrosis without the structural destruction, indicative of histological PPFE. PPFE histology was also evident in the upper lobes but relatively modest compared to that of the lower lobes. In addition, because the computed tomography images of the patient were suggestive of non-PPFE-type fibrosis, lower-lobe dominant PPFE might be overlooked in daily practice.

Thoracic Hyper-IgG4-Related Disease Mimicking Malignant Pleural Mesothelioma.

We report a rare case of a IgG4-related disease presenting with recurrent pleural effusion, pleural thickness and multiple mediastinal lymphadenopathies and no involvement of other extrathoracic organs. A 65-year-old man with a previous asbestos exposure presented with cough and pain discomfort. A large right pleural effusion was detected and evacuated (siero-haematic liquid). With the suspicious of a pleural mesothelioma, a CT-scan before and a 18F-FDG PET/CT-scan later were performed revealing multiple pleural thickenings and multiple mediastinal lymphadenopathies with radiotracer uptake. EBUS-TBNA EBUS-TBNA did not result in a formal pathological diagnosis; thus, multiple pleural biopsy were performed via right thoracoscopy. At pathology the pleura was markedly thickened by a chronic fibroinflammatory process with scattered lymphoid follicles and a large number of mature plasma cells. Immunohistochemistry shows a mixed B (CD20+) and T (CD3+) population of lymphocytes, without light chain restriction and an increased number of IgG4-positive plasma cells. A presumptive diagnosis of IgG4-related disease was formulated. Total body CT-scan excluded other organ involvement. Blood test showed elevated serum IgG4 concentrations (253 mg/dL) and mild elevation of acute-phase reactants (C-reactive protein 10.7 mg/L). Autoimmune profile was negative. A diagnosis of definite IgG4-related disease was made, and treatment with prednisone 50 mg/day was started.

The first use of combination of Intrapleural Fibrinolytics (Alteplase & DNAse) for pleural infection in Malaysia.

The use of a combination of intrapleural fibrinolytics or tissue plasminogen activator(tPA) Alteplase and deoxyribonuclease (Dnase) has been increasing for cases of complicated pleural infection/parapneumonic effusion worldwide. Its efficacy and success rate in selected cases of complicated parapneumonic effusion unresponsive to antibiotics and chest drainage are well documented. This case report demonstrates the first use of combination intrapleural fibrinolytic (Alteplase) and DNAse (Pulmozyme) in Malaysia for a case of pleural infection/parapneumonic effusion.

Targeting plasminogen activator inhibitor-1 in tetracycline-induced pleural injury in rabbits.

Elevated active plasminogen activator inhibitor-1 (PAI-1) has an adverse effect on the outcomes of intrapleural fibrinolytic therapy (IPFT) in tetracycline-induced pleural injury in rabbits. To enhance IPFT with prourokinase (scuPA), two mechanistically distinct approaches to targeting PAI-1 were tested: slowing its reaction with urokinase (uPA) and monoclonal antibody (mAb)-mediated PAI-1 inactivation. Removing positively charged residues at the "PAI-1 docking site" (179RHRGGS184→179AAAAAA184) of uPA results in a 60-fold decrease in the rate of inhibition by PAI-1. Mutant prourokinase (0.0625-0.5 mg/kg; n = 12) showed efficacy comparable to wild-type scuPA and did not change IPFT outcomes ( P > 0.05). Notably, the rate of PAI-1-independent intrapleural inactivation of mutant uPA was 2 times higher ( P < 0.05) than that of the wild-type enzyme. Trapping PAI-1 in a "molecular sandwich"-type complex with catalytically inactive two-chain urokinase with Ser195Ala substitution (S195A-tcuPA; 0.1 and 0.5 mg/kg) did not improve the efficacy of IPFT with scuPA (0.0625-0.5 mg/kg; n = 11). IPFT failed in the presence of MA-56A7C10 (0.5 mg/kg; n = 2), which forms a stable intrapleural molecular sandwich complex, allowing active PAI-1 to accumulate by blocking its transition to a latent form. In contrast, inactivation of PAI-1 by accelerating the active-to-latent transition mediated by mAb MA-33B8 (0.5 mg/kg; n = 2) improved the efficacy of IPFT with scuPA (0.25 mg/kg). Thus, under conditions of slow (4-8 h) fibrinolysis in tetracycline-induced pleural injury in rabbits, only the inactivation of PAI-1, but not a decrease in the rate of its reaction with uPA, enhances IPFT. Therefore the rate of fibrinolysis, which varies in different pathologic states, could affect the selection of PAI-1 inhibitors to enhance fibrinolytic therapy.

Restrictive lung defects: parenchymal, chest wall and neuromuscular.

Sarcoidosis is a multisystem condition which may affect a number of organs and, within the cardiopulmonary system, most commonly manifests as parenchymal, airway-centred, nodal, vascular or cardiac disease. Pleural involvement is rare, but well described, and often presents as pleural effusions or pleural thickening. Here, we present the first case of active sarcoidosis manifesting as bilateral pleural calcification. We highlight the importance of a nuanced understanding of pulmonary physiology when dissecting coexistent extrathoracic and intrathoracic pulmonary restriction. We demonstrate the value of positron emission tomography scanning for identification of sites of sarcoid activity, in this case the pleura, to ensure tissue confirmation of this rare but functionally important manifestation of disease. Sarcoidosis should be considered within the differential diagnosis for patients with pleural calcification, not explained by more common causes.

Inhibition of angiotensin II and calpain attenuates pleural fibrosis.

Pleural fibrosis is associated with various inflammatory processes such as tuberculous pleurisy and bacterial empyema. There is currently no ideal therapeutic to attenuate pleural fibrosis. Some pro-fibrogenic mediators induce fibrosis through inflammatory processes, suggesting that blockage of these mediators might prevent pleural fibrosis. The MeT-5A human pleural mesothelial cell line (PMC) was used in this study as an in vitro model of fibrosis; and intra-pleural injection of bleomycin with carbon particles was used as an in vivo mouse model of pleural fibrosis. Calpain knockout mice, calpain inhibitor (calpeptin), and angiotensin (Ang) II type 1 receptor (AT1R) antagonist (losartan) were evaluated in prevention of experimental pleural fibrosis. We found that bleomycin and carbon particles induced calpain activation in cultured PMCs. This in vitro response was associated with increased collagen-I synthesis, and was blocked by calpain inhibitor or AT1R antagonist. Calpain genetic or treatment with calpeptin or losartan prevented pleural fibrosis in a mouse model induced by bleomycin and carbon particles. Our findings indicate that Ang II signaling and calpain activation induce collagen-I synthesis and contribute to fibrotic alterations in pleural fibrosis. Inhibition of Ang II and calpain might therefore be a novel strategy in treatment of pleural fibrosis.

Erdheim Chester disease with appendicular skeletal, renal and pleural involvement responding to Zelboraf (BRAF inhibitor) treatment: case report.

Erdheim Chester disease is a rare non-Langerhans cell histiocytosis which may involve multiple organs including bone, soft tissue, lungs, cardiovascular system, kidneys (retroperitoneum), skin, and central nervous system. Bone involvement is most common followed by other organs. This case report describes a 58-year-old man who presented with progressive renal dysfunction presumed due to obstruction. The patient failed multiple urinary tract interventions, and clinical course was complicated by recurrent low-grade fevers, and bilateral knee pain. Advanced imaging and histopathological features on bone biopsy were consistent with Erdheim Chester disease. Molecular studies of tissue showed BRAF V600 mutation. This patient was treated with Zelboraf (vemurafenib) BRAF inhibitor with subsequent improvement in renal and pleural dysfunction as well as decreased histiocytic soft tissue masses on CT.

Targeting of plasminogen activator inhibitor 1 improves fibrinolytic therapy for tetracycline-induced pleural injury in rabbits.

Endogenous active plasminogen activator inhibitor 1 (PAI-1) was targeted in vivo with monoclonal antibodies (mAbs) that redirect its reaction with proteinases to the substrate branch. mAbs were used as an adjunct to prourokinase (single-chain [sc] urokinase [uPA]) intrapleural fibrinolytic therapy (IPFT) of tetracycline-induced pleural injury in rabbits. Outcomes of scuPA IPFT (0.25 or 0.0625 mg/kg) with 0.5 mg/kg of mouse IgG or mAbs (MA-33H1F7 and MA-8H9D4) were assessed at 24 hours. Pleural fluid (PF) was collected at 0, 10, 20, and 40 minutes and 24 hours after IPFT and analyzed for plasminogen activating (PA), uPA, fibrinolytic activities, levels of total plasmin/plasminogen, α-macroglobulin (αM), mAbs/IgG antigens, free active uPA, and αM/uPA complexes. Anti-PAI-1 mAbs, but not mouse IgG, delivered with an eightfold reduction in the minimal effective dose of scuPA (from 0.5 to 0.0625 mg/kg), improved the outcome of IPFT (P < 0.05). mAbs and IgG were detectable in PFs at 24 hours. Compared with identical doses of scuPA alone or with IgG, treatment with scuPA and anti-PAI-1 mAbs generated higher PF uPA amidolytic and PA activities, faster formation of αM/uPA complexes, and slower uPA inactivation. However, PAI-1 targeting did not significantly affect intrapleural fibrinolytic activity or levels of total plasmin/plasminogen and αM antigens. Targeting PAI-1 did not induce bleeding, and rendered otherwise ineffective doses of scuPA able to improve outcomes in tetracycline-induced pleural injury. PAI-1-neutralizing mAbs improved IPFT by increasing the durability of intrapleural PA activity. These results suggest a novel, well-tolerated IPFT strategy that is tractable for clinical development.

Therapeutic drug monitoring and the conservative management of chronic tuberculous empyema: case report and review of the literature.

BACKGROUND: Chronic tuberculous empyema (CTE) is a rare and unusual, low grade and protracted, infection of the pleural space resulting in marked thickening, even calcification of the visceral and parietal pleura. Historically its management has been extraordinarily challenging. Differential penetration of anti-TB drugs into the pleural space has resulted in acquired drug resistance and surgery to remove the empyema or close a complicating bronchopleural fistula (BPF) has been technically difficult or unacceptably hazardous. On the basis of limited experience, the combination of tube thoracostomy or catheter drainage and high-end dosing of anti-TB drugs has been recommended as an initial approach to these lesions. Herein we report the first well documented case of closure of a BPF and cure of a CTE using this approach. The chances of a favorable outcome are improved, we suggest, by using therapeutic drug monitoring (TDM) to guide high-end drug dosing. CASE PRESENTATION: An 84 year old male immigrant to Canada from Croatia was diagnosed with a CTE after he developed a BPF. The diagnosis was made 62 years after what was, in retrospect, an episode of tuberculous pleurisy. He was treated with computed tomography-guided catheter drainage and TDM-guided high-end dosed anti-TB drugs (serum and pleural fluid drug concentrations) over a 10 month period. Sustained closure of the BPF and mycobacteriologic cure of the CTE was achieved. Drug concentrations in the present case and all other reported cases are summarized and interpreted. CONCLUSION: When serum concentrations of the anti-TB drugs isoniazid, pyrazinamide and ethambutol at the high end of the normal range are achieved, pleural fluid concentrations at the low end of the normal range may be anticipated in CTE. Though highly protein bound drugs such as rifampin and moxifloxacin appear to penetrate CTEs less well, their free concentrations in the pleural space may be proportionately higher on account of lower protein concentrations. Interventional radiology and TDM increase the chances that conservative management of CTE will be successful.

Intrapleural use of tissue plasminogen activator and DNase in pleural infection.

BACKGROUND: More than 30% of patients with pleural infection either die or require surgery. Drainage of infected fluid is key to successful treatment, but intrapleural fibrinolytic therapy did not improve outcomes in an earlier, large, randomized trial. METHODS: We conducted a blinded, 2-by-2 factorial trial in which 210 patients with pleural infection were randomly assigned to receive one of four study treatments for 3 days: double placebo, intrapleural tissue plasminogen activator (t-PA) and DNase, t-PA and placebo, or DNase and placebo. The primary outcome was the change in pleural opacity, measured as the percentage of the hemithorax occupied by effusion, on chest radiography on day 7 as compared with day 1. Secondary outcomes included referral for surgery, duration of hospital stay, and adverse events. RESULTS: The mean (±SD) change in pleural opacity was greater in the t-PA-DNase group than in the placebo group (-29.5±23.3% vs. -17.2±19.6%; difference, -7.9%; 95% confidence interval [CI], -13.4 to -2.4; P=0.005); the change observed with t-PA alone and with DNase alone (-17.2±24.3 and -14.7±16.4%, respectively) was not significantly different from that observed with placebo. The frequency of surgical referral at 3 months was lower in the t-PA-DNase group than in the placebo group (2 of 48 patients [4%] vs. 8 of 51 patients [16%]; odds ratio for surgical referral, 0.17; 95% CI, 0.03 to 0.87; P=0.03) but was greater in the DNase group (18 of 46 patients [39%]) than in the placebo group (odds ratio, 3.56; 95% CI, 1.30 to 9.75; P=0.01). Combined t-PA-DNase therapy was associated with a reduction in the hospital stay, as compared with placebo (difference, -6.7 days; 95% CI, -12.0 to -1.9; P=0.006); the hospital stay with either agent alone was not significantly different from that with placebo. The frequency of adverse events did not differ significantly among the groups. CONCLUSIONS: Intrapleural t-PA-DNase therapy improved fluid drainage in patients with pleural infection and reduced the frequency of surgical referral and the duration of the hospital stay. Treatment with DNase alone or t-PA alone was ineffective. (Funded by an unrestricted educational grant to the University of Oxford from Roche UK and by others; Current Controlled Trials number, ISRCTN57454527.).

Management of parapneumonic effusions and empyema.

Pleural infection remains a common and serious respiratory condition with important implications for patients and health-care services. This review will cover the management of pleural infection including medical treatment, the role of intrapleural agents and surgical treatment. We discuss the directions that future research in this important area might take. Increasing incidence of pleural infection has been reported worldwide without a clear explanation. The pathogens responsible for pleural infection differ from those in pneumonia. Proper antibiotic selection and pleural fluid drainage remain the cornerstones of treatment. There is no evidence in adult pleural infection to support the routine use of intrapleural fibrinolytics to alter clinically meaningful outcomes; however, combined intrapleural tissue plasminogen activator (tPA) and deoxyribonuclease (DNase) therapy may have a future role. The role of medical thoracoscopy remains unproven. Surgical referral should be considered in patients who fail to respond to standard medical management after 5 to 7 days. Despite advances in microbiology, medical management, and surgery, the mortality of pleural infection at one year remains approximately 20% for the last two decades. Future studies are required to validate predictive scores for patients' stratification (RAPID score) and the role of fibrinolytics (combination of tPA plus DNase). Surgical drainage remains a vital treatment option, but ongoing research is required to define the group of patients who would benefit most and when, in the disease course, this treatment should be offered.

Expect the unexpected: pleuro-pulmonary melioidosis in a renal transplant recipient.

Melioidosis is an infectious disease endemic in tropical northern Australia and Southeast Asia, and, if treated late or inappropriately, is usually fatal. We report a rare case of pleuro-pulmonary melioidosis with septicemia in a renal transplant recipient to highlight the potential risk of acquiring this infection in at-risk patients living in, or visiting, regions that are endemic for melioidosis, and to convey the importance of its early diagnosis and specific treatment.

Non-steroidal anti-inflammatory drugs reduce pleural adhesion in human: evidence from redo surgery.

Non-steroidal anti-inflammatory drugs (NSAIDs) reduced pleural adhesion in animal studies, but its effect on human had not been studied. A retrospective study was carried out for patients with solitary pulmonary nodules without a pre-operative tissue diagnosis positive for malignancy. The impact of the use of NSAIDs after stage one wedge resection was assessed by the degree of pleural adhesions encountered during second-stage, redo completion lobectomy. From April 2016 to March 2022, 50 consecutive patients meeting the inclusion criteria were included, and 44 patients were selected for analysis after exclusion (Treatment group with NSAID: N = 27; Control group without NSAID: N = 17). The preoperative characteristics and the final tumor pathologies were similar between the groups. The use of NSAID was significantly associated with lower risk of severe pleural adhesions and complete pleural symphysis (risk difference = -29%, p = 0.03). After controlling the effect of tumor size and chest drain duration, only the use of NSAID was statistically associated with the lowered risk of severe pleural adhesions and complete pleural symphysis. No statistically significant effects of NSAID on operative time (p = 0.86), blood loss (p = 0.72), and post-operative length of stay (p = 0.72) were demonstrated. In human, NSAIDs attenuated the formation of pleural adhesions after pleural disruptions. Physicians and surgeons should avoid the use of NSAIDs when pleural adhesion formation is the intended treatment outcome.

Intrapleural agents for pleural infection: fibrinolytics and beyond.

PURPOSE OF REVIEW: Pleural infection is a common, increasing clinical problem with a high morbidity and mortality. Medical management of pleural infection often fails, requiring invasive thoracic surgery to drain infected pleural collections, and for many years intrapleural agents have been assessed to reduce the need for surgical drainage and improve clinical outcomes. Randomized trials assessing intrapleural fibrinolytic agents have given conflicting results, and recent evidence provides important information on the role of intrapleural agents in the treatment of pleural infection, and the possible biology associated with infection progression in these patients. RECENT FINDINGS: Pleural infection is increasing in both the adult and paediatric populations. The combined previous evidence assessing intrapleural fibrinolytics alone in pleural infection suggests lack of efficacy for clinically important outcomes. The Multi-Centre Intrapleural Sepsis Trial 2 (MIST2) study provides the first evidence of a novel treatment combination [intrapleural tissue plasminogen activator (tPA) combined with intrapleural deoxyribonuclease (DNase)], which significantly improves the chest radiograph compared with either agent alone or placebo, and has potentially important benefits to important clinical outcomes (need for surgery and hospital stay). The precise mechanism of action of combination fibrinolytic and DNase in pleural infection is speculative. SUMMARY: Fibrinolytic therapy alone has not been proven to be of use in the treatment of pleural infection. The MIST2 study provides clear-cut evidence demonstrating improved chest radiographs, and highly suggestive secondary outcomes suggesting improved clinically important outcomes, using a combination of intrapleural tPA and DNase. This novel treatment combination may represent an important step in our understanding and treatment of pleural infection; however, larger clinical studies specifically addressing important clinical outcomes and further laboratory research describing the potential mechanisms of action are now required.

New strategies to manage complicated pleural effusions.

BACKGROUND: More than 30% of patients with pleural infection either die or require surgery. Drainage of infected fluid is the key to successful treatment, but intrapleural fibrinolytic therapy did not improve outcomes in an earlier, large, randomized trial therapy (Multicenter Intrapleural Sepsis Trial [MIST1]). METHODS: Objective: To evaluate the efficacy and safety of intrapleural DNase alone, alteplase alone, or the combination of both, to improve pleural drainage. Design: Multicenter, double-blind, double-dummy, 2 × 2 factorial randomized trial. Setting: Eleven centers in the United Kingdom (UK). Subjects: Adult patients (mean age 59 years, 72% men), who had clinical evidence of infection, and pleural fluid that had macroscopic purulence, a positive culture or Gram stain for bacteria, or a pH < 7.2. Intervention: Patients were assigned to 1 of the 4 study interventions for 3 days: double placebo, intrapleural tissue plasminogen activator (t-PA) and DNase, t-PA and placebo, or DNase and placebo. Outcomes: The primary outcome was the change in pleural opacity, measured as the percentage of the hemithorax occupied by effusion, on chest radiography on day 7 as compared with day 1. Secondary outcomes included referral for surgery, duration of hospital stay, and adverse events. RESULTS: The mean (± SD) change in pleural opacity was greater in the t-PA-DNase group than in the placebo group (-29.5 ± 23.3% vs. -17.2 ± 19.6%; difference, -7.9%; 95% confidence interval [CI], -13.4 to -2.4; P = 0.005). The change observed with t-PA alone and with DNase alone (-17.2 ± 24.3 and -14.7 ± 16.4%, respectively) was not significantly different from that observed with placebo. The frequency of surgical referral at 3 months was lower in the t-PA-DNase group than in the placebo group (2 of 48 patients [4%] vs. 8 of 51 patients [16%]; odds ratio for surgical referral, 0.17; 95% CI, 0.03 to 0.87; P = 0.03) but was greater in the DNase group (18 of 46 patients [39%]) than in the placebo group (odds ratio, 3.56; 95% CI, 1.30 to 9.75; P = 0.01). Combined t-PA-DNase therapy was associated with a reduction in the hospital stay, as compared with placebo (difference, -6.7 days; 95% CI, -12.0 to -1.9; P = 0.006). Hospital stay with either agent alone was not significantly different from that with placebo. The frequency of adverse events did not differ significantly among the groups. CONCLUSIONS: Intrapleural t-PA-DNase therapy improved fluid drainage in patients with pleural infection and reduced the frequency of surgical referral and the duration of hospital stay. Treatment with DNase alone or t-PA alone was ineffective.