Primary spontaneous pneumothorax: a diffuse disease of the pleura

Radiographic chest wall abnormalities in primary spontaneous pneumothorax identified by artificial intelligence

Primary spontaneous pneumothorax (PSP) primarily affects slim and tall young males. Exploring the etiological link between chest wall structural characteristics and PSP is crucial for advancing treatment methods. In this case-control study, chest computed tomography (CT) images from patients undergoing thoracic surgery, with or without PSP, were analyzed using Artificial Intelligence. Convolutional Neural Network (CNN) model of EfficientNetB3 and InceptionV3 were used with transfer learning on the Imagenet to compare the images of both groups. A heatmap was created on the chest CT scans to enhance interoperability, and the scale-invariant feature transform (SIFT) was adopted to further compare the image level. A total of 2,312 CT images of 26 non-PSP patients and 1,122 CT images of 26 PSP patients were selected. Chest-wall apex pit (CAP) was found in 25 PSP and three non-PSP patients (p < 0.001). The CNN achieved a testing accuracy of 93.47 % in distinguishing PSP from non-PSP based on chest wall features by identifying the existence of CAP. Heatmap analysis demonstrated CNN's precision in targeting the upper chest wall, accurately identifying CAP without undue influence from similar structures, or inappropriately expanding or minimizing the test area. SIFT results indicated a 10.55 % higher mean similarity within the groups compared to between PSP and non-PSP (p < 0.001). In conclusion, distinctive radiographic chest wall configurations were observed in PSP patients, with CAP potentially serving as an etiological factor linked to PSP. This study accentuates the potential of AI-assisted analysis in refining diagnostic approaches and treatment strategies for PSP.

Development of pneumatocele and spontaneous pneumothorax as a late complication of COVID-19 pneumonia

SARS-COV2 pandemic has spread like wildfire and has affected all the countries worldwide. The virus mainly affects the lungs and has numerous manifestations. The development of spontaneous pneumatocele and pneumothorax has rarely been reported in the literature, especially in spontaneously breathing patients. We report two cases of COVID-19 patients who developed these complications after discharge from our hospital. These complications are uncommon but can be potentially fatal and the treating physician should keep these complications as differential while managing such cases.

Fleischner Society: Glossary of Terms for Thoracic Imaging

Members of the Fleischner Society have compiled a glossary of terms for thoracic imaging that replaces previous glossaries published in 1984, 1996, and 2008, respectively. The impetus to update the previous version arose from multiple considerations. These include an awareness that new terms and concepts have emerged, others have become obsolete, and the usage of some terms has either changed or become inconsistent to a degree that warranted a new definition. This latest glossary is focused on terms of clinical importance and on those whose meaning may be perceived as vague or ambiguous. As with previous versions, the aim of the present glossary is to establish standardization of terminology for thoracic radiology and, thereby, to facilitate communications between radiologists and clinicians. Moreover, the present glossary aims to contribute to a more stringent use of terminology, increasingly required for structured reporting and accurate searches in large databases. Compared with the previous version, the number of images (chest radiography and CT) in the current version has substantially increased. The authors hope that this will enhance its educational and practical value. All definitions and images are hyperlinked throughout the text. Click on each figure callout to view corresponding image. © RSNA, 2024 Supplemental material is available for this article. See also the editorials by Bhalla and Powell in this issue.

The contemporary management of spontaneous pneumothorax in adults

Spontaneous pneumothorax is a common presentation, and there has been a recent surge of research into the condition. With the recent publication of the new British Thoracic Society guidelines and the upcoming European Respiratory Society guidelines, we provide a concise up-to-date summary of clinical learning points. In particular we focus on the role of conservative or ambulatory management, as well as treatment options for persistent air leak and guidance for when to refer to thoracic surgeons for the prevention of the recurrence of pneumothorax.

Educational aims

To give up-to-date guidance on the acute management of spontaneous pneumothorax, including the role of conservative or ambulatory managementTo discuss the different treatment options for persistent air leak.To guide physicians on when to refer patients to thoracic surgeons for the prevention of the recurrence of pneumothorax.

The miRNA-24, miRNA-21 expressions and matrix metalloproteinase-7 level in exhaled breath condensate of children with primary spontaneous pneumothorax

Bullous lung diseases may cause primary spontaneous pneumothorax (PSP) in children. The microRNAs (miRNAs) are non-coding RNAs that participate in regulation of inflammation and cancer. We hypothesized that children with bullous lung disease and PSP may have altered miRNA expressions in their exhaled breath condensates (EBCs). Therefore, a prospective study was performed to evaluate the miRNA-24 and 21 expression, and the matrix metalloproteinase-7 (MMP-7) levels in EBC of children with PSP. Children with PSP were evaluated for age, gender, clinical features and results of surgical treatment. EBC samples (500-1000 ml) were collected to evaluate the miRNA-21, 24 expressions, and MMP-7, and tissue-inhibitor-MMP-1 (TIMP-1) levels. miRNA expressions and MMP levels of patients were compared with healthy controls (control group (CG),n= 12). Subjects (n= 16) with a mean age of 15 years (10-19 years), and a male-to-female ratio of 14:2 were enrolled in this study. The most common presenting symptom was sudden chest pain (n= 14). In 62.5% of the cases an underlying bullous lung disease were detected. During an average of 16.6 months (1-60 months) follow up period, four subjects relapsed. The mean MMP-7 (1.74-1.57 ng ml^-1), and TIMP-1 (1.92-1.84 ng ml^-1) levels were similar between both groups (p> 0.05). miRNA-24 expression was significantly decreased in the PSP group, when compared to the CG (0.16-1 2^-ΔΔCT,p< 0.05). In addition, the miRNA-21 expression was not different between the two groups (p> 0.05). In conclusion, the miRNA-24 levels were significantly decreased in children with PSP. Taken together, children with PSP, especially those with bullous disease, should be closely monitored in the long-term period.

Chest CT scan for the screening of air anomalies at risk of pulmonary barotrauma for the initial medical assessment of fitness to dive in a military population

Introduction: The presence of intra-pulmonary air lesions such as cysts, blebs and emphysema bullae, predisposes to pulmonary barotrauma during pressure variations, especially during underwater diving activities. These rare accidents can have dramatic consequences. Chest radiography has long been the baseline examination for the detection of respiratory pathologies in occupational medicine. It has been replaced since 2018 by the thoracic CT scan for military diving fitness in France. The objective of this work was to evaluate the prevalence of the pulmonary abnormalities of the thoracic CT scan, and to relate them to the characteristics of this population and the results of the spirometry.

Methods: 330 records of military diving candidates who underwent an initial assessment between October 2018 and March 2021 were analyzed, in a single-center retrospective analysis. The following data were collected: sex, age, BMI, history of respiratory pathologies and smoking, treatments, allergies, diving practice, results of spirometry, reports of thoracic CT scans, as well as fitness decision.

Results: The study included 307 candidates, mostly male, with a median age of 25 years. 19% of the subjects had abnormal spirometry. We identified 25% of divers with CT scan abnormalities. 76% of the abnormal scans were benign nodules, 26% of which measured 6 mm or more. Abnormalities with an aerial component accounted for 13% of the abnormal scans with six emphysema bullae, three bronchial dilatations and one cystic lesion. No association was found between the presence of nodules and the general characteristics of the population, whereas in six subjects emphysema bullae were found statistically associated with active smoking or abnormal spirometry results.

Conclusion: The systematic performance of thoracic CT scan in a young population free of pulmonary pathology revealed a majority of benign nodules. Abnormalities with an aerial component are much less frequent, but their presence generally leads to a decision of unfitness. These results argue in favor of a systematic screening of aeric pleuro-pulmonary lesions during the initial assessment for professional divers.

The Collateral Damage of the Pandemic on Non-COVID Related Pneumothorax Patients: A Retrospective Cohort Study

Background: Since the onset of the COVID-19 pandemic, there have been many reported cases showing the consequences—or the collateral damages—of COVID-19 on patients with non-COVID-related diseases. This study aimed to compare the clinical manifestations and treatment results of non-COVID-related pneumothorax patients before and during the pandemic. Methods: We retrospectively reviewed non-COVID-related pneumothorax patients who visited our hospital before the onset of the pandemic and during the pandemic. The primary outcome was the difference in the amount of pneumothorax between the two periods, and the secondary outcome was the difference in the treatment results between them. Multivariable logistic regression was conducted to find risk factors related to massive pneumothorax. Results: There were 122 and 88 patients in the pre-pandemic and pandemic groups, respectively. There was no significant difference between the two groups with respect to the preoperative demographic variables. However, the median amount of pneumothorax was significantly higher in the pandemic group (pre-pandemic: 34.75% [interquartile range (IQR) 18.30–62.95] vs. pandemic: 53.55% [IQR 33.58–88.80], p < 0.0001) and massive pneumothorax were more frequent in the pandemic group (52.3% vs. 30.3%, p = 0.002). Furthermore, more patients experienced re-expansion pulmonary edema after treatments during the pandemic (p = 0.0366). In multivariable analysis, the pandemic (OR: 2.70 [95% CI 1.49–4.90], p = 0.0011) was related to the occurrence of massive pneumothorax. Conclusion: During the pandemic, patients presented with a larger size of pneumothorax and had more re-expansion pulmonary edema, even in a country that handled the COVID-19 pandemic relatively well.

Management of primary spontaneous pneumothorax: Our single-center, five-year experience

BACKGROUND

In this study, we aimed to analyze the effects of admission time to the hospital and different variables on the treatment efficiency and to evaluate the recurrence during the clinical management process in patients with the diagnosis of primary spontaneous pneumothorax.

METHODS

A total of 149 patients with primary spontaneous pneumothorax (131 males, 18 females; mean age: 24.8±6.8 years; range, 17 to 35 years) treated in our clinic between January 2015 and December 2019 were retrospectively analyzed. Time from symptom onset to hospital admission (admission time) was classified as three periods: <24 h, between 24 and 72 h, and >72 h. Data including admission time, demographic and clinical characteristics, smoking history, body mass index, the use of pleurectomy or pleural abrasion during surgery were collected from the charts of the patients.

RESULTS

Admission time had no statistically significant effect on the length of hospital stay, recurrence, and the need for surgery. Male sex, smoking history, and lower body mass index had no significant effect on the recurrence. Recurrence and length of hospital stay did not significantly differ between the patients in whom pleurectomy or pleural abrasion added to the procedure during the operation.

CONCLUSION

A longer interval between symptom onset and hospital admission and lower body mass index have no adverse effect on treatment outcomes and the recurrence in patients with primary spontaneous pneumothorax. Despite the fact that surgical treatment significantly decreases the recurrence rate, pleurectomy and pleural abrasion techniques have no significant difference on the clinical influence and recurrence of these patients.

Effects of Different Treatment Regimens on Primary Spontaneous Pneumothorax: A Systematic Review and Network Meta-Analysis

PURPOSE

The best treatment strategy for primary spontaneous pneumothorax is controversial and varies widely in practice.

METHODS

Literatures were searched from databases till 24 August 2021. A Bayesian network meta-analysis was conducted to compare the outcomes of various treatments with the following endpoints: recurrence rate, postoperative chest tube duration, postoperative air leakage duration, length of hospital stay, and complications rate.

RESULTS

In all, 7210 patients of 20 randomized controlled trials and 17 cohort studies were included. Surgery had a significantly lower recurrence rate compared to other treatments. Besides, bullectomy (BT) combined with chemical pleurodesis (CP), mechanical pleurodesis, or staple line coverage (SLC) can reduce the recurrence rate compared to BT alone, but none of them were statistically significant. In terms of reducing chest tube duration, BT with tubular Neoveil outperformed BT + pleural abrasion (mean difference [MD], 95% confidence interval [CI]: -2.5 [-4.63, -0.35]) and BT + apical pleurectomy (MD, 95% CI: -2.72 [-5.16, -0.27]).

CONCLUSIONS

Surgical methods were superior to manual aspiration (MA), chest tube drainage (CTD), and conservative treatment in terms of recurrence reduction. There was no significant difference between MA and CTD in reducing the recurrence rate. Among surgical methods, CP is more effective than mechanical pleurodesis and SLC among the additional procedures based on BT.

A Rare Case of Interlobar Pneumothorax

BACKGROUND: Pneumothorax is a severe medical condition characterized by the collection of air in one or several spaces of the pleura. A rare subtype of pneumothorax where air is restricted in interlobar pleural space, mostly due to the previous fibrous pleural adhesions, is known as interlobar pneumothorax. CASE PRESENTATION: We present a rare case of a 58-year-old female admitted to the emergency department due to difficulty on breathing, hemoptysis, and discomfort in the right anterior axillary line, which worsened with inspiration and was associated with breathlessness during physical activity. The diagnosis was confirmed by thoracic multi slice computed tomography (MSCT), showing that air was located between the middle and lower lobes of the right lung , measuring 7 × 5 × 2.5 cm (transversal × oblique cranio-caudal × antero-posterior), representing interlobar pneumothorax. DISCUSSION: Cases of interlobar pneumothorax need to be carefully differentiated and evaluated, while skin folds, overlapping breast margin, interlobar fissure, bullae in the apices, pneumomediastinum, pneumopericardium, inferior pulmonary ligament air collection, pneumatocele, and air collection in the intrathoracic extrapleural space, can mimic pneumothorax and make diagnosing very challenging.

Electrocardiographic changes in young patients with spontaneous pneumothorax: A retrospective study

Primary spontaneous pneumothorax (PSP) commonly occurs in adolescents. PSP symptoms can mimic cardiac event. We aimed to examine electrocardiography (ECG) changes that accompanied PSP in relation to side and size of pneumothorax.A retrospectively reviewed 57 adolescents presented with PSP and underwent a cardiac evaluation.Overall, 49 patients (86%) were male, median age of 16 years. Of these, 1 patient had a known mitral valve prolapse. In 56 patients the initial episode of PSP was unilateral (16 left sided and 40 right sided), and 1 was bilateral. The main initial symptom was chest pain or dyspnea and chest pain 66.6% and 33.3% respectively. Small pneumothorax was right and left sided in 1and 8 patients respectively, medium right (n = 8) medium left (n = 22), large right (n = 7) and large left (n = 10). One additional patient had medium bilateral pneumothorax. ECG findings were abnormal in 12 patients (21%) and included ST elevation in 5 patients, inverted T wave in 2 patients, incomplete right bundle branch block in 2 patients, poor R wave progression, left axis deviation and low QRS voltage in 1 patient each. Only 2 patients had abnormal echocardiography findings, MPV (n = 1) and minimal mitral and tricuspid regurgitation (n = 1). Serum troponin-T levels were normal in all patients.ECG changes were found in 21% among pediatric patients with PSP. No correlation was observed between ECG changes and side/size of pneumothorax. It is important to rule out pneumothorax among children presented with chest pain, dyspnea and ECG changes.

Sudden unexpected death due to spontaneous pneumothorax caused by ruptured bilateral pulmonary bullae

Sudden unexpected death due to pneumothoraces caused by spontaneous rupture of bilateral pulmonary bullae is rare. This article reports the case of a 16-year-old girl who experienced this rare phenomenon without any precipitating factors. The patient did not have a history of chest pains or smoking but experienced chest tightness in the early morning and collapsed and died 4 h later. Autopsy identified the cause of death to be bilateral pneumothoraces and massive bilateral pulmonary collapse (atelectasis) due to ruptured apical bullae of the bilateral lungs. No injuries or other significant pathological findings were identified. A low body mass index (16.5) may have been a risk factor for the spontaneous tension pneumothoraces. In some situations, genetic counseling and testing may be helpful in identifying a heritable process associated with spontaneous pneumothoraces.

Primary spontaneous pneumothorax in children: A single institutional experience

BACKGROUND

The treatment of primary spontaneous pneumothorax (PSP) remains controversial. We aimed to examine the role of chest computed tomography (CT), the advantages of pigtail catheter versus chest tube regarding duration of drainage or hospitalization period, and the impact of small PSP and surgical treatment on recurrence rate.

METHODS

We retrospectively reviewed the medical records of 109 children with PSP (20 years' period). Patients with recurrent and those with non-recurrent PSP were compared.

RESULTS

We recorded 183 episodes of PSP (45% recurrences), 89 patients (97%) were male, and the median age at presentation was 16 years. There were no significant differences between recurrence and non-recurrence PSP regarding age, gender, medical background, presentation symptoms, type of chest drain, median hospitalization length and median follow-up period. Recurrences were less frequent among patients who presented with small PSP and were treated conservatively (P = 0.029). PSP was almost always unilateral and the recurrence was observed ipsilateral in almost 80% of the cases. CT was more frequently used and blebs/bullae were more frequently found among patients with recurrent PSP. Pigtail use had no advantage in reducing hospitalization period and surgical procedures prevented recurrences.

CONCLUSION

The size of pneumothorax at presentation helps to predict recurrences. There are no differences regarding duration of drainage or hospitalization period in the use of pigtail compared to chest tube. CT helps evaluate findings in the lungs in recurrent cases of PSP and surgery prevents recurrences effectively.

Histopathologic Findings Associated With Matrix Metalloproteinases Proceeding to Recurrence of Primary Spontaneous Pneumothorax in Adolescents

Background: Primary spontaneous pneumothorax is potentially life-threatening, and its recurrence is always a serious problem. Pathological examination provides molecular insights into the pathophysiology of primary spontaneous pneumothorax. Objectives: To investigate the association of histopathologic features of primary spontaneous pneumothorax with matrix metalloproteinase expression and their relevance to the recurrence. Methods: A total of 217 tissue section slides in 172 adolescent patients with primary spontaneous pneumothorax were retrospectively reviewed from January 2001 to June 2020. All histopathologic features were recorded and pathologic findings related to ipsilateral recurrence and second surgery were analyzed. Serum levels of matrix metalloproteinases were prospectively measured in 25 primary spontaneous pneumothorax patients receiving surgery and 18 healthy controls. Their relevance to the histopathologic features of primary spontaneous pneumothorax related to its recurrence was also examined. Results: The major presenting histopathologic findings of primary spontaneous pneumothorax were bleb/bulla (98%) followed by fibrosis (68%). Low prevalence of the pathologic findings of granulation tissue and macrophage accumulation were significantly associated with recurrent primary spontaneous pneumothorax, whereas fibrosis was significantly higher in patients receiving more than once surgery. Furthermore, the ratios of matrix metalloproteinase-2/tissue inhibitor of metalloproteinase-1 and matrix metalloproteinase-9/tissue inhibitor of metalloproteinase-1 were significantly higher in theses pathological findings as well as multinucleated giant cells and mesothelial cell hyperplasia in comparison with healthy controls. Conclusions: Low prevalence of macrophage accumulation and granulation tissue related to the overexpression of matrix metalloproteinase-2 and-9 activities may contribute to healing impairment and primary spontaneous pneumothorax recurrence.

Pneumothorax In Covid-19 Pneumonia: A case series

BACKGROUND

Coronavirus disease 2019 (Covid-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It mainly affects the lungs and common symptoms are fever, cough and shortness of breath. Pneumothorax has been noted to complicate Covid-19 cases requiring hospital admission, however the exact incidence and risk factors are still unknown.

DISCUSSION

We present a series of 3 cases of primary spontaneous pneumothorax with Covid-19 pneumonia. All cases in our series did not require positive pressure ventilation and none had any pre-existing lung disease. All were never smokers and had favourable outcomes despite having severe Covid-19 with a pneumothorax during the course of the disease. In our literature review we discuss several plausible mechanisms and risk factors resulting in a pneumothorax with Covid-19.

CONCLUSION

Our cases are a reminder that an acute deterioration with hypoxia in a Covid-19 patient could indicate a pneumothorax. Pneumothorax is one of the reported complications in Covid-19 and clinician vigilance is required during assessment of patients, as both share the common symptom of breathlessness and therefore can mimic each other.

Detection and Management of Intraoperative Pneumothorax during Laparoscopic Cholecystectomy

Intraoperative pneumothorax is a rare but potentially lethal complication during general anesthesia. History of lung disease, barotrauma, and laparoscopic surgery increase the risk of developing intraoperative pneumothorax. The diagnosis during surgery could be difficult because the signs are often nonspecific. We report a case of a middle-aged gentleman who developed right pneumothorax during an elective laparoscopic cholecystectomy. The patient had no risk factors for adverse events during the preoperative assessment (ASA1). The patient underwent general anesthesia and was put on mechanical ventilation. The first signs of abnormality immediately after surgical port insertion were tachycardia and low oxygen saturation in addition to sings of airway obstruction. The diagnosis of pneumothorax was made clinically by chest auscultation and later confirmed by intraoperative chest radiograph. Supportive treatment was started immediately through halting the surgery and manually ventilating the patient using 100% oxygen. Definitive treatment was then done by inserting an intercostal tube. After stabilizing the patient, the surgery was completed; then, the patient was extubated and shifted to the surgical ward. Postoperative computed tomography (CT) scan was done and showed only minimal liver laceration. The patient was discharged after removing the intercostal tube and was stable at the follow-up visit. Therefore, it is important to have a high index of suspicion to early detect and treat such complication. In addition, good communication with the surgeon and use of available diagnostic tools will aid in the proper management of such cases.

A project to assess the quality of the published guidelines for managing primary spontaneous pneumothorax from the Italian Society of Thoracic Surgeons

OBJECTIVES

A project to assess the existing literature and the quality of past guidelines on the management of primary spontaneous pneumothorax was developed by the Italian Society of Thoracic Surgeons, with particular focus on the assessment of the methods used to produce such recommendations.

METHODS

The different items and domains within each guideline were assessed using the Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument and scored on a 7-point scale.

RESULTS

Five guidelines matched the inclusion criteria and were assessed. A multinational collaboration produced 2 of 5 guidelines. The observers recommended (with modifications) only 2 guidelines. Clarity of presentation, scope and purpose (objectives and health questions target the population) received the best score, whereas the applicability of the guideline received the lowest score. International development positively influenced the scope and purpose of the guidelines. Moreover, improved scores were achieved when the stakeholders were fully involved and had editorial independence.

CONCLUSIONS

As assessed by the AGREE II criteria, the quality of the various guidelines was extremely inconsistent. Guidelines with higher AGREE II scores were those developed with the participation of European scientific societies.

Association Between Ambient Air Pollution Exposure and Spontaneous Pneumothorax Occurrence

BACKGROUND

Spontaneous pneumothorax is hypothesized to be associated with air pollution exposure based on pathophysiological mechanisms involving airway inflammation. Therefore, we analyzed the association between daily concentrations of air pollutants [sulfur dioxide, nitrogen dioxide (NO2), carbon monoxide (CO), ozone (O3), particulate matter (PM) less than 2.5 μm in diameter (PM2.5), PM less than 10 μm in diameter (PM10), and coarse PM (PM10-2.5)] and the number of spontaneous pneumothorax-related hospital visits.

METHODS

We analyzed a subset of data from the National Health Insurance Service-National Sample Cohort, a nationally representative dynamic cohort based on health insurance claims data in Korea. Using time series analysis with the Poisson generalized additive model, we evaluated hospital visit data of over 100,000 male cohort members residing in Seoul from 2007 to 2010.

RESULTS

We identified 516 hospital visits due to spontaneous pneumothorax. In a single-pollutant model, an interquartile range increase of PM and CO exposure at lag day 1 was associated with spontaneous pneumothorax hospital visits (relative risk, 95% confidence interval: PM2.5: 1.10 (1.01, 1.21); PM10: 1.09 (1.01, 1.18); PM10-2.5: 1.06 (1.00, 1.12); CO: 1.11 (1.01, 1.23)). For lag day 2, NO2 and PM exposure was associated with pneumothorax hospital visits (NO2: 1.15 (1.01, 1.32); PM10: 1.10 (1.02, 1.18); PM10-2.5: 1.07 (1.02, 1.13)). In a multipollutant model, the association was consistent for PM.

CONCLUSION

The number of hospital visits due to spontaneous pneumothorax increased with air pollution exposure, especially with PM. Our finding suggests that air pollution is a possible predisposing factor for spontaneous pneumothorax.

The accuracy of computed tomography in detecting surgically resectable blebs or bullae in primary spontaneous pneumothorax

OBJECTIVES

Chest computed tomography is commonly used in patients with primary spontaneous pneumothorax to detect the presence of pulmonary blebs or bullae. The aim of this study is to calculate the accuracy of chest computed tomography to detect surgically resectable blebs or bullae in patients with primary spontaneous pneumothorax.

METHODS

This is a retrospective study includes all patients with primary spontaneous pneumothorax who underwent chest computed tomography evaluation for their disease over the period from January 2005 to December 2015. Patients who underwent surgical exploration were sub-grouped to calculate the sensitivity and the specificity of the chest computed tomography to detect surgically resectable pulmonary blebs or bullae.

RESULTS

A total of 143 patients were included in the study. Among them, 120 patients underwent surgical exploration with the finding of 95.7% sensitivity and 42.3% specificity for the chest computed tomography in detection of surgically resectable pulmonary blebs or bullae.

CONCLUSION

The sensitivity of the chest computed tomography scan is high in detecting surgically resectable pulmonary blebs or bullae. However, the specificity is low. This may lead to overdiagnosis of the patients to have pulmonary blebs and bullae. Therefore, the routine use of chest computed tomography scan before the surgical exploration in patients with primary spontaneous pneumothorax should depend on the clinical judgment.

Management of Primary Spontaneous Pneumothorax: A Single-center Experience

Background:

The prevalence of primary spontaneous pneumothorax is high in the Arab region. There is a lack of studies from the Eastern Province of Saudi Arabia highlighting the associated risk factors and demonstrating the effectiveness of surgical management.

Objectives:

To identify risk factors associated with primary spontaneous pneumothorax and to correlate the effectiveness of surgical management with the rate of disease recurrence.

Subjects and Methods:

This retrospective chart review included adult patients who presented with primary spontaneous pneumothorax and were managed at King Fahd Hospital of the University, Al-Khobar, Saudi Arabia, from January 1, 2005, to December 31, 2014. The results are presented as arithmetic mean for quantitative data, and chi-square test was used for statistical analysis. P ≤0.05 was considered statistically significant.

Results:

In total, 151 patients with primary spontaneous pneumothorax were included, with the majority being male (98.7%) and Saudis (88.7%). The mean age was 24 ± 6 years (range: 13–49 years), mean height 171 ± 8 cm (range: 144–193 cm) and mean body mass index 19.2 ± 3.8 kg/m² (range: 13.3–39.0 kg/m²). About 62% of the patients were smokers. Ten patients had an ipsilateral recurrence of primary spontaneous pneumothorax after the first episode was successfully managed. Surgical exploration after the first episode itself was found to significantly reduce the recurrence rate. The study found that in the management of these patients, there was a shift from conventional open thoracotomy to the minimally invasive video-assisted thoracoscopic surgery method.

Conclusions:

The risk factors for primary spontaneous pneumothorax in this study were consistent with the current literature. Surgical exploration after the first episode of primary spontaneous pneumothorax significantly reduces the recurrence rate and there is a paradigm shift toward a less invasive surgical approach in managing these patients.

Will the presence of radiological signs of tension pneumothorax affect the clinical presentation of primary spontaneous pneumothorax?

INTRODUCTION

Patients with primary spontaneous pneumothorax (PSP) rarely presented with radiological signs of tension pneumothorax on their presenting chest X-ray. Even though, those patients may not develop the hemodynamic instability that is seen in tension pneumothorax. The aim of this study is to elaborate whether the presence of radiological signs of tension pneumothorax in patients with PSP will affect their clinical presentation.

METHODS

Retrospective study of all cases of PSP over a period from January 2007 to December 2014. The cases were divided into two groups; tension group includes cases who have radiological signs of tension pneumothorax and non-tension group who do not have those signs. The main outcome was a comparison of the hemodynamic status of both groups.

RESULTS

A total of 151 cases of PSP were included in the study. Radiologic signs of tension pneumothorax were identified in 13 cases of the sample. Only one case of the tension group developed hemodynamic instability in the form of desaturation to below 92% with no statistical difference between the two groups in maintaining the hemodynamic status.

CONCLUSION

In spite that PSP can be presented with radiological signs of tension pneumothorax, those patients usually maintained their hemodynamic stability. Tension pneumothorax rarely presented as consequence of PSP.

High Nrf2 expression in alveolar type I pneumocytes is associated with low recurrences in primary spontaneous pneumothorax

Recurrent primary spontaneous pneumothorax (PSP) is a troublesome problem and a major concern for the patients. This study examined whether nuclear factor erythroid 2-related factor 2 (Nrf2) expression in alveolar type I pneumocytes was associated with the clinical manifestations of PSP patients including disease recurrence. Eighty-eight PSP patients who were managed with needlescopic video-assisted thoracoscopic surgery (NVATS) were included in this study. Immunohistochemistry (IHC) was assessed to determine Nrf2 expression in resected lung tissues and the results were correlated with clinicopathological characteristics by the chi-square or the Fisher's exact test. The prognostic value of Nrf2 for overall recurrence was evaluated by univariate and multivariable Cox regression model. The expression of Nrf2 was observed in type I pneumocytes of lung tissues from PSP patients by IHC. We found that low Nrf2 expression in PSP patients, especially in young (age ≤ 20, p = 0.033) and body mass index (BMI) ≥18 kg/m² (p = 0.019) groups, was significantly correlated with PSP recurrence. In the univariate and multivariate analyses, high Nrf2 expression was a significant protective factor for overall recurrence in PSP patients (univariate: p = 0.026; multivariate: p = 0.004). The expression level of Nrf2 in alveolar type I pneumocytes was a potential factor involved in PSP recurrence. Our findings suggest that elevated Nrf2 expression in PSP patients may be a promising way for reducing PSP recurrence.

Novel clinical scoring system to identify patients with pneumothorax with suspicion for Birt-Hogg-Dubé syndrome

BACKGROUND AND OBJECTIVE

Birt-Hogg-Dubé syndrome (BHDS) is a rare hereditary disease that presents with multiple lung cysts and pneumothorax (PTX). Although some reports propose that findings from chest computed tomography enable one to distinguish BHDS from primary spontaneous pneumothorax (PSP), it is still unclear whether clinical features are useful for identifying patients with suspicion of BHDS from those with PTX.

METHODS

We retrospectively reviewed the medical records of patients with PTX who underwent video-assisted thoracoscopic surgery at Nissan Tamagawa Hospital from January 2012 to December 2015.

RESULTS

We identified a total of 1141 patients with PTX, including 54 with BHDS and 517 with PSP. Among them, logistic regression analysis segregated five features that were significantly associated with BHDS: familial history of PTX, past history of bilateral PTX, age at the first episode of PTX (≥25 years old (y.o.)), body mass index (≥18.5) and gender (female). We assigned scores of 3, 3, 2, 2 and 1 to the five features, respectively, to establish a system with a calculated score from 0 to 11. The cut-off value of a calculated score ≥ 4 yielded the highest sensitivity of 93% and specificity of 86%. Receiver operating characteristic (ROC) analysis showed the area under the curve reflecting an accuracy of this diagnostic test as 0.953.

CONCLUSION

BHDS has several clinical features distinct from PSP. Our scoring system consists of only five clinical variables that are easily evaluated and efficiently separate BHDS patients from those who have PTX without relying on an imaging study. Further prospective study is needed to confirm our findings.

Expression of redox sensing factor Nrf2 in lung macrophages and type II pneumocytes as a prognostic factor in pneumothorax recurrence

BACKGROUND

Primary spontaneous pneumothorax (PSP) is a common clinical problem. However, PSP recurrence is still a major concern. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays a protective role against oxidative airway diseases. The aim was to investigate the role of Nrf2 in PSP patients and its correlation with recurrence.

METHODS

Eighty-nine patients were enrolled and received wedge resection of lung with identifiable blebs. Nrf2 expression in resected lung tissues was determined by immunohistochemistry (IHC) and correlated with clinicopathological variables. The prognostic value of Nrf2 for incidence-of-recurrence was determined by Kaplan-Meier estimates and the significance of differences was evaluated by the log-rank test.

RESULTS

Nrf2 staining was predominantly observed in alveolar macrophages and type II pneumocytes of PSP patients and correlated with recurrence (P<0.001 and P=0.001, respectively) and PSP location (macrophages, P=0.013). High Nrf2 expression was correlated with better incidence-of-recurrence (macrophages, P=0.003; type II pneumocytes, P=0.003). Moreover, incidence-of-recurrence was better in patients with higher Nrf2 expression, especially those in the age ≤20, male, and non-smoking groups (macrophages, P=0.009, 0.006, and 0.012; type II pneumocytes, P=0.003, 0.011, and 0.010, respectively).

CONCLUSIONS

High Nrf2 expression in alveolar macrophages and type II pneumocytes was significantly associated with the decreased recurrence risk and was the independent factor predicting a better incidence-of-recurrence in PSP. Our results suggest that Nrf2 activation in high risk patients may be a potential target for reducing PSP recurrence.

Simple aspiration versus intercostal tube drainage for primary spontaneous pneumothorax in adults

BACKGROUND

For management of pneumothorax that occurs without underlying lung disease, also referred to as primary spontaneous pneumothorax, simple aspiration is technically easier to perform than intercostal tube drainage. In this systematic review, we seek to compare the clinical efficacy and safety of simple aspiration versus intercostal tube drainage for management of primary spontaneous pneumothorax. This review was first published in 2007 and was updated in 2017.

OBJECTIVES

To compare the clinical efficacy and safety of simple aspiration versus intercostal tube drainage for management of primary spontaneous pneumothorax.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 1) in the Cochrane Library; MEDLINE (1966 to January 2017); and Embase (1980 to January 2017). We searched the World Health Organization (WHO) International Clinical Trials Registry for ongoing trials (January 2017). We checked the reference lists of included trials and contacted trial authors. We imposed no language restrictions.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) of adults 18 years of age and older with primary spontaneous pneumothorax that compared simple aspiration versus intercostal tube drainage.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, assessed trial quality, and extracted data. We combined studies using the random-effects model.

MAIN RESULTS

Of 2332 publications obtained through the search strategy, seven studies met the inclusion criteria; one study was ongoing and six studies of 435 participants were eligible for inclusion in the updated review. Data show a significant difference in immediate success rates of procedures favouring tube drainage over simple aspiration for management of primary spontaneous pneumothorax (risk ratio (RR) 0.78, 95% confidence interval (CI) 0.69 to 0.89; 435 participants, 6 studies; moderate-quality evidence). Duration of hospitalization however was significantly less for patients treated by simple aspiration (mean difference (MD) -1.66, 95% CI -2.28 to -1.04; 387 participants, 5 studies; moderate-quality evidence). A narrative synthesis of evidence revealed that simple aspiration led to fewer adverse events (245 participants, 3 studies; low-quality evidence), but data suggest no differences between groups in terms of one-year success rate (RR 1.07, 95% CI 0.96 to 1.18; 318 participants, 4 studies; moderate-quality evidence), hospitalization rate (RR 0.60, 95% CI 0.25 to 1.47; 245 participants, 3 studies; very low-quality evidence), and patient satisfaction (median between-group difference of 0.5 on a scale from 1 to 10; 48 participants, 1 study; low-quality evidence). No studies provided data on cost-effectiveness.

AUTHORS' CONCLUSIONS

Available trials showed low to moderate-quality evidence that intercostal tube drainage produced higher rates of immediate success, while simple aspiration resulted in a shorter duration of hospitalization. Although adverse events were reported more commonly for patients treated with tube drainage, the low quality of the evidence warrants caution in interpreting these findings. Similarly, although this review observed no differences between groups when early failure rate, one-year success rate, or hospital admission rate was evaluated, this too needs to be put into the perspective of the quality of evidence, specifically, for evidence of very low and low quality for hospitalization rate and patient satisfaction, respectively. Future adequately powered research is needed to strengthen the evidence presented in this review.

Body surface area is a novel predictor for surgical complications following video-assisted thoracoscopic surgery for lung adenocarcinoma: a retrospective cohort study

Background

Body surface area (BSA) is a biometric unit to measure the body size. Its clinical significance in video-assisted thoracoscopic surgery (VATS) was rarely understood. We aimed to estimate the predictive value of BSA for surgical complications following VATS anatomical resections for lung adenocarcinoma (LAC).

Methods

A single-center retrospective analysis was performed on the consecutive patients between July 2014 and January 2016 in our institution. The differences in mean BSA values were evaluated between groups of patients classified by the development of postoperative surgical complications (PSCs), overall morbidity and cardiopulmonary complications, respectively. Receiver operating characteristic (ROC) analysis was performed to determine a threshold value of BSA on prediction of PSC occurrence. A multivariate logistic-regression model involving this optimal cut-off value and other significant parameters was established to identify the predictors for PSCs.

Results

During the study period, a total of 442 patients undergoing VATS anatomical resections for LAC were enrolled in this study. There were 135 patients developed with one or more complications (rate = 30.5%). PSCs occupied the largest percentages of all these complications (n = 81, rate = 18.3%). The mean BSA in PSC group was significantly higher than that in non-PSC group (1.76 ± 0.15 m² vs 1.71 ± 0.16 m²; P = 0.016). No difference was found in mean BSA values between groups classified by any other complication. The ROC analysis determined a BSA value of 1.68 m² to be the threshold value with the maximum joint sensitivity of 72.8% and specificity of 48.5%. Compared to patients with BSA ≤ 1.68 m², patients with BSA > 1.68 m² had significantly higher incidences of prolonged air leak (P = 0.006) and chylothorax (P = 0.004). Further multivariate logistic-regression analysis indicated that BSA > 1.68 m² could be an independent risk factor for PSCs (odds ratio: 2.03; P = 0.025).

Conclusions

BSA is an excellent categorical predictor for surgical complications following VATS anatomical resections for LAC. It may be considered when informing patients about surgical risks and selecting cases in the early learning curve. Large-scale and multi-institutional studies are expected to confirm and modify our findings in the future.

Electronic supplementary material

The online version of this article (doi:10.1186/s12893-017-0264-4) contains supplementary material, which is available to authorized users.

Association of MMP-2 and MMP-9 expression with recurrences in primary spontaneous pneumothorax

Primary spontaneous pneumothorax (PSP) is a common benign problem. However, PSP recurrence is still a troublesome complication for most patients. This study intended to determine the role of matrix metalloproteinase-2 (MMP-2) and MMP-9 in type II pneumocytes of patients with PSP and its relation with recurrence. Ninety-one patients who had undergone needlescopic video-assisted thoracoscopic surgery wedge resection of lung with identifiable blebs for PSP were included in this study. Immunohistochemical (IHC) staining was used to measure the expression of MMP-2 and MMP-9 in lung tissues of PSP patients. The results were further correlated with clinicopathological parameters and recurrence rates using chi-square or Fisher's exact test. The value of MMP-2 and MMP-9 for overall recurrence was analyzed by univariate and multivariable Cox regression model. IHC data revealed that MMP-2 and MMP-9 staining was predominantly observed in type II pneumocytes of patients with PSP. We found that MMP-2 and MMP-9 expression in PSP, especially male PSP patients, was significantly correlated with recurrence. In the univariate and multivariate analyses, MMP-2 and MMP-9 were statistically significant risk factors for overall recurrence in PSP patients. Therefore, high expression levels of MMP-2 and MMP-9 in type II pneumocytes show a positive correlation with PSP recurrence risk. Further studies are needed to validate whether reduction of MMP-2 and MMP-9 expression may be a promising way for decreasing the risk of PSP recurrence in the future.

Abnormal bone mineral density and bone turnover marker expression profiles in patients with primary spontaneous pneumothorax

BACKGROUND

To examine the bone mineral density (BMD) and the role of bone biomarkers, including bone formation marker procollagen type I aminoterminal propeptide (PINP) and N-terminal midmolecule fragment osteocalcin (N-MID), bone resorption marker b-C-telopeptides of type I collagen (b-CTX) and tartrate-resistant acid phosphatase 5b (TRACP5b) in the pathogenesis of PSP.

METHODS

Eighty-three consecutive primary spontaneous pneumothorax (PSP) patients (PSP group) and 87 healthy individuals (control group) were enrolled in this study. General data, including gender, age, height, weight, and body mass index (BMI), were recorded. Dual-energy X-ray absorptiometry, electrochemiluminescence immunoassay (ECLIA), and ELISA were used to evaluate bone mineral density and expression levels of bone metabolism markers, including PINP, b-CTX, TRACP5b, N-MID, and 25-hydroxyvitamin D (25-OH VD).

RESULTS

Mean height was significantly greater in the PSP group compared with the control group, whereas weight and BMI were lower. Patients in the PSP group had significantly lower average bone mineral density, which mainly manifested as osteopenia (11/12, 91.7%); however, only one patient (8.3%) developed osteoporosis. Serum overexpression of PINP, b-CTX, TRACP5b, and N-MID were found in PSP patients. Expression of 25-OH VD was low in PSP patients. Bone resorption markers showed positive linear relationships with bone formation markers in all participants; whereas only TRACP5b expression negatively correlated with 25-OH VD. Expression levels of all bone turnover markers negatively correlated with BMI. Regression analysis identified risk factors of PSP as age, height, weight, and TRACP5b and 25-OH VD expression levels; whereas gender and PINP, b-CTX, and N-MID expression levels were not significantly associated with the onset of PSP.

CONCLUSIONS

It had lower bone mineral density in PSP patients. Bone formation marker PINP, N-MID and bone resorption marker b-CTX, TRACP5b were upregulated in PSP patients. 25-OH VD expression was relatively low in this population of PSP patients. Age, height, weight, and expression levels of TRACP5b and 25-OH VD may be risk factors for PSP.

The effect of pleural abrasion on the treatment of primary spontaneous pneumothorax: a systematic review of randomized controlled trials

BACKGROUND

Pleural abrasion has been widely used to control the recurrence of primary spontaneous pneumothorax (PSP). However, controversy still exists regarding the advantages and disadvantages of pleural abrasion compared with other interventions in preventing the recurrence of PSP.

METHODS

The PubMed, Embase, and Cochrane Central Register of Controlled Trials databases were searched up to December 15, 2014 to identify randomized controlled trials (RCTs) that compared the effects of pleural abrasion with those of other interventions in the treatment of PSP. The study outcomes included the PSP recurrence rate and the occurrence rate of adverse effects.

RESULTS

Mechanical pleural abrasion and apical pleurectomy after thoracoscopic stapled bullectomy exhibited similarly persistent postoperative air leak occurrence rates (p = 0.978) and 1-year PSP recurrence rates (p = 0.821), whereas pleural abrasion led to reduced residual chest pain and discomfort (p = 0.001) and a smaller rate of hemothorax (p = 0.036) than did apical pleurectomy. However, the addition of minocycline pleurodesis to pleural abrasion did not reduce the pneumothorax recurrence rate compared with apical pleurectomy (3.8% for both procedures) but was associated with fewer complications. There was no statistical difference in the pneumothorax recurrence rate between mechanical pleural abrasion and chemical pleurodesis with minocycline on either an intention-to-treat basis (4 of 42 versus 0 of 42, p = 0.12; Fisher exact test) or after exclusions (2 of 40 versus 0 of 42, p = 0.24; Fisher exact test). Pleural abrasion plus minocycline pleurodesis also did not reduce the pneumothorax recurrence rate compared with pleural abrasion alone (p = 0.055). Moreover, pleural abrasion plus minocycline pleurodesis was associated with more intense acute chest pain. The postoperative overall recurrence rate in patients who underwent staple line coverage with absorbable cellulose mesh and fibrin glue was similar to that with mechanical abrasion after thoracoscopic bullectomy (13.8% vs. 14.2%, respectively; p = 0.555), but staple line coverage resulted in less postoperative residual pain than mechanical abrasion (0.4% vs.3.2%; p<0.0001). Pleural abrasion after thoracoscopic wedge resection did not decrease the recurrence of pneumothorax compared with wedge resection alone (p = 0.791), but the intraoperative bleeding and postoperative pleural drainage rates were higher when pleural abrasion was performed.

CONCLUSIONS

In addition to resulting in the same pneumothorax recurrence rate, thoracoscopic pleural abrasion with or without minocycline pleurodesis is safer than apical pleurectomy in the treatment of PSP. However, minocycline pleurodesis with or without pleural abrasion is not any more effective than pleural abrasion alone. Moreover, additional mechanical abrasion is not safer than additional staple line coverage with absorbable cellulose mesh and fibrin glue after thoracoscopic bullectomy because of increased postoperative pain. Additionally, pleural abrasion after thoracoscopic wedge resection should not be recommended for routine application due to the greater incidence of adverse effects than wedge resection alone. However, further large-scale, well-designed RCTs are needed to confirm the best procedure.

FLCN intragenic deletions in Chinese familial primary spontaneous pneumothorax

Primary spontaneous pneumothorax (PSP) is a significant clinical problem, affecting tens of thousands patients annually. Germline mutations in the FLCN gene have been implicated in etiology of familial PSP (FPSP). Most of the currently identified FLCN mutations are small indels or point mutations that detected by Sanger sequencing. The aim of this study was to determine large FLCN deletions in PSP families that having no FLCN sequence-mutations. Multiplex ligation-dependent probe amplification (MLPA) assays and breakpoint analyses were used to detect and characterize the deletions. Three heterozygous FLCN intragenic deletions were identified in nine unrelated Chinese families including the exons 1-3 deletion in two families, the exons 9-14 deletion in five families and the exon 14 deletion in two families. All deletion breakpoints are located in Alu repeats. A 5.5 Mb disease haplotype shared in the five families with exons 9-14 deletion may date the appearance of this deletion back to approximately 16 generations ago. Evidences for founder effects of the other two deletions were also observed. This report documents the first identification of founder mutations in FLCN, as well as expands mutation spectrum of the gene. Our findings strengthen the view that MLPA analysis for intragenic deletions/duplications, as an important genetic testing complementary to DNA sequencing, should be used for clinical molecular diagnosis in FPSP.

Pneumothorax: a tale of pain or spontaneity

Pneumothoraces may be due a variety of aetiologies. Here we present two different cases: one with a unilateral pneumothorax due an iatrogenic medical procedure and another of idiopathic spontaneous bilateral nature. Although both cases were initially managed conservatively, the latter case required surgical intervention. We also conduct a literature review of the aetiology and management of pneumothoraces.

Overexpression of matrix metalloproteinases in lung tissue of patients with primary spontaneous pneumothorax

BACKGROUND

Although blebs and bullae are frequently found in the apexes of lungs of patients with primary spontaneous pneumothorax (PSP), its pathogens remain unclear.

OBJECTIVES

To examine the role of proteases [matrix metalloproteinase (MMP)-2, MMP-7 and MMP-9] and antiproteases [tissue inhibitors of metalloproteinase (TIMP)-1, TIMP-2, TIMP-3 and TIMP-4] in the pathogenesis of PSP.

METHOD

Fifty consecutive PSP patients who received standard surgical care were enrolled in the study. Lung tissues from 20 patients with stage I non-small cell lung cancer were used as a control. Immunohistochemistry (IHC), reverse transcription-polymerase chain reaction (RT-PCR) and gelatin zymography were used to evaluate the expression of MMP and TIMP in the lung tissue of patients with PSP.

RESULTS

Overexpression of MMP-2, MMP-7 and MMP-9 was found in the afflicted lung by IHC, zymography and RT-PCR. By IHC, higher expression of MMP-2 and MMP-9 in PSP patients was identified in alveolar macrophages and type II pneumocytes (88 and 92% of patients in macrophages, and 72 and 70% of patients in type II pneumocytes, respectively). MMP-2, MMP-7 and MMP-9 expression in patients was higher in mesothelial cells (66, 76 and 76%). Overexpression of TIMP-2 was detected in the extracellular matrix around bullae and blebs. Expression levels of TIMP-1, TIMP-3 and TIMP-4 were negligible (<10% of cells) in both PSP patients and controls.

CONCLUSIONS

MMP-2, MMP-9, MMP-7 and TIMP-2 were upregulated in PSP lesions. These results suggest that an imbalance between the expression of proteases and antiproteases may be involved in the pathogeneses of PSP.

Propofol versus midazolam in medical thoracoscopy: a randomized, noninferiority trial

BACKGROUND

Hypoxemia is a surrogate marker for periprocedural endoscopic complications. There are no data comparing the safety of propofol sedation with another sedative regimen in medical thoracoscopy.

OBJECTIVE

To evaluate whether sedation with propofol is as safe and effective as sedation with midazolam.

METHODS

Ninety consecutive patients undergoing medical thoracoscopy were randomly allocated to receive either intravenous propofol or midazolam. Predefined periprocedural complications included hypoxemia, hypotension, bleeding, need for airway insertion, mechanical ventilation, intensive care unit transfer and death. The primary endpoint was the mean lowest oxygen saturation during the procedure.

RESULTS

Randomized groups had similar demographics (64 ± 16 years, 57% male, 91% American Society of Anesthesiologists class III-IV) and a balanced distribution of procedures. The mean lowest oxygen saturation during the procedure was significantly lower in the propofol group as compared to the midazolam group (93 ± 6 vs. 96 ± 3%, p = 0.007). Patients randomized to propofol showed more episodes of hypoxemia (27 vs. 4%, p = 0.007) and hypotension (82 vs. 40%, p < 0.0001). No procedure had to be aborted. None of the patients required an artificial airway, mechanical ventilation or intensive care unit care, and none died.

CONCLUSIONS

As assessed by the surrogate marker hypoxemia, propofol should not be considered the first choice for sedation in medical thoracoscopy.

A de novo FLCN mutation in a patient with spontaneous pneumothorax and renal cancer; a clinical and molecular evaluation

Birt-Hogg-Dubé syndrome (BHD) is an autosomal dominant condition due to germline FLCN (folliculin) mutations, characterized by skin fibrofolliculomas, lung cysts, pneumothorax and renal cancer. We identified a de novo FLCN mutation, c.499C>T (p.Gln167X), in a patient who presented with spontaneous pneumothorax. Subsequently, typical skin features and asymptomatic renal cancer were diagnosed. Probably, de novo FLCN mutations are rare. However, they may be under-diagnosed if BHD is not considered in sporadic patients who present with one or more of the syndromic features. Genetic and immunohistochemical analysis of the renal tumour indicated features compatible with a tumour suppressor role of FLCN. The finding that mutant FLCN was expressed in the tumour might indicate residual functionality of mutant FLCN, a notion which will be explored in future studies.

Thoracic emergencies

This article discusses thoracic emergencies, including the anatomy, pathophysiology, clinical presentation, examination, diagnosis, technique, management, and treatment of acute upper airway obstruction, massive hemoptysis, spontaneous pneumothorax, and pulmonary empyema.

Pneumothorax, music and balloons: A case series

We describe two cases of spontaneous pneumothorax in young healthy adults with no underlying structural lung disease. The onset of pneumothorax was following physical activity including playing musical instruments and blowing of balloons. There is sparse data evaluating the pathophysiology of primary spontaneous pneumothorax in relation to increased mouth pressures. These cases highlight the possible physical effect of valsalva manoeuvre on transpulmonary pressures, and the potential risk of developing pneumothorax in otherwise healthy individuals. This aspect of pneumothorax development is worthy of further exploration, to better elucidate the mechanism and enhance our understanding of this common respiratory presentation.

A unique, histopathologic lesion in a subset of patients with spontaneous pneumothorax

CONTEXT

Spontaneous pneumothorax can be idiopathic (primary), or it can occur in association with an underlying predisposing condition (secondary). Spontaneous pneumothorax may be a harbinger of an undiagnosed clinical condition, which may be associated with serious systemic abnormalities, making early recognition and diagnosis important. The pulmonary pathology of some of these disorders has not been fully elucidated.

OBJECTIVE

To review cases of pneumothorax in the hope of identifying pathologic features that might correlate to specific clinical syndromes.

DESIGN

The pathology computer files at 3 hospitals were searched for all cases of spontaneous pneumothorax, primary and secondary, regardless of etiology during a 11-year period. Ninety-two cases were retrieved. Each of the cases was evaluated for reactive eosinophilic pleuritis, elastosis, pleural fibrosis, emphysema, intra-alveolar macrophages, cholesterol clefts, vasculopathy, and intraparenchymal or intrapleural cysts. Clinical information regarding asthma and smoking history, site of the pneumothorax, family history, radiographic findings, predisposing conditions, recurrence, age, and sex were extracted from the medical records.

RESULTS

In 11 patients (12% of all the patients with spontaneous pneumothorax), a distinctive pattern of pleural fibrosis with islands of fibroblastic foci within a myxoid stroma was noted at the pleural-parenchymal interface or leading edge. These lesions correlated with a select subset of patients, consisting predominantly of young men.

CONCLUSIONS

Our review identified a distinct pattern of pneumothorax-associated fibroblastic lesions in a subset of cases of spontaneous pneumothorax. Whether this is related to the pathogenesis of the pneumothorax remains to be elucidated.

Emergencies in pleural diseases

A parapneumonic effusion should be drained if it is large (≥ 1/2 of the hemithorax), loculated, frank pus is obtained, if the fluid is non-purulent fluid but has a low pH (< 7.20) or if the culture is positive. Instillation of fibrinolytics and DNase thorough the chest catheter in locutated effusions and empyemas is currently recommended. Management of spontaneous pneumothorax is fundamentally influenced by the patient's symptoms. Insertion of a chest catheter is mandatory if there is significant dyspnea, hemodynamic instability or large pneumothoraces (≥ 2 cm). Pleural ultrasonography confirms the presence of air or fluid in the pleural space and serves to guide any pleural procedure (e.g., thoracentesis, chest tubes). The use of small-bore 12F catheters inserted via the percutaneous Seldinger technique under ultrasonography guidance is a safe and effective procedure in complicated parapneumonic effusions/empyema and most pneumothoraces.

Spontaneous recovery of ventilator-associated pneumothorax

BACKGROUND

The usual management of ventilator-associated pneumothorax (VPX) is tube thoracostomy. However, this recommendation is based on tradition rather than on solid evidence. Although it has been applied successfully to other types of pneumothoraces, observation has not been used in the management of VPX.

OBJECTIVES

In this study, we investigated whether observation is a valid treatment strategy for VPX.

METHODS

We retrospectively analyzed data of 471 patients with VPX (2003-2010) and found that 27 did not receive tube thoracostomy. Most of those patients (89%) had documented do-not-resuscitate orders and had refused tube thoracostomy. For comparison, 54 patients with tube thoracostomy, matched by age and do-not-resuscitate status, were chosen as controls. Among patients without tube thoracostomy, we compared attribute differences between those recovered and those not recovered.

RESULTS

Thirteen patients (48%) without tube thoracostomy experienced spontaneous recovery of their pneumothoraces. This rate of chest tube-free recovery was higher than that of patients with tube thoracostomy (48 vs. 17%; p = 0.003). The patients did not differ in in-hospital mortality rate, time to ventilator discontinuation or survival. By univariate logistic regression, spontaneous recovery was associated with VPX caused by needle puncture, lack of respiratory distress, large tidal volume and low oxygen requirement following pneumothorax, as well as by physician recommendation against intubation.

CONCLUSION

Observation under physician surveillance is an effective option of managing many VPXs, especially those caused by needle puncture, when patients are not in respiratory distress or when patients have acceptable tidal volumes and oxygen requirements following pneumothorax.