Whole lung lavage therapy for pulmonary alveolar proteinosis: a global survey of current practices and procedures

A case of autoimmune pulmonary alveolar proteinosis responding to oral statin therapy

There is no approved drug treatment for autoimmune pulmonary alveolar proteinosis (APAP), although traditionally requires complex treatments such as whole lung lavage (WLL). We herein report on a 67-year-old man diagnosed with APAP. Treatment with atorvastatin (5 mg daily) resulted in significant improvement in symptoms, lung function, and computed tomography findings, with enhanced oxygenation, although serum anti-GM-CSF antibody levels remained elevated. This case suggests that the remission observed in this case could potentially be attributed to a direct effect of atorvastatin within the pulmonary alveoli. Statins may be considered as one of the treatment options for APAP.

Ten-year experience of whole lung lavage in pediatric Pulmonary Alveolar Proteinosis

BACKGROUND

Pulmonary Alveolar Proteinosis (PAP) is extremely rare and can be caused by hereditary dysfunction of the granulocyte macrophage colony-stimulating factor receptor (GM-CSF) receptor, autoantibodies against GM-CSF, or other diseases leading to alveolar macrophage (AM) dysfunction. This leads to protein accumulation in the lung and severe dyspnea and hypoxemia. Whole lung lavage (WLL) is the first line treatment strategy.

METHODS

Here, we present data from more than ten years of WLL practice in pediatric PAP. WLL performed by the use of a single lumen or double lumen tube (SLT vs. DLT) were compared for technical features, procedure time, and adverse events.

RESULTS

A total of n=57 procedures in six PAP patients between 3.5 and 14.3 years of age were performed. SLT based WLL in smaller children was associated with comparable rates of adverse events but with longer intervention times and postprocedural intensive care treatment when compared to DLT based procedures.

DISCUSSION

Our data shows that WLL is feasible even in small children. DLT based WLL seems to be more effective, and our data supports the notion that it should be considered as early as possible in pediatric PAP.

CONCLUSION

WLL lavage is possible in small PAP patients but should performed in close interdisciplinary cooperation and with age appropriate protocols.

Pulmonary Alveolar Proteinosis and new therapeutic concepts

Pulmonary alveolar proteinosis (PAP) is an umbrella term used to refer to a pulmonary syndrome which is characterized by excessive accumulation of surfactant in the lungs of affected individuals. In general, PAP is a rare lung disease affecting children and adults, although its prevalence and incidence is variable among different countries. Even though PAP is a rare disease, it is a prime example on how modern medicine can lead to new therapeutic concepts, changing ways and techniques of (genetic) diagnosis which ultimately led into personalized treatments, all dedicated to improve the function of the impaired lung and thus life expectancy and quality of life in PAP patients. In fact, new technologies, such as new sequencing technologies, gene therapy approaches, new kind and sources of stem cells and completely new insights into the ontogeny of immune cells such as macrophages have increased our understanding in the onset and progression of PAP, which have paved the way for novel therapeutic concepts for PAP and beyond. As of today, classical monocyte-derived macrophages are known as important immune mediator and immune sentinels within the innate immunity. Furthermore, macrophages (known as tissue resident macrophages (TRMs)) can also be found in various tissues, introducing e. g. alveolar macrophages in the broncho-alveolar space as crucial cellular determinants in the onset of PAP and other lung disorders. Given recent insights into the onset of alveolar macrophages and knowledge about factors which impede their function, has led to the development of new therapies, which are applied in the context of PAP, with promising implications also for other diseases in which macrophages play an important role. Thus, we here summarize the latest insights into the various forms of PAP and introduce new pre-clinical work which is currently conducted in the framework of PAP, introducing new therapies for children and adults who still suffer from this severe, potentially life-threatening disease.

Inhaled recombinant GM-CSF reduces the need for whole lung lavage and improves gas exchange in autoimmune pulmonary alveolar proteinosis patients

RATIONALE

Whole lung lavage (WLL) is a widely accepted palliative treatment for autoimmune pulmonary alveolar proteinosis (aPAP) but does not correct myeloid cell dysfunction or reverse the pathological accumulation of surfactant. In contrast, inhaled recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF) is a promising pharmacological approach that restores alveolar macrophage functions including surfactant clearance. Here, we evaluate WLL followed by inhaled rGM-CSF (sargramostim) as therapy of aPAP.

METHODS

18 patients with moderate-to-severe aPAP were enrolled, received baseline WLL, were randomised into either the rGM-CSF group (receiving inhaled sargramostim) or control group (no scheduled therapy) and followed for 30 months after the baseline WLL. Outcome measures included additional unscheduled "rescue" WLL for disease progression, assessment of arterial blood gases, pulmonary function, computed tomography, health status, biomarkers and adverse events. Patients requiring rescue WLL were considered to have failed their assigned intervention group.

RESULTS

The primary end-point of time to first rescue WLL was longer in rGM-CSF-treated patients than controls (30 versus 18 months, n=9 per group, p=0.0078). Seven control patients (78%) and only one rGM-CSF-treated patient (11%) required rescue WLL, demonstrating a 7-fold increase in relative risk (p=0.015). Compared to controls, rGM-CSF-treated patients also had greater improvement in peripheral arterial oxygen tension, alveolar-arterial oxygen tension difference, diffusing capacity of the lungs for carbon monoxide and aPAP biomarkers. One patient from each group withdrew for personal reasons. No serious adverse events were reported.

CONCLUSIONS

This long-term, prospective, randomised trial demonstrated inhaled sargramostim following WLL reduced the requirement for WLL, improved lung function and was safe in aPAP patients. WLL plus inhaled sargramostim may be useful as combined therapy for aPAP.

Whole lung lavage decreases physiological dead space in patients with pulmonary alveolar proteinosis: two case reports

BACKGROUND

Pulmonary alveolar proteinosis (PAP) is a rare disease characterized by progressive accumulation of the alveolar surfactant. Whole lung lavage (WLL) using a high volume of warmed saline remains the standard therapy. However, no established bedside monitoring tool can evaluate the physiological effect of WLL in the perioperative period. Indirect calorimetry, which is generally used to measure resting energy expenditure, can detect carbon dioxide (CO2) production and mixed-expired partial pressure of CO2 breath by breath. In this physiological study, we calculated CO2 elimination per breath (VTCO2,br) and Enghoff's dead space using indirect calorimetry and measured the extravascular lung water index to reveal the effect of WLL.

CASE PRESENTATION

We measured VTCO2,br, Enghoff's dead space, and the extravascular lung water and cardiac indices before and after WLL to assess the reduction in shunt by washing out the surfactant. A total of four WLLs were performed in two PAP patients. The first case involved an Asian 62-year-old man who presented with a 3-month history of dyspnea on exertion. The second case involved an Asian 48-year-old woman with no symptoms. VTCO2,br increased, and the Enghoff's dead space decreased at 12 h following WLL. An increase in the extravascular lung water was detected immediately following WLL, leading to a transient increase in Enghoff's dead space.

CONCLUSION

WLL can increase efficient alveolar ventilation by washing out the accumulated surfactant. However, the lavage fluid may be absorbed into the lung tissues immediately after WLL and result in an increase in the extravascular lung water.

Alveolar macrophages in pulmonary alveolar proteinosis: origin, function, and therapeutic strategies

Pulmonary alveolar proteinosis (PAP) is a rare pulmonary disorder that is characterized by the abnormal accumulation of surfactant within the alveoli. Alveolar macrophages (AMs) have been identified as playing a pivotal role in the pathogenesis of PAP. In most of PAP cases, the disease is triggered by impaired cholesterol clearance in AMs that depend on granulocyte-macrophage colony-stimulating factor (GM-CSF), resulting in defective alveolar surfactant clearance and disruption of pulmonary homeostasis. Currently, novel pathogenesis-based therapies are being developed that target the GM-CSF signaling, cholesterol homeostasis, and immune modulation of AMs. In this review, we summarize the origin and functional role of AMs in PAP, as well as the latest therapeutic strategies aimed at addressing this disease. Our goal is to provide new perspectives and insights into the pathogenesis of PAP, and thereby identify promising new treatments for this disease.

Association between one-session bilateral whole-lung lavage and periprocedural complications in patients with pulmonary alveolar proteinosis: a retrospective cohort study

BACKGROUND

Whole lung lavage (WLL) has been recognized as the most effective therapy of severe pulmonary alveolar proteinosis (PAP). Most centers perform the lavage of each lung in two sessions under general anesthesia at an interval of several days to weeks. Compared with two-session WLL, one-session bilateral sequential WLL only requires general anesthesia once. However, the safety of one-session WLL in PAP patients has not been assessed by large cohort studies. In this study, we aimed to investigate the association between the mode of WLL procedure (one-session or two-session) and the risk of periprocedural complications in PAP patients.

METHODS

In this single-center retrospective cohort study, we included adult patients who were diagnosed as PAP and had undergone WLL procedures under general anesthesia from 2000 to 2022. Patients requiring extra-corporeal oxygenation during WLL were excluded. Since some patients received multiple WLL procedures, we considered each procedure in one-session or two-session group as a unique unit in our analysis. The primary outcome was the occurrence of any complications during hospitalization, including termination of WLL procedure due to fluid leakage or refractory hypoxemia, bronchospasm, delayed endotracheal extubation, cardiovascular event, pneumothorax, and fever.

RESULTS

We included a total of 175 WLL procedures (118 patients), with 48 in the two-session group and 127 in the one-session group. Periprocedural complications occurred in 17 (35.4%) and 39 (30.7%) procedures in the two-session and the one-session groups, respectively. The risk of periprocedural complications did not differ significantly between groups, after adjusting the unbalanced confounders in a multivariable model (odds ratio 0.95, 95% confidence interval 0.34 to 2.69, P 0.929) or by inverse probability of treatment weighting (odds ratio 0.70, 95% confidence interval 0.30 to 1.54, P 0.379). Compared with the two-session WLL group, the one-session WLL group had a shorter postprocedural length of hospitalization and comparable decrease in alveolar-arterial oxygen tension gradient from baseline.

CONCLUSIONS

One-session bilateral WLL was not associated with an increased risk of periprocedural complications compared with two-session WLL in PAP patients. Experienced physicians may consider performing one-session WLL in view of the comparable safety and efficacy and potential advantages of saving time.

The world of rare interstitial lung diseases

The world of rare interstitial lung diseases (ILDs) is diverse and complex. Diagnosis and therapy usually pose challenges. This review describes a selection of rare and ultrarare ILDs including pulmonary alveolar proteinosis, pulmonary alveolar microlithiasis and pleuroparenchymal fibroelastosis. In addition, monogenic ILDs or ILDs in congenital syndromes and various multiple cystic lung diseases will be discussed. All these conditions are part of the scope of the European Reference Network on rare respiratory diseases (ERN-LUNG). Epidemiology, pathogenesis, diagnostics and treatment of each disease are presented.

[Interstitial lung diseases in children of genetic origin]

Interstitial lung diseases in children of genetic origin. Interstitial lung disease (ILD) in children (chILD) encompasses a heterogeneous group of rare respiratory disorders, most of which are chronic and severe. In more and more of these cases, a genetic cause has been identified. As of now, the main mutations have been localized in the genes encoding the surfactant proteins (SP)-C (SFTPC), SP-B (SFTPB), their transporter ATP-binding cassette, family 1, member 3 (ABCA3), transcription factor NK2 homeobox 1 (NKX2-1) and, more rarely, SP-A1 (SFTPA1) or SP-A2 (SFTPA2). Pediatric pulmonary alveolar proteinosis (PAP) is associated with mutations in CSF2RA, CSF2RB, and MARS; more recently, mutations in STING1 and COPA have been associated with specific auto-inflammatory disorders including ILD manifestations. The relationships between the molecular abnormalities and the phenotypic expressions generally remain poorly understood. In the coming years, it is expected that newly identified molecular defects will help to more accurately predict disease courses and to produce individualized targeted therapies.

Characteristics of hospital admissions for pulmonary alveolar proteinosis: analysis of the nationwide inpatient sample (2012-2014)

BACKGROUND

Pulmonary alveolar proteinosis (PAP) is a rare clinical syndrome involving the accumulation of lipid-rich proteinaceous material in the alveoli. There is a paucity of published studies on this condition. To better characterize the demographics, complication rates, mortality, and healthcare costs of patients hospitalized for PAP in the United States, a secondary analysis on the Hospital Cost and Utilization Project's Nationwide Inpatient Sample (NIS) was performed on patients admitted from 2012 to 2014 with a diagnosis of pulmonary alveolar proteinosis.

METHODS

Using the NIS database, a secondary analysis was performed on 500 admissions with the diagnosis "pulmonary alveolar proteinosis." The clinical variables and outcome measures extracted were: patient demographics, hospital costs, length of stay, frequency of admissions, and inpatient mortality rate.

RESULTS

Among a weighted estimate of 500 hospital admissions from 2012 to 2014, the number of PAP admissions averaged 4.7 per million. The population was predominantly male (55%) with a mean age of 41.45 (CI 38.3-44.5) from all socioeconomic levels. Inpatient mortality was calculated to be 5%, which may result from the fact that the majority of admitted patients had few or no comorbid conditions (CCI 0.72). The most common procedure performed during admission was a bronchoalveolar lavage. Mean length of stay was 6.2 days (CI 3.9-8.5) and average cost of admission was $29,932.20 (CI 13,739-46,124). Of note, 50% of these admissions were considered "elective."

CONCLUSIONS

Demographics of patients with PAP who have been hospitalized in the United States are similar to previously reported demographics from prior patient cohorts, specifically a male predominance and a mean age in the 40 s. The inpatient mortality rate of 5% we found is consistent with prior studies demonstrating good disease-specific survival rates. Notably, the cost per admission and overall annual cost associated with PAP hospitalization was calculated to be $29932.20 and $5 million respectively. This reflects the high economic cost associated with hospitalization of PAP patients, and provokes thought about ways to make treatment more cost-effective.

Progress in Respiratory Gene Therapy

The prospect of gene therapy for inherited and acquired respiratory disease has energized the research community since the 1980s, with cystic fibrosis, as a monogenic disorder, driving early efforts to develop effective strategies. The fact that there are still no approved gene therapy products for the lung, despite many early phase clinical trials, illustrates the scale of the challenge: In the 1990s, first-generation non-viral and viral vector systems demonstrated proof-of-concept but low efficacy. Since then, there has been steady progress toward improved vectors with the capacity to overcome at least some of the formidable barriers presented by the lung. In addition, the inclusion of features such as codon optimization and promoters providing long-term expression have improved the expression characteristics of therapeutic transgenes. Early approaches were based on gene addition, where a new DNA copy of a gene is introduced to complement a genetic mutation: however, the advent of RNA-based products that can directly express a therapeutic protein or manipulate gene expression, together with the expanding range of tools for gene editing, has stimulated the development of alternative approaches. This review discusses the range of vector systems being evaluated for lung delivery; the variety of cargoes they deliver, including DNA, antisense oligonucleotides, messenger RNA (mRNA), small interfering RNA (siRNA), and peptide nucleic acids; and exemplifies progress in selected respiratory disease indications.

Pulmonary Alveolar Proteinosis and Pregnancy: A Review of the Literature and Case Presentation

Pulmonary Alveolar Proteinosis (PAP) is a rare, usually autoimmune, disease, where surfactant accumulates within alveoli due to decreased clearance, causing dyspnea and hypoxemia. The disease is even more rare in pregnancy; nevertheless, it has been reported in pregnant women and can even appear for the first time during pregnancy as an asthma-like illness. Therefore, awareness is important. Similarly to many autoimmune diseases, it can worsen during pregnancy and postpartum, causing maternal and fetal/neonatal complications. This paper offers a narrative literature review of PAP and pregnancy, while illustrating a case of a pregnant patient with known PAP who developed preeclampsia in the third trimester but had an overall fortunate maternal and neonatal outcome.

How We Do It: Whole Lung Lavage

Pulmonary alveolar proteinosis (PAP) is a rare pulmonary disorder characterized by the accumulation of surfactant in the alveolar spaces resulting in hypoxemic respiratory failure. Whole lung lavage (WLL), the preferred treatment for PAP, physically removes the lipoproteinaceous material from the alveolar spaces. Since its initial description in 1963, the WLL procedure has undergone various modifications. However, the procedure has not been standardized yet. After securing a double lumen endotracheal tube, we perform WLL under general anesthesia. One lung is ventilated, while the other is lavaged using one-liter aliquots of pre-warmed saline. We use gravity-assisted drainage of the lavaged lung after each cycle till the milky white and opaque fluid becomes clear (usually 15-20 cycles). Herein, we describe the step-by-step procedure, precautions, and monitoring of WLL. We also provide videos demonstrating one-lung ventilation and bronchoscopic confirmation of lung isolation.

Correction of a chronic pulmonary disease through lentiviral vector-mediated protein expression

We developed a novel lentiviral vector, pseudotyped with the F and HN proteins from Sendai virus (rSIV.F/HN), that produces long-lasting, high-efficiency transduction of the respiratory epithelium. Here we addressed whether this platform technology can secrete sufficient levels of a therapeutic protein into the lungs to ameliorate a fatal pulmonary disease as an example of its translational capability. Pulmonary alveolar proteinosis (PAP) results from alveolar granulocyte-macrophage colony-stimulating factor (GM-CSF) insufficiency, resulting in abnormal surfactant homeostasis and consequent ventilatory problems. Lungs of GM-CSF knockout mice were transduced with a single dose of rSIV.F/HN-expressing murine GM-CSF (mGM-CSF; 1e5-92e7 transduction units [TU]/mouse); mGM-CSF expression was dose related and persisted for at least 11 months. PAP disease biomarkers were rapidly and persistently corrected, but we noted a narrow toxicity/efficacy window. rSIV.F/HN may be a useful platform technology to deliver therapeutic proteins for lung diseases requiring long-lasting and stable expression of secreted proteins.

Autoimmune Pulmonary Alveolar Proteinosis

Autoimmune pulmonary alveolar proteinosis (PAP) is a rare disease characterized by myeloid cell dysfunction, abnormal pulmonary surfactant accumulation, and innate immune deficiency. It has a prevalence of 7-10 per million; occurs in individuals of all races, geographic regions, sex, and socioeconomic status; and accounts for 90% of all patients with PAP syndrome. The most common presentation is dyspnea of insidious onset with or without cough, production of scant white and frothy sputum, and diffuse radiographic infiltrates in a previously healthy adult, but it can also occur in children as young as 3 years. Digital clubbing, fever, and hemoptysis are not typical, and the latter two indicate that intercurrent infection may be present. Low prevalence and nonspecific clinical, radiological, and laboratory findings commonly lead to misdiagnosis as pneumonia and substantially delay an accurate diagnosis. The clinical course, although variable, usually includes progressive hypoxemic respiratory insufficiency and, in some patients, secondary infections, pulmonary fibrosis, respiratory failure, and death. Two decades of research have raised autoimmune PAP from obscurity to a paradigm of molecular pathogenesis-based diagnostic and therapeutic development. Pathogenesis is driven by GM-CSF (granulocyte/macrophage colony-stimulating factor) autoantibodies, which are present at high concentrations in blood and tissues and form the basis of an accurate, commercially available diagnostic blood test with sensitivity and specificity of 100%. Although whole-lung lavage remains the first-line therapy, inhaled GM-CSF is a promising pharmacotherapeutic approach demonstrated in well-controlled trials to be safe, well tolerated, and efficacious. Research has established GM-CSF as a pulmonary regulatory molecule critical to surfactant homeostasis, alveolar stability, lung function, and host defense.

Lung injury induced by different negative suction pressure in patients with pneumoconiosis undergoing whole lung lavage

Background

Pneumoconiosis is a diffuse interstitial fibronodular lung disease, which is caused by the inhalation of crystalline silica. Whole lung lavage (WLL) is a therapeutic procedure used to treat pneumoconiosis. This study is to compare the effects of different negative pressure suction on lung injury in patients with pneumoconiosis undergoing WLL.

Materials and methods

A prospective study was conducted with 24 consecutively pneumoconiosis patients who underwent WLL from March 2020 to July 2020 at Emergency General Hospital, China. The patients were divided into two groups: high negative suction pressure group (group H, n = 13, negative suction pressure of 300–400 mmHg) and low negative suction pressure group (group L, n = 11, negative suction pressure of 40–50 mmHg). The arterial blood gas, lung function, lavage data, oxidative stress, and inflammatory responses to access lung injury were monitored.

Results

Compared with those of group H, the right and left lung residual were significantly increased in the group L (P = 0.04, P = 0.01). Potential of hydrogen (pH), arterial partial pressure of oxygen (PaO₂), arterial partial pressure of carbon dioxide (PaCO₂), lactic acid (LAC) and glucose (GLU) varied from point to point in time (P < 0.01, respectively). There was statistical difference in the trend of superoxide dismutase (SOD) and interleukin-10 (IL-10) over time between the two groups (P < 0.01, P = 0.02). In comparison with the group H, the levels of IL-10 (P = 0.01) and SOD (P < 0.01) in WLL fluid were significantly increased in the group L. There was no statistical difference in the trend of maximal volumtary ventilation (MVV), forced vital capacity (FVC), forced expiratory volume in one second (FEV1%), residual volume (RV), residual volume/total lung capacity (RV/TLC), carbon monoxide dispersion factor (DLCO%), forced expiratory volume in one second/ forced vital capacity (FEV1/FVC%) over time between the two groups (P > 0.05, respectively).

Conclusion

Low negative suction pressure has the potential benefit to reduce lung injury in patients with pneumoconiosis undergoing WLL, although it can lead to increased residual lavage fluid. Despite differing suction strategies, pulmonary function parameters including FEV1%, RV and DLCO% became worse than before WLL.

Trial Registration Chinese Clinical Trial registration number ChiCTR2000031024, 21/03/2020.

A Bibliometric Analysis of Pulmonary Alveolar Proteinosis From 2001 to 2021

Background

Pulmonary alveolar proteinosis (PAP) is a rare syndrome first described by Rosen et al. in 1958. Despite our considerably evolved understanding of PAP over the past decades, no bibliometric studies have been reported on this field. We aimed to analyze and visualize the research hotspots and current trends of the PAP research field using a bibliometric analysis to help understand the future development of basic and clinical research.

Methods

The literature regarding PAP was culled from the Web of Science Core Collection (WoSCC) database. Data were extracted from the relevant articles and visually analyzed using CiteSpace and VOSviewer software.

Results

Nine hundred and nine qualifying articles were included in the analysis. Publications regarding PAP increased over time. These articles mainly come from 407 institutions of 57 countries. The leading countries were the USA and Japan. University of Cincinnati (USA) and Niigata University (Japan) featured the highest number of publications among all institutions. Bruce C Trapnell exerts a significant publication impact and has made the most outstanding contributions in the field of PAP. American Journal of Physiology-Lung Cellular and Molecular Physiology was the journal with the most publications, and American Journal of Respiratory and Critical Care Medicine was the most commonly cited journal. All the top 5 co-cited journals belong to Q1. Keyword citation bursts revealed that inflammation, deficiency, tissue resident macrophage, classification, autoimmune pulmonary alveolar proteinosis, sarcoidosis, gm csf, high resolution ct, and fetal monocyte were the emerging research hotspots.

Conclusion

Research on PAP is prosperous. International cooperation is also expected to deepen and strengthen in the future. Our results indicated that the etiology and pathogenesis of PAP, current and emerging therapies, especially the novel pathogenesis-based options will remain research hotspots in the future.

A mini-whole lung lavage to treat autoimmune pulmonary alveolar proteinosis (PAP)

Background

PAP is an ultra-rare respiratory syndrome characterized by the accumulation of surfactant within the alveoli. Whole lung lavage (WLL) is the current standard of care of PAP, however it is not a standardized procedure and the total amount of fluid used to wash each lung is still debated. Considering ICU hospitalization associated risks, a “mini-WLL” with anticipated manual clapping and reduced total infusion volume and has been proposed in our center.

The aim of the study is to retrospectively analyze the efficacy of mini-WLL compared to standard WLL at the Pavia center.

Methods

13 autoimmune PAP patients eligible for WLL were included: 7 patients were admitted to mini-WLL (9 L total infusion volume for each lung) and 6 patients underwent standard WLL (14 L of infusion volume). Functional data (VC%, FVC%, TLC%, DLCO%) and alveolar-arterial gradient values (A-aO2) were collected at the baseline and 1, 3, 6, 12, 18 months after the procedure.

Results

A statistically significant improvement of VC% (p = 0.013, 95%CI 3.49–30.19), FVC% (p = 0.016, 95%CI 3.37–32.09), TLC% (p = 0.001, 95%CI 7.38–30.34) was observed in the mini-WLL group in comparison with the standard WLL group, while no significant difference in DLCO% and A-aO2 mean values were reported.

Conclusion

Mini-WLL has demonstrated higher efficacy in ameliorating lung volumes, suggesting that a lower infusion volume is sufficient to remove the surfactant accumulation and possibly allows a reduced mechanical insult of the bronchi walls and the alveoli. However, no statistically significant differences were found in terms of DLCO% and Aa-O2.

Association between the IL-6 polymorphisms and coal workers’ pneumoconiosis in a Chinese Hui population

Objective

To determine whether polymorphisms in IL-6 and IL-12 contribute to the etiology of coal workers’ pneumoconiosis (CWP) in a Chinese Hui population, and to evaluate the efficacy and safety of high frequency oscillatory ventilation (HFOV) in the treatment of CWP.

Introduction

Genes and the environments interplay in the development of CWP, and the association between the potential functional polymorphisms in many genes and CWP have been reported.

Methods

We genotyped the IL-6-634C/G (rs1800796) and IL-12B-1188A/C (rs3212227) polymorphisms in a case-control study including 160 CWP patients and 150 dust-exposed control subjects of Chinese Hui population, and analyzed the associations between these genetic variants and CWP risk. We also evaluated the efficacy and safety of HFOV for whole lung lavage (WLL) in the treatment of CWP.

Results

Carrying the C allele of IL-6-634C/G (rs1800796) was associated with decreased risk of CWP ( p < 0.05). No significant differences in allele or genotype frequencies of IL-12B-1188A/C was found between the CWP cases and control subjects ( p > 0.05). Compared with CWP patients with routine WLL, CWP patients received HFOV showed better pulmonary functions. HFOV treatment also yield a significant higher efficient rate (97.50%) than WLL treatment (81.25%, p = 0.001). CWP patients receiving HFOV and WLL treatment both showed significantly increased serum contents of Clara cell protein 16 (CC16) and superoxide dismutase (SOD), and decreased serum contents of serum malonaldehyde (MDA). While the increasing of CC16 and SOD, and decreasing of MDA in patients receiving HFOV was more noticeable than patients receiving WLL.

Conclusions

Taking together, the −634C/G polymorphisms in IL-6 play a role in the etiology of CWP. HFOV, when applied in CWP patients, significant improves their pulmonary functions.

Anesthetic management during whole-lung lavage using lung ultrasound in a patient with pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) is an uncommon disease characterized by progressive accumulation of lipoprotein material in the lungs due to impaired surfactant clearance. Whole-lung lavage (WLL) is the current standard treatment and consists of sequential lavage of each lung to mechanically remove the residual material from the alveoli. Although WLL is considered safe, unexpected complications can occur. Moreover, due to the rarity of the disease itself, this procedure is unknown to many physicians, and management of intraoperative complications can be challenging for anesthesiologists. Lung ultrasound (LUS) provides reliable and valuable information for detecting perioperative pulmonary complications and, in particular, quantitation of lung water content. There have been reports on monitoring the different stages of controlled deaeration of the non-ventilated lung during WLL using LUS. However, it has been limited to non-ventilated lungs. Therefore, we report the use of LUS in WLL to proactively detect pulmonary edema in the ventilated lung and implement a safe and effective anesthesia strategy. Given the limited diagnostic tools available to anesthesiologists in the operating room, LUS is a reliable, fast, and noninvasive method for identifying perioperative pulmonary complications in patients with PAP undergoing WLL.

Update on Diagnosis and Treatment of Adult Pulmonary Alveolar Proteinosis

Pulmonary alveolar proteinosis (PAP) is a rare pulmonary surfactant homeostasis disorder resulting in buildup of lipo-proteinaceous material within the alveoli. PAP is classified as primary (autoimmune and hereditary), secondary, congenital and unclassifiable type based on the underlying pathogenesis. PAP has an insidious onset and can, in some cases, progress to severe respiratory failure. Diagnosis is often secured with bronchoalveolar lavage in the setting of classic imaging findings. Recent insights into genetic alterations and autoimmune mechanisms have provided newer diagnostics and treatment options. In this review, we discuss the etiopathogenesis, diagnosis and treatment options available and emerging for PAP.

Increased Efficacy of Whole Lung Lavage Treatment in Alveolar Proteinosis Using a New Modified Lavage Technique

BACKGROUND

Autoimmune pulmonary alveolar proteinosis is an ultra-rare pulmonary disease. Whole lung lavage (WLL) is considered the gold standard therapy. We report a protocol for a new modified lavage technique (nMLT) in which controlled repetitive manual hyperinflation (MH) and intermittent chest percussion are used to enhance WLL efficacy.

METHODS

We included all subjects with autoimmune pulmonary alveolar proteinosis treated with nMLT between 2013 and 2018. nMLT consisted of repetitive MH with intermittent chest percussion every third wash. We reported: instilled volume, protein concentration, and optical density using spectrophotometry. Pulmonary function (FVC %predicted and DLCO %predicted) at start of nMLT was recorded. Data are displayed as mean (±SD), median [interquartile range], or number (%). Comparisons within individuals were made using Students t test.

RESULTS

We included 11 subjects (64% male) in whom a total of 67 nMLTs were performed. One nMLT consisted of 15 [12-18] washes. Protein removal was 9.80 [7.52-12.66] g per nMLT. After the first, second, and third cycle of 3 washes, 56% [49% to 61%], 81% [77% to 84%], and 91% [88% to 94%] of the final protein yield was removed, respectively. Optical density was measured 116 times and increased from 1.13 (±0.52) to 1.31 (±0.52) after MH (P<0.001).

CONCLUSION

Efficacy of WLL seems to be enhanced by applying MH every 3 washes. Our technique of WLL with nMLT could be used to increase the amount of protein recruited while instilling the lung with the smallest volume of fluid as possible.

Pulmonary Alveolar Proteinosis in Children: Diagnosis and Treatment Outcomes

Background

Pulmonary Alveolar Proteinosis (PAP) is an uncommon pulmonary disease characterized by the accumulation of surfactant composed of proteins and lipids due to disruption of surfactant clearance by alveolar macrophages. The current standard treatment is lung lavage. There are no specific criteria for lavage, but in case of observing these signs it is recommended to perform lavage for the patient: progressive respiratory failure, no labored breathing at rest, and drop in oxygen level during activity (>5%).

Materials and Methods

In this study, patients with PAP admitted to Pediatric ward of Masih Daneshvari Hospital were studied. The required data were collected including the patient's demographic data, clinical signs and radiographic data, the number of admissions, the age of diagnosis, detection and treatment methods, number of lavage, current condition of the patient, and in case of death, the cause of death.

Results

In this study, 17 patients with PAP who were admitted during the past 15 years were examined; among which 7 patients were boys (41.2%) and 10 were girls (58.8%). The mean age of population was 11.79±7.21 years. Transbronchial Lung Biopsy (TBLB) (47.1%) and open lung biopsy (52.9%) were used for diagnosis of patients. Lung lavage was used to treat patients, 15 of whom were treated by this method. Five of the patients died because of their serious conditions.

Conclusion

Therapy method in the present study was lavage for both lungs, and it was performed for all patients except for two patients due to their anatomical complications. This method is still considered as the gold standard for PAP. Considering the findings from previous studies and the present study, it seems that Whole Lung Lavage (WLL) was fruitful for patients who had the indication for using this therapy and it played a significant role in improving the prognosis of patients. Besides, it is recommended to do follow-up regularly in order to have more therapeutic efficacy and increased patient longevity.

Pediatric bronchoscopy: recent advances and clinical challenges

Introduction: During the last 40 years equipment has been improved with smaller instruments and sufficient size working channels. This has ensured that bronchoscopy offers therapeutic and interventional options.Areas covered: We provide a review of recent advances and clinical challenges in pediatric bronchoscopy. This includes single-use bronchoscopes, endobronchial ultrasound, and cryoprobe. Bronchoscopy in persistent preschool wheezing and asthma is included. The indications for interventional bronchoscopy have amplified and included balloon dilatation, endoscopic intubation, the use of airway stents, whole lung lavage, closing of fistulas and air leak, as well as an update on removal of foreign bodies. Others include the use of laser and microdebrider in airway surgery. Experience with bronchoscope during the COVID-19 pandemic has been included in this review. PubMed was searched for articles on pediatric bronchoscopy, including rigid bronchoscopy as well as interventional bronchoscopy with a focus on reviewing literature in the past 5 years.Expert opinion: As the proficiency of pediatric interventional pulmonologists continues to grow more interventions are being performed. There is a scarcity of published evidence in this field. Courses for pediatric interventional bronchoscopy need to be developed. The COVID-19 experience resulted in safer bronchoscopy practice for all involved.

The efficacy and safety of therapeutic lung lavage for exogenous lipoid pneumonia: A systematic review

INTRODUCTION AND OBJECTIVES

Exogenous lipoid pneumonia (ELP) is a lung inflammatory disease with low prevalence and has the feature of external lipid substances presented in the alveoli. Therapeutic lung lavage (segmental bronchoalveolar lavage and whole lung lavage) has been gradually recognized as an important therapy for the disease. There was no comprehensive summary on its efficacy and safety.

METHODS

We searched PubMed, Embase, Cochrane Library, CNKI, Wanfang Database, clinicaltrials.gov, and the references of included studies. After study selection, data extraction and quality assessment, we performed a qualitative description of current data.

RESULTS

We included 90 ELP patients from 25 case reports and 8 case series studies. Eighty-four (93.3%) patients received segmental bronchoalveolar lavage and six (6.7%) patients received whole lung lavage. Eighty-seven (96.7%) patients got clinical improvement after lavages, while three (3.3%) patients had no improvement and eventually died. The follow-up status was reported in 29 patients, of whom 24 patients remained well without any use of drugs and 4 patients remained well with some periods of corticosteroids. One patient endured recurrence. The radiological change was reported in 72 patients, of whom 41 (56.9%) patients had full resolution until the last follow-up. Two studies reported acute pulmonary edema and transient hypoxemia during lavages.

CONCLUSIONS

Therapeutic lung lavage might be an effective and safe therapy with long-term benefits for ELP. Current studies were all case reports and case series with relatively high risk of bias. Prospective controlled studies are needed to explore the actual efficacy, safety, individualized indications, and optimized treatment procedures of therapeutic lung lavage for ELP.

Whole-Lung Lavage-a Narrative Review of Anesthetic Management

Pulmonary alveolar proteinosis is a rare disease characterized by progressive accumulation of lipoprotein material in the alveoli as a result of a dysfunction in surfactant clearance. The whole-lung lavage procedure is considered the current standard of care and consists of the sequential lavage of both lungs for mechanical removal of residual material in the alveoli. However, a lack of standardization has resulted in different procedural techniques among institutions. Even though whole-lung lavage is considered to be a safe procedure, unforeseen complications might occur, and proper knowledge of physiologic implications may allow clinicians to establish the appropriate therapy. This review provides an insight into the underlying physiology of the disease, the technical details of the procedure from an anesthesiologist's perspective, and discussion of potential intraoperative complications.

Inhaled Molgramostim Therapy in Autoimmune Pulmonary Alveolar Proteinosis

BACKGROUND

Autoimmune pulmonary alveolar proteinosis (aPAP) is a rare disease characterized by progressive surfactant accumulation and hypoxemia. It is caused by disruption of granulocyte-macrophage colony-stimulating factor (GM-CSF) signaling, which pulmonary alveolar macrophages require to clear surfactant. Recently, inhaled GM-CSF was shown to improve the partial pressure of arterial oxygen in patients with aPAP.

METHODS

In a double-blind, placebo-controlled, three-group trial, we randomly assigned patients with aPAP to receive the recombinant GM-CSF molgramostim (300 μg once daily by inhalation), either continuously or intermittently (every other week), or matching placebo. The 24-week intervention period was followed by an open-label treatment-extension period. The primary end point was the change from baseline in the alveolar-arterial difference in oxygen concentration (A-aDo₂) at week 24.

RESULTS

In total, 138 patients underwent randomization; 46 were assigned to receive continuous molgramostim, 45 to receive intermittent molgramostim, and 47 to receive placebo. Invalid A-aDo₂ data for 4 patients (1 in each molgramostim group and 2 in the placebo group) who received nasal oxygen therapy during arterial blood gas measurement were replaced by means of imputation. For the primary end point - the change from baseline in the A-aDo₂ at week 24 - improvement was greater among patients receiving continuous molgramostim than among those receiving placebo (-12.8 mm Hg vs. -6.6 mm Hg; estimated treatment difference, -6.2 mm Hg; P = 0.03 by comparison of least-squares means). Patients receiving continuous molgramostim also had greater improvement than those receiving placebo for secondary end points, including the change from baseline in the St. George's Respiratory Questionnaire total score at week 24 (-12.4 points vs. -5.1 points; estimated treatment difference, -7.4 points; P = 0.01 by comparison of least-squares means). For multiple end points, improvement was greater with continuous molgramostim than with intermittent molgramostim. The percentages of patients with adverse events and serious adverse events were similar in the three groups, except for the percentage of patients with chest pain, which was higher in the continuous-molgramostim group.

CONCLUSIONS

In patients with aPAP, daily administration of inhaled molgramostim resulted in greater improvements in pulmonary gas transfer and functional health status than placebo, with similar rates of adverse events. (Funded by Savara Pharmaceuticals; IMPALA ClinicalTrials.gov number, NCT02702180.).

Total alveolar lavage with oxygen fine bubble dispersion directly improves lipopolysaccharide-induced acute respiratory distress syndrome of rats

Severe respiratory disorder induced by pulmonary inflammation is one of the causes of acute respiratory distress syndrome, which still has high mortality. It is crucial to remove causative substances and inflammatory mediators early in order to inhibit the progression of pulmonary inflammation. Total alveolar lavage (TAL) may avert the inflammatory response by eliminating causative substances in certain inflammatory lung diseases. We developed an efficient TAL system and examined the efficacy of short-term TAL treatment performed for acute lung injury models of rats. In the first experiment with a severe lung injury model, 15 rats were divided into 3 groups: sham group, mechanical gas ventilation (MGV) treatment group, and TAL treatment group. The treatments were conducted for 5 min, 20 min after the provocation of inflammation. Two days after treatment, the TAL and MGV treatment groups exhibited significant differences in blood oxygen levels, mean arterial pressure, weight-loss ratio, and inflammatory cytokine levels in the lungs. In contrast, almost no differences were observed between the TAL treatment and sham groups. In the second experiment with a lethal lung injury model, the TAL treatment dramatically improved the survival rate of the rats compared to the MGV treatment groups (p = 0.0079). Histopathological analysis confirmed pronounced differences in neutrophil accumulation and thickening of the interstitial membrane between the TAL and MGV treatment groups in both experiments. These results indicate that as little as 5 min of TAL treatment can protect rats from acute lung injury by removing causative substances from the lungs.

Nicotine induces apoptosis through exacerbation of blocked alveolar macrophage autophagic degradation in silicosis

Silica dust mainly attacks alveolar macrophages (AMs). The apoptosis of AMs is correlated with the progress of silicosis. Our previous study showed that autophagic degradation was blocked in AMs from silicosis patients. However, the effects of nicotine on AM autophagy and apoptosis in silicosis are unknown. In this study, we collected AMs from twenty male workers exposed to silica and divided them into observer and silicosis patient groups, according to the tuberous pathological changes observed by X-ray. The AMs from both groups were exposed to nicotine. We found increased levels of LC3, p62, and cleaved caspase-3, decreased levels of LAMP2, and damaged lysosomes after nicotine stimulation of the AMs from both groups. We also found that the autophagy inhibitor 3-methyladenine (3MA) inhibited nicotine-induced apoptosis in the AMs. Furthermore, 3MA reversed both the nicotine-induced decrease in Bcl-2 and the increase in Bax in both groups. These results suggest that nicotine may induce apoptosis by blocking AM autophagic degradation in human silicosis.

Pulmonary alveolar proteinosis: from classification to therapy

Pulmonary alveolar proteinosis (PAP) is a rare respiratory syndrome characterised by the accumulation of surfactant lipoproteins within the alveoli. According to various pathogenetic mechanisms and aetiologies, PAP is classified as primary, secondary or congenital. Primary PAP is led by a granulocyte–macrophage colony-stimulating factor (GM-CSF) signalling disruption; the autoimmune form is driven by the presence of anti GM-CSF autoantibodies and represents 90% of all the PAP cases; and the hereditary form is the result of mutations in genes encoding GM-CSF receptor. Secondary PAP is associated with various diseases causing a reduction in function and/or number of alveolar macrophages. Congenital PAP emerges as a consequence of corrupted surfactant production, due to mutations in surfactant proteins or lipid transporter, or mutations affecting lung development. The clinical manifestations are various, ranging from insidious onset to acute or progressive respiratory failure, including premature death within the first days of life in neonates with congenital surfactant production disorders. The diagnostic workup includes clinical and radiological assessment (respiratory function test, high-resolution chest computed tomography), laboratory tests (anti-GM-CSF autoantibodies dosage, GM-CSF serum level and GM-CSF signalling test), and genetic tests. Whole-lung lavage is the current gold standard of care of PAP; however, the therapeutic approach depends on the pathogenic form and disease severity, including GM-CSF augmentation strategies in autoimmune PAP and other promising new treatments.

A concise educational review of pulmonary alveolar proteinosis (PAP), a rare respiratory syndrome with various and heterogeneous aetiologies, caused by the impairment of pulmonary surfactant clearance or by abnormal surfactant productionhttps://bit.ly/3aFpQm9

Interstitial lung diseases in children

Interstitial lung disease (ILD) in children (chILD) is a heterogeneous group of rare respiratory disorders that are mostly chronic and associated with high morbidity and mortality. The pathogenesis of the various chILD is complex and the diseases share common features of inflammatory and fibrotic changes of the lung parenchyma that impair gas exchanges. The etiologies of chILD are numerous. In this review, we chose to classify them as ILD related to exposure/environment insults, ILD related to systemic and immunological diseases, ILD related to primary lung parenchyma dysfunctions and ILD specific to infancy. A growing part of the etiologic spectrum of chILD is being attributed to molecular defects. Currently, the main genetic mutations associated with chILD are identified in the surfactant genes SFTPA1, SFTPA2, SFTPB, SFTPC, ABCA3 and NKX2-1. Other genetic contributors include mutations in MARS, CSF2RA and CSF2RB in pulmonary alveolar proteinosis, and mutations in TMEM173 and COPA in specific auto-inflammatory forms of chILD. However, only few genotype-phenotype correlations could be identified so far. Herein, information is provided about the clinical presentation and the diagnosis approach of chILD. Despite improvements in patient management, the therapeutic strategies are still relying mostly on corticosteroids although specific therapies are emerging. Larger longitudinal cohorts of patients are being gathered through ongoing international collaborations to improve disease knowledge and targeted therapies. Thus, it is expected that children with ILD will be able to reach the adulthood transition in a better condition.

How to do whole lung lavage for treatment of pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis is a rare condition characterized by progressive accumulation of surfactant lipoproteins in the alveolar space, leading to poor gas exchange. We describe our technique of whole lung lavage for management of pulmonary alveolar proteinosis.

Effects of one-lung flooding on porcine haemodynamics and gas exchange

Background and aim: We established a porcine model of one-lung flooding (OLF) that can be used for research on the use of ultrasound for lung tumour detection, ultrasound-guided transthoracic needle biopsy, and tumour ablation. However, OLF requires one-lung ventilation (OLV) and eliminates the recruitment strategies of the nonventilated lung. During thoracic surgery, OLV alone can be associated with hypoxia, hypercapnia, and right ventricular overload. Here, we examined whether OLF influences haemodynamics and gas exchange indices during and after OLV/OLF compared with OLV/apnoea and two-lung ventilation (TLV) following deflooding. Methods: Fourteen pigs were included in this study: five were allocated to the control group (CO) and nine were assigned to the OLF group (OLF). Assessments of haemodynamics, gas exchange, and lung sonography were performed after baseline measurements, during OLV/apnoea, OLV/OLF, and after deflooding and TLV. The volume of extravascular lung water was also measured. Results: OLF induced no significant deterioration of oxygenation or ventilation during OLF or after deflooding and TLV. Color-coded duplex sonography of the pulmonary artery in the flooded lung demonstrated an oscillating flow that corresponded to intrapulmonary circulatory arrest. After flooding of the nonventilated lung, the partial pressure of O₂ in the arterial blood increased and the shunt fraction decreased significantly compared to OLV/apnoea conditions. After deflooding and TLV, haemodynamics and gas exchange indices showed no differences compared to the CO group and baseline values, respectively. Conclusions: OLF is safe to use during acute animal experimentation. No clinically relevant deterioration of haemodynamics or gas exchange occurred during or after OLF. Due to the circulatory arrest in the flooded lung, the right-to-left shunt volume in the nonventilated lung was minimized. Survival experiments are necessary to further assess the utility of this method.

Valuable Serum Markers in Pulmonary Alveolar Proteinosis

Objective

Several serum markers were reported to reflect the severity of pulmonary alveolar proteinosis (PAP). The aim of this study is to investigate a reliable and facile marker to access and monitor the clinical course of PAP in a large cohort.

Methods

PAP patients from January 2010 to June 2018 were enrolled. Hospital records were used as data sources. The levels of various serum indicators were detected. We evaluated the correlation between pulmonary function test results and clinical variables.

Results

Diffusion capacity for carbon monoxide (DLCO) level was positively correlated with the level of high-density lipoprotein cholesterol (HDL-C) (P < 0.05) in 122 patients of PAP at baseline. The levels of HDL-C and DLCO significantly increased while carcinoembryonic antigen (CEA), CYFRA21-1, neuron-specific enolase (NSE), and lactic dehydrogenase (LDH) levels decreased six months after granulocyte-macrophage colony-stimulating factor (GM-CSF) inhalation therapy between 14 patients with PAP. Nevertheless, the increased DLCO was significantly correlated with decreased CEA (r = ‐0.579, P = 0.031) and CYFRA 21-1 (r = ‐0.632, P = 0.015). In 10 PAP patients without GM-CSF inhalation therapy, HDL-C and DLCO significantly decreased while NSE and LDH levels increased after six months of follow-up. The decreased DLCO was significantly correlated with increased LDH (r = ‐0.694, P = 0.026).

Conclusions

Serum CEA, CYFRA21-1, and LDH are valuable serum markers for the evaluation of disease activity of PAP and may predict the response to treatment of PAP.

Whole lung lavage using a rapid infusion system to treat a patient with pulmonary alveolar proteinosis

Whole lung lavage (WLL) is a therapeutic procedure to remove accumulated material by infusing and draining the lungs with lavage fluid. This procedure has been regarded as the current standard of care to treat pulmonary alveolar proteinosis. However, the WLL protocol has not yet been standardized and the technique has been refined and modified a number of times. A rapid infusion system is a device used to infuse blood or other fluids at precise rates and normothermic conditions. This device is not typically used in WLL, which relies on the passive infusion of fluids using the gravitational force. However, in this study we performed WLL using a rapid infusion system, since we aimed to take advantage of its shorter operation time and greater degree of control over fluid volume and temperature. The patient’s symptoms improved without the occurrence of any complications.

What have we learned in interventional pulmonology in the past decade?

Background/aim

The increasing number of lung diseases and particularly pulmonary malignancies has intensified the need for diverse interventions in the field of interventional pulmonology. In recent years we have seen many new developments and expanding applications in the field of interventional pulmonology. This has resulted in an increased number and variety of performed procedures and differing approaches. The purpose of the present study is to provide information on patient characteristics, range of interventions, complication rates, and the evolving approach of an experienced center for interventional pulmonology.

Materials and methods

We retrospectively examined the records of 1307 patients who underwent a total of 2029 interventional procedures in our interventional pulmonology department between January 2008 and December 2017.

Results

About half of the interventional procedures (47.2%) were performed on patients with airway stenosis due to malignant disease. Among patients with benign airway stenosis, the most frequent reason for intervention was postintubation tracheal stenosis. The number of patients who developed complications was 81 (6.2%), and the most common complication was hemorrhage (n = 31, 2.99%); 94.9% (n = 1240) of interventional procedures were performed under general anesthesia, without complications or deaths associated with anesthesia. Only one death (0.076%) occurred in the perioperative period. A total of 18 patients (1.38%) died in the 30-day perioperative and postoperative period. None of the patients with benign airway stenosis died.

Conclusion

Interventional bronchoscopy is an invasive but considerably safe and efficient procedure for selected cases and effective treatment modality for airway obstructions, massive hemoptysis, and foreign body aspiration. Interventional pulmonology is a field of pulmonary medicine that needs effort to progress and provide an opportunity to witness relevant developments, and increase the number of competent physicians and centers.

Shaping the future of an ultra-rare disease: unmet needs in the diagnosis and treatment of pulmonary alveolar proteinosis

PURPOSE OF REVIEW

Pulmonary alveolar proteinosis (PAP) can be considered the archetype of ultra-rare diseases with a prevalence of under 10 cases per million. We discuss the classification of PAP, the current diagnostic practice and the supplementary role of genetic testing and granulocyte-macrophage colony-stimulating factor (GM-CSF) signalling in the diagnosis of congenital and hereditary PAP. We report on novel therapeutic approaches such as GM-CSF substitution, stem cell transplantation, pioglitazone, statins and immunomodulation.

RECENT FINDINGS

The discovery of new genetic mutations underlying this syndrome raises the question whether the classification should be radically revised in the future. Serum GM-CSF autoantibody is the best diagnostic marker for autoimmune PAP, the most common form, but does not correlate with disease severity. Several circulating biomarkers have been investigated to assess disease activity and predict outcome. Imaging techniques have also enormously evolved and offer new tools to quantify disease burden and possibly drive therapeutic decisions. Promising clinical trials are ongoing and will generate new treatment strategies besides or in addition to whole lung lavage in the next future.

SUMMARY

Despite impressive advances in understanding pathogenesis, PAP remains a rare syndrome with several unanswered questions impacting diagnosis, management and treatment, and, as a result, patients' quality of life.

Pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) is a syndrome characterized by the accumulation of alveolar surfactant and dysfunction of alveolar macrophages. PAP results in progressive dyspnoea of insidious onset, hypoxaemic respiratory failure, secondary infections and pulmonary fibrosis. PAP can be classified into different types on the basis of the pathogenetic mechanism: primary PAP is characterized by the disruption of granulocyte-macrophage colony-stimulating factor (GM-CSF) signalling and can be autoimmune (caused by elevated levels of GM-CSF autoantibodies) or hereditary (due to mutations in CSF2RA or CSF2RB, encoding GM-CSF receptor subunits); secondary PAP results from various underlying conditions; and congenital PAP is caused by mutations in genes involved in surfactant production. In most patients, pathogenesis is driven by reduced GM-CSF-dependent cholesterol clearance in alveolar macrophages, which impairs alveolar surfactant clearance. PAP has a prevalence of at least 7 cases per million individuals in large population studies and affects men, women and children of all ages, ethnicities and geographical locations irrespective of socioeconomic status, although it is more-prevalent in smokers. Autoimmune PAP accounts for >90% of all cases. Management aims at improving symptoms and quality of life; whole-lung lavage effectively removes excessive surfactant. Novel pathogenesis-based therapies are in development, targeting GM-CSF signalling, immune modulation and cholesterol homeostasis.

Removal of lung lavage fluid during whole-lung lavage using biphasic cuirass ventilation chest percussion in a patient with autoimmune pulmonary alveolar proteinosis

Autoimmune pulmonary alveolar proteinosis (PAP) is a rare lung disease. Although recombinant human granulocyte macrophage colony-stimulating factor (GM-CSF) therapy has emerged as a new therapeutic modality, whole-lung lavage (WLL) with manual chest percussion has been a standard therapy in advanced cases. The application of biphasic cuirass ventilation (BCV) instead of chest percussion has rarely been reported. We describe the case of a patient with advanced PAP who recovered well in both lungs, without complication, after we performed WLL with BCV under anesthetic mechanical ventilation. Both radiographical chest findings and clinical symptoms were improved, and oxygen therapy was finally withdrawn. This case illustrates that BCV can enhance the effective removal of lavage fluid and is an alternative to manual percussion.

The effectiveness of N-acetylcysteine for an adult case of pulmonary alveolar proteinosis: A case report

Introduction

Pulmonary alveolar proteinosis is a rare disease that is characterized by accumulation of surfactant and phospholipids in the pulmonary alveoli. The current mainstay of treatment is whole lung lavage. There have been rare reports that have revealed the effectiveness of N-acetylcysteine on a secondary PAP.

Case presentation

A 45-year old man complained of shortness of breath and a productive cough with white sputum. He inhaled stone powder as an occupational hazard. CT scan of his chest radiograph showed ground glass changes superimposed on a reticular pattern as the so-called ‘crazy paving’ pattern. Lung biopsy revealed alveolar proteinaceous material with positive PAS stain. He eventually was diagnosed as PAP. He refused a whole lung lavage therapy, so the patient was rendered N-acetylcysteine as an antioxidant, enhanced immunotherapy and anti-infective treatment. His clinical symptoms and radiological manifestation improved gradually. No substantial adverse reactions were reported.

Conclusions

Persistent oral N-acetylcysteine may be an alternative treatment option for secondary PAP.

Whole-lung lavage in a patient with pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) is a rare syndrome in which phospholipoproteinaceous matter accumulates in the alveoli leading to compromised gas exchange. Whole-lung lavage is considered the gold standard for severe autoimmune PAP and offers favorable long-term outcomes. In this case report, we describe the perioperative management and procedural specifics of a patient undergoing WLL for PAP in which an anesthesiologist serves as the proceduralist and a separate anesthesiologist provides anesthesia care for the patient.