[Spontaneous pneumothorax: new concepts and current management]

Spontaneous pneumothorax is a classical medical condition encountered in emergency centers, and by primary care and respiratory physicians. The traditional distinction between primary and secondary pneumothorax, although old and increasingly blurred, still allows to guide initial management and to determine whether pleurodesis is indicated. In case of spontaneous pneumothorax, a targeted family history is essential because it can suggest the presence of a genetic syndrome as the underlying cause of the pneumothorax, a condition often associated with a high risk of pneumothorax recurrence, and the occurrence of extrathoracic manifestations which may be serious if recognized late. This review addresses the classification of spontaneous pneumothorax, its pathogenesis, the risk factors of occurrence including genetic syndromes, and its management.

Probability of sporadic lymphangioleiomyomatosis in women presenting with spontaneous pneumothorax

BACKGROUND

Sporadic lymphangioleiomyomatosis (S-LAM) is a rare low-grade neoplasm of young women characterized by multiple pulmonary cysts leading to progressive dyspnea and recurrent spontaneous pneumothorax (SP). The diagnosis of S-LAM may be delayed by several years. To reduce this delay, chest computed tomography (CT) screening has been proposed to uncover cystic lung disease in women presenting with SP. However, the probability to discover S-LAM in this population has not been determined precisely. The aim of this study was to calculate the probability of finding S-LAM in women presenting with (a) SP, and (b) apparent primary SP (PSP) as first manifestation of S-LAM.

METHODS

Calculations were made by applying the Bayes theorem to published epidemiological data on S-LAM, SP and PSP. Each term of the Bayes equation was determined by meta-analysis, and included: (1) the prevalence of S-LAM in the general female population, (2) the incidence rate of SP and PSP in the general female population, and (3) the incidence rate of SP and apparent PSP in women with S-LAM.

RESULTS

The prevalence of S-LAM in the general female population was 3.03 per million (95% confidence interval 2.48, 3.62). The incidence rate of SP in the general female population was 9.54 (8.15, 11.17) per 100,000 person-years (p-y). The incidence rate of SP in women with S-LAM was 0.13 (0.08, 0.20). By combining these data in the Bayes theorem, the probability of finding S-LAM in women presenting with SP was 0.0036 (0.0025, 0.0051). For PSP, the incidence rate in the general female population was 2.70 (1.95, 3.74) per 100,000 p-y. The incidence rate of apparent PSP in women with S-LAM was 0.041 (0.030, 0.055). With the Bayes theorem, the probability of finding S-LAM in women presenting with apparent PSP as first disease manifestation was 0.0030 (0.0020, 0.0046). The number of CT scans to perform in women to find one case of S-LAM was 279 for SP and 331 for PSP.

CONCLUSION

The probability of discovering S-LAM at chest CT in women presenting with apparent PSP as first disease manifestation was low (0.3%). Recommending chest CT screening in this population should be reconsidered.

[Anti-glomerular basement membrane disease]

Anti-glomerular basement membrane disease is a rare disease. In its classical presentation it associates rapidly progressive glomerulonephritis and diffuse alveolar hemorrhage, linked to the presence of antibodies targeting type IV collagen in the glomerular and alveolar basal membrane. Anti-GBM disease warrants prompt medical management to limit permanent kidney damage and mortality. Treatment includes plasma exchanges to quickly remove pathogenic antibodies and immunosuppressants to stop their production. This article reviews the pathogenesis and current treatments.

Azithromycin alters spatial and temporal dynamics of airway microbiota in idiopathic pulmonary fibrosis

Background

High bacterial burden in lung microbiota predicts progression of idiopathic pulmonary fibrosis (IPF). Azithromycin (AZT) is a macrolide antibiotic known to alter the lung microbiota in several chronic pulmonary diseases and observational studies have shown a positive effect of azithromycin on mortality and hospitalization rate in IPF. However, the effect of AZT on lung microbiota in IPF remains unknown.

Methods

We sought to determine the impact of a three-month course of AZT on lung microbiota in IPF. We assessed sputum and oropharyngeal swab specimens from 24 adults with IPF included in a randomized controlled cross-over trial of a thrice-weekly 500 mg oral AZT. 16S rRNA gene amplicon sequencing and quantitative polymerase chain reaction (qPCR) were performed to assess bacterial communities. Antibiotic resistance genes (ARG) were assessed using real-time qPCR.

Results

AZT significantly decreased community diversity with a stronger and more persistent effect in lower airways (sputum). AZT treatment altered the temporal kinetics of the upper (oropharyngeal swab) and lower airway microbiota, increasing community similarity between the two sites for one month after macrolide cessation.

Patients with an increase in ARG carriage had lower bacterial density and enrichment of the genusStreptococcus. In contrast, patients with more stable ARG carriage had higher bacterial density and enrichment inPrevotella.

Conclusions

AZT caused sustained changes in the diversity and composition of the upper and lower airway microbiota in IPF, with effects on the temporal and spatial dynamics between the two sites.

[Pneumology: what's new in 2022]

This selection of pneumological novelties of the year 2022 is not limited to pharmacological acquisitions but also includes progress in diagnostic strategies and the global management of respiratory diseases. We have chosen three pneumological issues. As cannabis is the most consumed illegal substance in Switzerland, it is important to know its impact on pulmonary physiology. An update of the international guidelines on pulmonary fibrosis as well as the European guidelines on pulmonary hypertension provides practical answers to the many clinical problems encountered in the management of these diseases. The key messages from these two consensus documents are reported here.

[Short telomere syndrome in adults: a rare entity that should be evoked]

Short telomere syndrome (STS) is a group of rare, often underrecognized, diseases caused by defects in telomere-maintenance genes, leading to abnormal telomere shortening and associated with diverse multi-organ manifestations. In pediatric patients, STS typically presents with mucocutaneous or gastrointestinal lesions, bone marrow failure and neoplasia. In adulthood, aplastic bone marrow disease, liver disease and pulmonary fibrosis are classic clinical manifestations. At present, medical treatment options for STS remain limited. Danazol, a synthetic androgenic hormone, can slow down telomere shortening and thus limit the progression of the disease. Finally, hematopoietic, hepatic and pulmonary transplantation, sometimes combined, may be discussed in a multidisciplinary setting in certain situations.

Prevalence of Birt-Hogg-Dubé Syndrome Determined Through Epidemiological Data on Spontaneous Pneumothorax and Bayes Theorem

Background: Birt-Hogg-Dubé syndrome (BHD) is a rare inherited disorder characterized by cutaneous fibrofolliculomas, multiple pulmonary cysts, recurrent spontaneous pneumothorax (SP), and renal tumors. More than 40 years after its description, the prevalence of BHD in the general population remains unknown. This study aimed at determining the prevalence of BHD by applying the Bayes theorem of conditional probability to epidemiological data on SP.

Methods: We performed a meta-analysis of published data on: (1) the probability of having BHD among patients with apparent primary SP (4 studies), (2) the incidence rate of primary SP in the general population (9 studies), and (3) the probability of experiencing a SP in BHD (16 studies). Results were corrected for SP relapses, stratified by gender and year of study publication (before and after 2000), and computed with the Bayes equation.

Results: The probability of having BHD among patients with apparent primary SP was 0.09 (95% confidence interval: 0.07, 0.11) or 9%. It was 0.20 (0.14, 0.27) in women and 0.05 (0.04, 0.07) in men. The incidence rate of primary SP in the general population was 8.69 (6.58, 11.46) per 100,000 person-years (p-y). It was 3.44 (2.36, 4.99) per 100,000 p-y in women and 13.96 (10.72, 18.18) per 100,000 p-y in men, and was about 2 times higher in studies published after 2000 than in those published before 2000. The probability of experiencing at least one SP among patients with BHD was 0.43 (0.31, 0.54) or 43%, without gender difference. By combining these data in the Bayes equation, we found a prevalence of BHD in the general population of 1.86 (1.16, 3.00) per million, with values of 1.86 (1.02, 3.39) per million in men, and 1.88 (0.97, 3.63) per million in women.

Conclusion: The prevalence of BHD in the general population is about 2 cases per million, without difference between genders.

Effect of everolimus on multifocal micronodular pneumocyte hyperplasia in tuberous sclerosis complex

Multifocal micronodular pneumocyte hyperplasia (MMPH) is a benign proliferation of alveolar type II cells presenting as multiple pulmonary nodules at chest imaging, which is frequently seen in patients with tuberous sclerosis complex (TSC). We report a case of a woman with TSC and MMPH who received everolimus, a mechanistic target of rapamycin (mTOR) inhibitor, for the treatment of a subependymal giant cell astrocytoma (SEGA). After 3 months of therapy, a remarkable decrease in density of all pulmonary MMPH lesions was observed, without any change in size. This shows that everolimus is active on MMPH similarly to its effects on SEGA, renal angiomyolipomas, and pulmonary lymphangioleiomyomatosis in TSC, and suggests that the dysregulated activation of mTOR which characterizes TSC also plays a role in the pathogenesis of MMPH.

[New developments in systemic sclerosis-associated interstitial lung disease]

Interstitial lung disease is a frequent complication of systemic sclerosis and has now become the leading cause of death in this disorder. It mainly occurs during the first five years after the diagnosis of systemic sclerosis. Various risk factors are associated with the occurrence of interstitial lung disease, including the presence of anti-topoisomerase I antibodies (Scl-70) and the diffuse cutaneous form of systemic sclerosis. The most common radio-pathological presentation is nonspecific interstitial pneumonia, followed by usual interstitial pneumonia. The classical immunosuppressive treatment of systemic sclerosis-associated interstitial lung disease is evolving, as recent studies suggest a beneficial effect of biological agents such as rituximab and tocilizumab, and antifibrotic drugs such as nintedanib.

Pitfalls in diagnosis of infiltrative lung disease by CT

The diagnosis of interstitial lung disease may be challenging, especially in atypical disease. Various factors must be considered when performing and reading a chest CT examination for interstitial lung disease, because each of them may represent a source of misinterpretation. Firstly, technical aspects must be mastered, including acquisition and reconstruction parameters as well as post-processing. Secondly, mistakes in interpretation related to the inaccurate description of predominant features, potentially leading to false-positive findings, as well as satisfaction of search must be avoided. In all cases, clinical context, coexisting chest abnormalities and previous examinations must be integrated into the analysis to suggest the most appropriate differential diagnosis.

Birt-Hogg-Dubé syndrome

Birt–Hogg–Dubé syndrome (BHD) is a rare inherited autosomal dominant disorder caused by germline mutations in the tumour suppressor gene FLCN, encoding the protein folliculin. Its clinical expression typically includes multiple pulmonary cysts, recurrent spontaneous pneumothoraces, cutaneous fibrofolliculomas and renal tumours of various histological types. BHD has no sex predilection and tends to manifest in the third or fourth decade of life. Multiple bilateral pulmonary cysts are found on chest computed tomography in >80% of patients and more than half experience one or more episodes of pneumothorax. A family history of pneumothorax is an important clue, which suggests the diagnosis of BHD. Unlike other cystic lung diseases such as lymphangioleiomyomatosis and pulmonary Langerhans cell histiocytosis, BHD does not lead to progressive loss of lung function and chronic respiratory insufficiency. Renal tumours affect about 30% of patients during their lifetime, and can be multiple and recurrent. The diagnosis of BHD is based on a combination of genetic, clinical and/or skin histopathological criteria. Management mainly consists of early pleurodesis in the case of pneumothorax, periodic renal imaging for tumour detection, and diagnostic work-up in search of BHD in relatives of the index patient.

Birt–Hogg–Dubé syndrome is a rare genetic disorder characterised by multiple lung cysts, recurrent pneumothoraces, skin lesions and kidney tumours. As the presenting symptoms may be respiratory, chest physicians should be able to identify this disease.https://bit.ly/2xsOTuk

Lung function in Birt-Hogg-Dubé syndrome: a retrospective analysis of 96 patients

Background

Birt-Hogg-Dubé syndrome (BHD) is a rare autosomal dominant disorder caused by mutations in the FLCN gene coding for folliculin. Its clinical expression includes cutaneous fibrofolliculomas, renal tumors, multiple pulmonary cysts, and recurrent spontaneous pneumothoraces. Data on lung function in BHD are scarce and it is not known whether lung function declines over time. We retrospectively assessed lung function at baseline and during follow-up in 96 patients with BHD.

Results

Ninety-five percent of BHD patients had multiple pulmonary cysts on computed tomography and 59% had experienced at least one pneumothorax. Mean values of forced expiratory volume in 1 second (FEV₁), forced vital capacity (FVC), FEV₁/FVC ratio, and total lung capacity were normal at baseline. Mean (standard deviation) residual volume (RV) was moderately increased to 116 (36) %pred at baseline, and RV was elevated > 120%pred in 41% of cases. Mean (standard deviation) carbon monoxide transfer factor (DLco) was moderately decreased to 85 (18) %pred at baseline, and DLco was decreased < 80%pred in 33% of cases. When adjusted for age, gender, smoking and history of pleurodesis, lung function parameters did not significantly decline over a follow-up period of 6 years.

Conclusions

Cystic lung disease in BHD does not affect respiratory function at baseline except for slightly increased RV and reduced DLco. No significant deterioration of lung function occurs in BHD over a follow-up period of 6 years.

[Asthma and COPD management during the COVID-19 pandemic]

Numerous patients with asthma or COPD are likely to be infected with SARS-CoV-2 virus. Although data is limited, patients with severe and/or uncontrolled asthma and those with COPD appear to be at increased risk of a more severe course of COVID-19 infection. Usual recommendations for management of asthma and COPD remain valid despite the ongoing epidemic. However, lung function testing and nebulisers should be performed with caution during the COVID-19 pandemic due to a potential risk of virus aerosolisation and contagion during the procedure. Particular care must be taken to identify and protect patients who are particularly vulnerable to COVID-19 infection. Asthma and COPD treatments should be pursued and adapted to ensure optimal control of the lung disease throughout the epidemic, thus reducing the risk of severe COVID-19 disease.

Relationship between pneumonitis induced by immune checkpoint inhibitors and the underlying parenchymal status: a retrospective study

In patients with primary or secondary lung tumour treated with immune checkpoint inhibitors, immune-related pneumonitis is a rare adverse event but may evolve to respiratory failure. Prompt management is required and usually consists of treatment interruption and immunosuppressive drug administration. The aim of this study was to evaluate relationships between immune-related pneumonitis and pre-existing parenchymal status, especially tumour location and history of chest radiotherapy.

Computed tomography (CT) scans of patients with immune-related pneumonitis were retrospectively reviewed. Pattern, distribution and extent of pneumonitis were assessed in six lung regions. In patients who received radiotherapy, the extent of pneumonitis was evaluated according to the radiation field.

Among 253 patients treated with immunotherapy, 15 cases of immune-related pneumonitis were identified. 10 had previous or concomitant chest radiotherapy in addition to immunotherapy. At CT scan, 29 (33%) out of 88 regions encompassed the primary tumour (n=4), a lung metastasis (n=4) and/or radiation fields (n=21). A significantly higher prevalence of parenchymal involvement by immune-related pneumonitis occurred within areas of primary or metastatic malignancy and/or radiation field (97%) as compared to other areas (3%, p=0.009). Lung regions affected by the primary tumour, metastasis or radiotherapy had a higher probability of immune-related pneumonitis than others (OR 10.8, p=0.024). An organising pneumonia (OP) pattern was more frequent after radiotherapy (70% versus 0%, p=0.024), whereas nonspecific interstitial pneumonia features were more commonly seen in radiotherapy-naive patients (100% versus 10%, p=0.002).

In patients with primary or secondary lung tumour treated with immune checkpoint inhibitors, immune-related pneumonitis is preferentially located within lung areas involved by tumour and/or radiation fields.

In patients with primary or secondary lung tumour treated by immune checkpoint inhibitors, immune-related pneumonitis induced by these agents is preferentially located within lung areas involved by tumour and/or radiation fieldshttp://bit.ly/2NJZmGx

Immunotherapy-Induced Airway Disease: A New Pattern of Lung Toxicity of Immune Checkpoint Inhibitors

Immune checkpoint inhibitors (ICIs) have been shown to improve overall and progression-free survival in various cancers but have been associated with various immune-related adverse events (IRAEs), including interstitial lung disease, especially organizing pneumonia. We report 2 cases of isolated severe airway disease attributable to ICIs, a rarely reported pattern of lung toxicity. The first patient received nivolumab with or without ipilimumab in a randomized double-blind trial for locoregional metastatic melanoma. The second patient was treated with nivolumab for lung adenocarcinoma. An IRAE was suspected in both cases due to a temporal relationship between ICI initiation and symptom onset. ICIs were stopped, and high-dose prednisone, inhaled corticosteroids, and bronchodilators were administered, allowing a rapid clinical and functional improvement in Patient 1. In Patient 2, despite prolonged high-dose prednisone, only a stabilization of forced expiratory volume in 1 s could be achieved, and the disease course was complicated by respiratory infections resulting in further loss of lung function. The patient died 1 year later due to progression of metastatic disease. These 2 cases suggest that pulmonary IRAEs secondary to ICIs may present as isolated bronchitis or bronchiolitis, with variable outcomes following ICI withdrawal and systemic corticosteroids.

[Rheumatoid arthritis-associated interstitial lung disease : new genetic data and therapeutic perspectives]

Diffuse interstitial lung disease (ILD) is one of the most frequent extra-articular manifestation of rheumatoid arthritis (RA) and is an important factor of morbidity and mortality. However, the physiopathological mechanisms underlying RA-associated ILD remain poorly understood, and disease management is difficult in the absence of effective treatments and international guidelines. The recent identification of genetic variants and mutations similar to those observed in idiopathic pulmonary fibrosis (IPF), a disease affecting exclusively the lung, provides new insights into the understanding of RA-associated ILD. Furthermore, new antifibrotic drugs approved for the treatment of IPF, including pirfenidone and nintedanib, could also prove to be effective for RA-associated ILD. Studies are ongoing to confirm this hypothesis.

Air travel and incidence of pneumothorax in lymphangioleiomyomatosis

BACKGROUND

Pulmonary lymphangioleiomyomatosis (LAM) is a rare disease of women characterized by multiple lung cysts leading to respiratory insufficiency and frequent pneumothorax (PT). Air travel (AT) could increase the risk of PT in LAM through rupture of subpleural cysts induced by atmospheric pressure changes in aircraft cabin. To determine whether AT increases the risk of PT in LAM, we performed a retrospective survey of members of European LAM patient associations. A flight-related PT was defined as occurring ≤30 days after AT.

RESULTS

145 women reported 207 PT. In 128 patients with available data, the annual incidence of PT was 8% since the first symptoms of LAM and 5% since LAM diagnosis, compared to 0.006% in the general female population. Following surgical or chemical pleurodesis, the probability of remaining free of PT recurrence was respectively 82, 68, and 59% after 1, 5 and 10 years, as compared to only 55, 46 and 39% without pleurodesis (p = 0.026). 70 patients with available data performed 178 AT. 6 flight-related PT occurred in 5 patients. PT incidence since first symptoms of LAM was significantly higher ≤30 days after AT as compared to non-flight periods (22 versus 6%, risk ratio 3.58, confidence interval 1.40-7.45).

CONCLUSIONS

The incidence of PT in LAM is about 1000 times higher than in the general female population, and is further increased threefold after AT. Chemical or surgical pleurodesis partly reduces the risk of PT recurrence in LAM.

Evaluating disease severity in idiopathic pulmonary fibrosis

Accurate assessment of idiopathic pulmonary fibrosis (IPF) disease severity is integral to the care provided to patients with IPF. However, to date, there are no generally accepted or validated staging systems. There is an abundance of data on using information acquired from physiological, radiological and pathological parameters, in isolation or in combination, to assess disease severity in IPF. Recently, there has been interest in using serum biomarkers and computed tomography-derived quantitative lung fibrosis measures to stage disease severity in IPF. This review will focus on the suggested methods for staging IPF, at baseline and on serial assessment, their strengths and limitations, as well as future developments.

Host-Microbial Interactions in Idiopathic Pulmonary Fibrosis

RATIONALE

Changes in the respiratory microbiome are associated with disease progression in idiopathic pulmonary fibrosis (IPF). The role of the host response to the respiratory microbiome remains unknown.

OBJECTIVES

To explore the host-microbial interactions in IPF.

METHODS

Sixty patients diagnosed with IPF were prospectively enrolled together with 20 matched control subjects. Subjects underwent bronchoalveolar lavage (BAL), and peripheral whole blood was collected into PAXgene tubes for all subjects at baseline. For subjects with IPF, additional samples were taken at 1, 3, and 6 months and (if alive) 1 year. Gene expression profiles were generated using Affymetrix Human Gene 1.1 ST arrays.

MEASUREMENTS AND MAIN RESULTS

By network analysis of gene expression data, we identified two gene modules that strongly associated with a diagnosis of IPF, BAL bacterial burden (determined by 16S quantitative polymerase chain reaction), and specific microbial operational taxonomic units, as well as with lavage and peripheral blood neutrophilia. Genes within these modules that are involved in the host defense response include NLRC4, PGLYRP1, MMP9, and DEFA4. The modules also contain two genes encoding specific antimicrobial peptides (SLPI and CAMP). Many of these particular transcripts were associated with survival and showed longitudinal overexpression in subjects experiencing disease progression, further strengthening the relationship of the transcripts with disease.

CONCLUSIONS

Integrated analysis of the host transcriptome and microbial signatures demonstrated an apparent host response to the presence of an altered or more abundant microbiome. These responses remained elevated in longitudinal follow-up, suggesting that the bacterial communities of the lower airways may act as persistent stimuli for repetitive alveolar injury in IPF.

Recent advances in understanding idiopathic pulmonary fibrosis

Despite major research efforts leading to the recent approval of pirfenidone and nintedanib, the dismal prognosis of idiopathic pulmonary fibrosis (IPF) remains unchanged. The elaboration of international diagnostic criteria and disease stratification models based on clinical, physiological, radiological, and histopathological features has improved the accuracy of IPF diagnosis and prediction of mortality risk. Nevertheless, given the marked heterogeneity in clinical phenotype and the considerable overlap of IPF with other fibrotic interstitial lung diseases (ILDs), about 10% of cases of pulmonary fibrosis remain unclassifiable. Moreover, currently available tools fail to detect early IPF, predict the highly variable course of the disease, and assess response to antifibrotic drugs.

Recent advances in understanding the multiple interrelated pathogenic pathways underlying IPF have identified various molecular phenotypes resulting from complex interactions among genetic, epigenetic, transcriptional, post-transcriptional, metabolic, and environmental factors. These different disease endotypes appear to confer variable susceptibility to the condition, differing risks of rapid progression, and, possibly, altered responses to therapy. The development and validation of diagnostic and prognostic biomarkers are necessary to enable a more precise and earlier diagnosis of IPF and to improve prediction of future disease behaviour. The availability of approved antifibrotic therapies together with potential new drugs currently under evaluation also highlights the need for biomarkers able to predict and assess treatment responsiveness, thereby allowing individualised treatment based on risk of progression and drug response. This approach of disease stratification and personalised medicine is already used in the routine management of many cancers and provides a potential road map for guiding clinical care in IPF.

Acute eosinophilic and neutrophilic pneumonia following transarterial chemoembolization with drug-eluting beads loaded with doxorubicin for hepatocellular carcinoma: a case report

At an intermediate or advanced stage, i.e. stage B or C, based on the Barcelona Clinic Liver Cancer classification of hepatocellular carcinoma (HCC), transarterial chemoembolization (TACE) may be offered as a treatment of palliative intent. We report the case of a patient suffering from acute respiratory distress syndrome after TACE with drug-eluting beads loaded with doxorubicin for HCC. To our knowledge, this is the first case described where a bronchoalveolar lavage was performed, and where significant levels of alveolar eosinophilia and neutrophilia were evident, attributed to a pulmonary toxicity of doxorubicin following liver chemoembolization.

[Lung and pregnancy]

During pregnancy several adaptations develop in response to the enhanced maternal and fetal metabolic needs. This review summarizes the major cardiorespiratory modifications of pregnancy as well as their consequences in chronic respiratory diseases such as restrictive ventilatory defects (post-tuberculosis pneumonectomy, kyphoscoliosis, neuromuscular disorders), asthma, cystic fibrosis, and pulmonary hypertension. It is important to recognize early the cardiorespiratory situations for which pregnancy is contraindicated or associated with a high risk of respiratory complications. Clinical management by an expert and often pluridisciplinary team is recommended.