Diagnosis of cystic lung diseases: a position statement from the UK Cystic Lung Disease Rare Disease Collaborative Network.

BACKGROUND: Rare cystic lung diseases are increasingly recognised due the wider application of CT scanning making cystic lung disease management a growing part of respiratory care. Cystic lung diseases tend to have extrapulmonary features that can both be diagnostic but also require surveillance and treatment in their own right. As some of these diseases now have specific treatments, making a precise diagnosis is crucial. While Langerhans cell histiocytosis, Birt-Hogg-Dubé syndrome, lymphoid interstitial pneumonia and lymphangioleiomyomatosis are becoming relatively well-known diseases to respiratory physicians, a targeted and thorough workup improves diagnostic accuracy and may suggest other ultrarare diseases such as light chain deposition disease, cystic pulmonary amyloidosis, low-grade metastatic neoplasms or infections. In many cases, diagnostic information is overlooked leaving uncertainty over the disease course and treatments. AIMS: This position statement from the Rare Disease Collaborative Network for cystic lung diseases will review how clinical, radiological and physiological features can be used to differentiate between these diseases. NARRATIVE: We highlight that in many cases a multidisciplinary diagnosis can be made without the need for lung biopsy and discuss where tissue sampling is necessary when non-invasive methods leave diagnostic doubt. We suggest an initial workup focusing on points in the history which identify key disease features, underlying systemic and familial diseases and a clinical examination to search for connective tissue disease and features of genetic causes of lung cysts. All patients should have a CT of the thorax and abdomen to characterise the pattern and burden of lung cysts and extrapulmonary features and also spirometry, gas transfer and a 6 min walk test. Discussion with a rare cystic lung disease centre is suggested before a surgical biopsy is undertaken. CONCLUSIONS: We suggest that this focused workup should be performed in all people with multiple lung cysts and would streamline referral pathways, help guide early treatment, management decisions, improve patient experience and reduce overall care costs. It could also potentially catalyse a national research database to describe these less well-understood and unidentified diseases, categorise disease phenotypes and outcomes, potentially leading to better prognostic data and generating a stronger platform to understand specific disease biology.

Pulmonary sarcoidosis: differences in lung function change over time.

INTRODUCTION: Given the heterogeneity of sarcoidosis, predicting disease course of patients remains a challenge. Our aim was to determine whether the 3-year change in pulmonary function differed between pulmonary function phenotypes and whether there were differential longitudinal changes by race and sex. METHODS: We identified individuals seen between 2005 and 2015 with a confirmed diagnosis of sarcoidosis who had at least two pulmonary function test measurements within 3 years of entry into the cohort. For each individual, spirometry, diffusion capacity, Charlson Comorbidity Index, sarcoidosis organ involvement, diagnosis duration, tobacco use, race, sex, age and medications were recorded. We compared changes in pulmonary function by type of pulmonary function phenotype and for demographic groups. RESULTS: Of 291 individuals, 59% (173) were female and 54% (156) were black. Individuals with restrictive pulmonary function phenotype had significantly greater 3-year rate of decline of FVC% (forced vital capacity) predicted and FEV1% (forced expiratory volume in 1 s) predicted course when compared with normal phenotype. We identified a subset of individuals in the cohort, highest decliners, who had a median 3-year FVC decline of 156 mL. Black individuals had worse pulmonary function at entry into the cohort measured by FVC% predicted, FEV1% predicted and diffusing capacity for carbon monoxide % predicted compared with white individuals. Black individuals' pulmonary function remained stable or declined over time, whereas white individuals' pulmonary function improved over time. There were no sex differences in rate of change in any pulmonary function parameters. SUMMARY: We found significant differences in 3-year change in pulmonary function among pulmonary function phenotypes and races, but no difference between sexes.

Survival analysis from the INCREASE study in PH-ILD: evaluating the impact of treatment crossover on overall mortality.

OBJECTIVE: A post-hoc analysis of the INCREASE trial and its open-label extension (OLE) was performed to evaluate whether inhaled treprostinil has a long-term survival benefit in patients with pulmonary hypertension associated with interstitial lung disease (PH-ILD). METHODS: Two different models of survival were employed; the inverse probability of censoring weighting (IPCW) and the rank-preserving structural failure time (RPSFT) models both allow construction of a pseudo-placebo group, thereby allowing for long-term survival evaluation of patients with PH-ILD receiving inhaled treprostinil. Time-varying stabilised weights were calculated by fitting Cox proportional hazards models based on the baseline and time-varying prognostic factors to generate weighted Cox regression models with associated adjusted HRs. RESULTS: In the INCREASE trial, there were 10 and 12 deaths in the inhaled treprostinil and placebo arms, respectively, during the 16-week randomised trial. During the OLE, all patients received inhaled treprostinil and there were 29 and 33 deaths in the prior inhaled treprostinil arm and prior placebo arm, respectively. With a conventional analysis, the HR for death was 0.71 (95% CI 0.46 to 1.10; p=0.1227). Both models demonstrated significant reductions in death associated with inhaled treprostinil treatment with HRs of 0.62 (95% CI 0.39 to 0.99; p=0.0483) and 0.26 (95% CI 0.07 to 0.98; p=0.0473) for the IPCW and RPSFT methods, respectively. CONCLUSION: Two independent modelling techniques that have been employed in the oncology literature both suggest a long-term survival benefit associated with inhaled treprostinil treatment in patients with PH-ILD.

Monocyte NLRP3 inflammasome and interleukin-1ß activation modulated by alpha-1 antitrypsin therapy in deficient individuals.

INTRODUCTION: Altered complement component 3 (C3) activation in patients with alpha-1 antitrypsin (AAT) deficiency (AATD) has been reported. To understand the potential impact on course of inflammation, the aim of this study was to investigate whether C3d, a cleavage-product of C3, triggers interleukin (IL)-1ß secretion via activation of NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome. The objective was to explore the effect of AAT augmentation therapy in patients with AATD on the C3d/complement receptor 3 (CR3) signalling axis of monocytes and on circulating pro-inflammatory markers. METHODS: Inflammatory mediators were detected in blood from patients with AATD (n=28) and patients with AATD receiving augmentation therapy (n=19). Inflammasome activation and IL-1ß secretion were measured in monocytes of patients with AATD, and following C3d stimulation in the presence or absence of CR3 or NLRP3 inhibitors. RESULTS: C3d acting via CR3 induces NLRP3 and pro-IL-1ß production, and through induction of endoplasmic reticulum (ER) stress and calcium flux, triggers caspase-1 activation and IL-1ß secretion. Treatment of individuals with AATD with AAT therapy results in decreased plasma levels of C3d (3.0±1.2 µg/mL vs 1.3±0.5 µg/mL respectively, p<0.0001) and IL-1ß (115.4±30 pg/mL vs 73.3±20 pg/mL, respectively, p<0.0001), with a 2.0-fold decrease in monocyte NLRP3 protein expression (p=0.0303), despite continued ER stress activation. DISCUSSION: These results provide strong insight into the mechanism of complement-driven inflammation associated with AATD. Although the described variance in C3d and NLRP3 activation decreased post AAT augmentation therapy, results demonstrate persistent C3d and monocyte ER stress, with implications for new therapeutics and clinical practice.

Prevalence of lung cysts in adolescents and adults with a germline DICER1 pathogenic/likely pathogenic variant: a report from the National Institutes of Health and International Pleuropulmonary Blastoma/DICER1 Registry.

BACKGROUND: Pleuropulmonary blastoma (PPB), the hallmark tumour associated with DICER1-related tumour predisposition, is characterised by an age-related progression from a cystic lesion (type I) to a high-grade sarcoma with mixed cystic and solid features (type II) or purely solid lesion (type III). Not all cystic PPBs progress; type Ir (regressed), hypothesised to represent regressed or non-progressed type I PPB, is an air-filled, cystic lesion lacking a primitive sarcomatous component. This study aims to evaluate the prevalence of non-progressed lung cysts detected by CT scan in adolescents and adults with germline DICER1 pathogenic/likely pathogenic (P/LP) variants. METHODS: Individuals were enrolled in the National Cancer Institute Natural History of DICER1 Syndrome study, the International PPB/DICER1 Registry and/or the International Ovarian and Testicular Stromal Tumor Registry. Individuals with a germline DICER1 P/LP variant with first chest CT at 12 years of age or older were selected for this analysis. RESULTS: In the combined databases, 110 individuals with a germline DICER1 P/LP variant who underwent first chest CT at or after the age of 12 were identified. Cystic lung lesions were identified in 38% (42/110) with a total of 72 cystic lesions detected. No demographic differences were noted between those with lung cysts and those without lung cysts. Five cysts were resected with four centrally reviewed as type Ir PPB. CONCLUSION: Lung cysts are common in adolescents and adults with germline DICER1 variation. Further study is needed to understand the mechanism of non-progression or regression of lung cysts in childhood to guide judicious intervention.

Epidemiology of childhood interstitial lung disease in France: the RespiRare cohort.

INTRODUCTION: Interstitial lung disease in children (chILD) are rare and mostly severe lung diseases. Very few epidemiological data are available in limited series of patients. The aim of this study was to assess the prevalence and incidence of chILD in France. METHODS: We performed within the RespiRare network a multicentre retrospective observational study in patients with chILD from 2000 to 2022 and a prospective evaluation of chILD's incidence between February 2022 and 2023. RESULTS: chILD was reported in 790 patients in 42 centres. The estimated 2022 prevalence in France was 44 /million children (95% CI 40.76 to 47.46) and the computed incidence was 4.4 /million children (95% CI 3.44 to 5.56). The median age at diagnosis was 3 months with 16.9% of familial forms. Lung biopsy and genetic analyses were performed in 23.4% and 76.9%, respectively. The most frequent chILD aetiologies in the <2 years group were surfactant metabolism disorders (16.3%) and neuroendocrine cell hyperplasia of infancy (11.8%), and in the 2-18 years group diffuse alveolar haemorrhage (12.2%), connective tissue diseases (11.4%), hypersensitivity pneumonitis (8.8%) and sarcoidosis (8.8%). The management included mainly oxygen therapy (52%), corticosteroid pulses (56%), oral corticosteroids (44%), azithromycin (27.2%), enteral nutrition (26.9%), immunosuppressants (20.3%) and hydroxychloroquine (15.9%). The 5-year survival rate was 57.3% for the patients diagnosed before 2 years and 86% between 2 and 18 years. CONCLUSION: This large and systematic epidemiological study confirms a higher incidence and prevalence of chILD than previously described. In order to develop international studies, efforts are still needed to optimise the case collection and to harmonise diagnostic and management practices.

Lymphangioleiomyomatosis as a potent lung cancer risk factor: Insights from a Japanese large cohort study.

BACKGROUND AND OBJECTIVE: Lymphangioleiomyomatosis (LAM) is a rare neoplastic disease associated with the functional tumour suppressor genes TSC1 and TSC2 and causes structural destruction in the lungs, which could potentially increase the risk of lung cancer. However, this relationship remains unclear because of the rarity of the disease. METHODS: We investigated the relative risk of developing lung cancer among patients diagnosed with LAM between 2001 and 2022 at a single high-volume centre in Japan, using data from the Japanese Cancer Registry as the reference population. Next-generation sequencing (NGS) was performed in cases where tumour samples were available. RESULTS: Among 642 patients diagnosed with LAM (sporadic LAM, n = 557; tuberous sclerosis complex-LAM, n = 80; unclassified, n = 5), 13 (2.2%) were diagnosed with lung cancer during a median follow-up period of 5.13 years. All patients were female, 61.5% were never smokers, and the median age at lung cancer diagnosis was 53 years. Eight patients developed lung cancer after LAM diagnosis. The estimated incidence of lung cancer was 301.4 cases per 100,000 person-years, and the standardized incidence ratio was 13.6 (95% confidence interval, 6.2-21.0; p = 0.0008). Actionable genetic alterations were identified in 38.5% of the patients (EGFR: 3, ALK: 1 and ERBB2: 1). No findings suggested loss of TSC gene function in the two patients analysed by NGS. CONCLUSION: Our study revealed that patients diagnosed with LAM had a significantly increased risk of lung cancer. Further research is warranted to clarify the carcinogenesis of lung cancer in patients with LAM.

Minimal important difference in childhood interstitial lung diseases.

BACKGROUND: Monitoring disease progression in childhood interstitial lung diseases (chILD) is essential. No information for the minimal important difference (MID), which is defined as the smallest change in a parameter that is perceived as important prompting a clinician to change the treatment, is available. We calculated MIDs for vital signs (respiratory rate, peripheral oxygen saturation in room air, Fan severity score) and health-related quality of life (HrQoL) scores. METHODS: This study used data from the Kids Lung Register, which is a web-based management platform that collects data of rare paediatric lung disorders with a focus on chILD. Data of vital signs and HrQoL scores (Health Status Questionnaire, chILD-specific questionnaire and PedsQL V.4.0) were collected. MIDs were calculated according to distribution-based (one-third SD) and anchor-based methods (using forced expiratory volume in 1 s and forced vital capacity) as anchors. RESULTS: Baseline data of 774 children were used to calculate the following MIDs: respiratory rate 1.3 (z-score), O2 saturation in room air 3.0%, Fan severity score 0.2-0.4, Health Status Questionnaire 0.4-0.8, chILD-specific questionnaire 4.4%-8.2%, physical health summary score 7.8%-8.9%, psychosocial health summary score 3.4%-6.9% and total score 5.1%-7.4%. Results of the responsiveness analysis generally agreed with the MIDs calculated. CONCLUSIONS: For the first time, we provide estimates of MIDs for vital signs and HrQoL scores in a large cohort of chILD using different methods.

Prognostic significance of radiological pleuroparenchymal fibroelastosis in Mycobacterium avium complex lung disease: a multicentre retrospective cohort study.

BACKGROUND: Mycobacterium avium complex (MAC) causes chronic respiratory infectious diseases with diverse clinical features and prognoses. Pleuroparenchymal fibroelastosis (PPFE) is a rare disease characterised by pleural fibrosis with subjacent intra-alveolar fibrosis and alveolar septal elastosis, with unique chest high-resolution CT (HRCT) features (radiological PPFE). An association between recurrent respiratory infections and PPFE formation has been hypothesised; however, the clinical significance of PPFE in MAC lung disease remains unclear. METHODS: This retrospective, multicentre study investigated the prevalence of radiological PPFE in patients with MAC lung disease and its association with clinical features and outcomes. Radiological PPFE was diagnosed on the basis of HRCT findings. Prognostic factors were identified using Cox proportional hazards and Fine-Gray models. RESULTS: Of 850 consecutive patients with definite MAC lung disease, 101 (11.9%) exhibited radiological PPFE. Patients with radiological PPFE had unique characteristics, such as lower body mass index, lower survival rate (5-year cumulative survival rate, 63.1% vs 91.7%; p<0.001) and a higher incidence of respiratory-related death (5-year cumulative incidence, 31.1% vs 3.6%; p<0.001), than those without radiological PPFE. In the multivariable analysis, the presence of radiological PPFE was independently associated with all-cause mortality (adjusted HR, 4.78; 95% CI, 2.87 to 7.95; p<0.001) and respiratory-related death (adjusted HR, 3.88; 95% CI, 2.14 to 7.01; p<0.001). INTERPRETATION: This large-scale study demonstrated that in patients with MAC lung disease, radiological PPFE was common, a phenotype associated with unique clinical features and poor prognosis, particularly respiratory-related death. The specific management of this subgroup should be established.

Cigarette smoking is a secondary cause of folliculin loss.

BACKGROUND: Birt-Hogg-Dubé syndrome (BHD) is a clinical syndrome manifesting with cystic lung disease and pneumothorax. Features of BHD result from the loss-of-function mutations of the folliculin (FLCN) gene. Chronic obstructive pulmonary disease (COPD), characterised by an irreversible airflow limitation, is primarily caused by cigarette smoking. OBJECTIVE: Given that COPD often shares structural features with BHD, we investigated the link between COPD, cigarette smoke (CS) exposure and FLCN expression. METHODS: We measured the expression of FLCN in human COPD lungs and CS-exposed mouse lungs, as well as in CS extract (CSE)-exposed immortalised human airway epithelial cells by immunoblotting. RESULTS: We found that the lung FLCN protein levels in smokers with COPD and CS exposure mice exhibit a marked decrease compared with smokers without COPD and room air exposure mice, respectively. We confirmed CS induced degradation of FLCN in immortalised human bronchial epithelial Beas-2B cells via ubiquitin proteasome system. Further, siRNA targeting FLCN enhanced CSE-induced cytotoxicity. By contrast, FLCN overexpression protected cells from CSE-induced cytotoxicity. We found that FBXO23, the ubiquitin E3 ligase subunit, specifically binds to and targets FLCN for degradation. Inhibition of ATM (ataxia-telangiectasia mutated) attenuated CSE induced FLCN degradation, suggesting a role of ATM in FLCN proteolysis. We further confirmed that the mutant of major FLCN phosphorylation site serine 62A is resistant to CSE-induced degradation and cytotoxicity. CONCLUSIONS: Our study demonstrates that CS exposure is a secondary cause of FLCN deficiency due to the enhanced proteolysis, which promoted airway epithelial cell death.

Lymphangioleiomyomatosis (LAM) Cell Atlas.

Lymphangioleiomyomatosis (LAM) is a rare lung disease of women, causing cystic remodelling of the lung and progressive respiratory failure. The cellular composition, microenvironment and cellular interactions within the LAM lesion remain unclear. To facilitate data sharing and collaborative LAM research, we performed an integrative analysis of single-cell data compiled from lung, uterus and kidney of patients with LAM from three research centres and developed an LAM Cell Atlas (LCA) Web-Portal. The LCA offers a variety of interactive options for investigators to search, visualise and reanalyse comprehensive single-cell multiomics data sets to reveal dysregulated genetic programmes at transcriptomic, epigenomic and cell-cell connectome levels.

ABCA3-related interstitial lung disease beyond infancy.

BACKGROUND: The majority of patients with childhood interstitial lung disease (chILD) caused by pathogenic variants in ATP binding cassette subfamily A member 3 (ABCA3) develop severe respiratory insufficiency within their first year of life and succumb to disease if not lung transplanted. This register-based cohort study reviews patients with ABCA3 lung disease who survived beyond the age of 1 year. METHOD: Over a 21-year period, patients diagnosed as chILD due to ABCA3 deficiency were identified from the Kids Lung Register database. 44 patients survived beyond the first year of life and their long-term clinical course, oxygen supplementation and pulmonary function were reviewed. Chest CT and histopathology were scored blindly. RESULTS: At the end of the observation period, median age was 6.3 years (IQR: 2.8-11.7) and 36/44 (82%) were still alive without transplantation. Patients who had never received supplemental oxygen therapy survived longer than those persistently required oxygen supplementation (9.7 (95% CI 6.7 to 27.7) vs 3.0 years (95% CI 1.5 to 5.0), p=0.0126). Interstitial lung disease was clearly progressive over time based on lung function (forced vital capacity % predicted absolute loss -1.1% /year) and on chest CT (increasing cystic lesions in those with repetitive imaging). Lung histology pattern were variable (chronic pneumonitis of infancy, non-specific interstitial pneumonia, and desquamative interstitial pneumonia). In 37/44 subjects, the ABCA3 sequence variants were missense variants, small insertions or deletions with in-silico tools predicting some residual ABCA3 transporter function. CONCLUSION: The natural history of ABCA3-related interstitial lung disease progresses during childhood and adolescence. Disease-modifying treatments are desirable to delay such disease course.

Pulmonary arteriovenous malformations may be the only clinical criterion present in genetically confirmed hereditary haemorrhagic telangiectasia.

Pulmonary arteriovenous malformations (PAVMs) result in preventable complications demanding specialty care. Underlying hereditary haemorrhagic telangiectasia (HHT) can be identified by genetic testing, if the diagnosis is considered. Retrospectively reviewing 152 unrelated adults with genetically confirmed HHT due to ACVRL1, ENG or SMAD4, we found that only 104/152 (68%) met a clinical diagnosis of HHT with three Curaçao criteria. The genetic diagnostic rate was similar for patients with three (104/137, 76%) or one to two (48/71, 68%; p=0.25) criteria. Of 83 unrelated probands with PAVM(s) and genetically-confirmed HHT, 20/83 (24%) had few, if any, features of HHT. Enhanced clinical suspicion, as well as HHT genetic testing, is recommended if one or more PAVMs are present.

Medical treatments for idiopathic pulmonary fibrosis: a systematic review and network meta-analysis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a respiratory disorder with a poor prognosis. Our objective is to assess the comparative effectiveness of 22 approved or studied IPF drug treatments. METHODS: We searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials and clinicaltrials.gov from inception to 2 April 2021. We included randomised controlled trials (RCTs) for adult patients with IPF receiving one or more of 22 drug treatments. Pairs of reviewers independently identified randomised trials that compared one or more of the target medical treatments in patients with IPF. We assessed the certainty of evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach for network meta-analysis. We calculated pooled relative risk (RR) ratios and presented direct or network estimates with 95% credibility intervals (95% CI), within the GRADE framework. RESULTS: We identified 48 (10 326 patients) eligible studies for analysis. Nintedanib [RR 0.69 (0.44 to 1.1), pirfenidone [RR 0.63 (0.37 to 1.09); direct estimate), and sildenafil [RR (0.44 (0.16 to 1.09)] probably reduce mortality (all moderate certainty). Nintedanib (2.92% (1.51 to 4.14)), nintedanib+sildenafil (157 mL (-88.35 to 411.12)), pirfenidone (2.47% (-0.1 to 5)), pamrevlumab (4.3% (0.5 to 8.1)) and pentraxin (2.74% (1 to 4.83)) probably reduce decline of overall forced vital capacity (all moderate certainty). Only sildenafil probably reduces acute exacerbation and hospitalisations (moderate certainty). Corticosteroids+azathioprine+N-acetylcysteine increased risk of serious adverse events versus placebo (high certainty). CONCLUSION AND RELEVANCE: Future guidelines should consider sildenafil for IPF and further research needs to be done on promising IPF treatments such as pamrevlumab and pentraxin as phase 3 trials are completed.

Effect of nusinersen on respiratory function in paediatric spinal muscular atrophy types 1-3.

INTRODUCTION: Nusinersen is used in spinal muscular atrophy (SMA) to improve peripheral muscle function; however, respiratory effects are largely unknown. AIM: To assess the effects of nusinersen on respiratory function in paediatric SMA during first year of treatment. METHODS: A prospective observational study in paediatric patients with SMA who began receiving nusinersen in Queensland, Australia, from June 2018 to December 2019. Outcomes assessed were the age-appropriate respiratory investigations: spirometry, oscillometry, sniff nasal inspiratory pressure, mean inspiratory pressure, mean expiratory pressure, lung clearance index, as well as polysomnography (PSG) and muscle function testing. Lung function was collected retrospectively for up to 2 years prior to nusinersen initiation. Change in lung function was assessed using mixed effects linear regression models, while PSG and muscle function were compared using the Wilcoxon signed-rank test. RESULTS: Twenty-eight patients (15 male, aged 0.08-18.58 years) were enrolled: type 1 (n=7); type 2 (n=12); type 3 (n=9). The annual rate of decline in FVC z-score prior to nusinersen initiation was -0.58 (95% CI -0.75 to -0.41), and post initiation was -0.25 (95% CI -0.46 to -0.03), with a significant difference in rate of decline (0.33 (95% CI 0.02 to 0.66) (p=0.04)). Most lung function measures were largely unchanged in the year post nusinersen initiation. The total Apnoea-Hypopnoea Index (AHI) was reduced from a median of 5.5 events/hour (IQR 2.1-10.1) at initiation to 2.7 events/hour (IQR 0.7-5.3) after 1 year (p=0.02). All SMA type 1% and 75% of SMA types 2 and 3 had pre-defined peripheral muscle response to nusinersen. CONCLUSION: The first year of nusinersen treatment saw reduced lung function decline (especially in type 2) and improvement in AHI.

Exposure to inorganic particles in paediatric sarcoidosis: the PEDIASARC study.

Inorganic antigens may contribute to paediatric sarcoidosis. Thirty-six patients matched with 36 healthy controls as well as a group of 21 sickle-cell disease (SCD) controls answered an environmental questionnaire. Patients' indirect exposure to inorganic particles, through coresidents' occupations, was higher than in healthy and SCD controls (median score: 2.5 (0.5-7) vs 0.5 (0-2), p=0.003 and 1 (0-2), p=0.012, respectively), especially for construction, exposures to metal dust, talc, abrasive reagents and scouring products. Wood or fossil energies heating were also linked to paediatric sarcoidosis. This study supports a link between mineral environmental exposure due to adult coresident occupations and paediatric sarcoidosis.

Diffuse cystic lung disease in sickle cell anaemia: a series of 22 cases and a case-control study.

Chronic interstitial lung abnormalities have been described in sickle cell disease (SCD) and attributed to repetitive episode of acute chest syndrome. We report a series of 22 cases of diffuse cystic lung disease in SCD with a case-control study to hunt for mechanism. On pathological analysis of a surgical lung biopsy of the index case, the bronchioles had the appearance of constrictive bronchiolitis. Pulmonary function test results revealed lower forced expiratory flow from 25% to 75% of vital capacity in cases versus controls. These findings suggest a bronchiolar mechanism that was not associated with more acute chest syndrome.

Wheeze in the time of COVID-19: overcoming obstacles to an unusual diagnosis.

This case is an example of a rare cause of a common clinical presentation (persistent lobar collapse with wheeze). We describe patient management from primary care through to a national thoracic referral centre. We highlight the importance of objective testing to support an asthma diagnosis and the need to consider alternative or additional diagnoses if a patient does not respond to treatment or the clinical course is unexpected. We highlight the importance of follow-up X-ray to determine whether atelectasis has resolved, which was significantly delayed in this case due to COVID-19 restrictions. Though rare, an endobronchial tumour should be considered if atelectasis persists and when planning endoscopy for a presumed foreign body, especially if the clinical history and patient factors make a foreign body less likely. Greater awareness of this as a differential may expedite diagnoses for patients in future. We show how virtual, multicentre, multidisciplinary meetings can aid rapid diagnosis, surgical planning and coordination of follow-up across centres.

Idiopathic pulmonary fibrosis: Physician and patient perspectives on the pathway to care from symptom recognition to diagnosis and disease burden.

BACKGROUND AND OBJECTIVE: Idiopathic pulmonary fibrosis (IPF) is a chronic progressive disease that requires ongoing care and is associated with considerable socioeconomic burden. We evaluated the IPF care pathway from symptom recognition to treatment. We describe the impact of IPF on healthcare resource use (HCRU), quality of life (QoL) and work impairment, and report differences in patient and physician perspectives using real-world data from France, Germany, Japan and the United States. METHODS: Quantitative, point-in-time data were collected as part of the Adelphi IPF II Disease Specific Programme™. Physician-reported data (patient demographics, medical history, diagnoses, treatment) were matched to patient-reported data (HCRU, QoL, work impairment). HCRU was measured as physician visits and hospitalizations. QoL and work impairment were measured using the EuroQol-5 Dimensions (EQ-5D) and Work Productivity and Activity Impairment questionnaires. RESULTS: Overall, 244 physicians reported data on 1249 patients, 739 of whom self-reported data. Diagnostic delays of 0.8 (Germany) to 2.0 (Japan) years after symptom onset were reported; treatment initiation was further delayed. In all countries, patients more often reported symptoms in the survey than did their physicians. On average, patients underwent 7-10 clinical tests before diagnosis. Antifibrotic use increased from 57% (2016) to 69% (2019); only 50% of patients with moderate/severe IPF were satisfied with their treatment. The 12-month hospitalization rates were 24% (Japan) to 64% (United States). Patients reported low QoL (mean EQ-5D visual analogue scale: 61.7/100). CONCLUSION: Patients with IPF experience considerable diagnostic and treatment delays. More effective therapies and management are needed to reduce the disease burden.

Inhaled nitric oxide improves the hepatopulmonary syndrome: a physiologic analysis.

The hepatopulmonary syndrome (HPS) is defined by liver dysfunction, intrapulmonary vasodilatation and abnormal oxygenation. Hypoxaemia is progressive and liver transplant is the only effective treatment. Severe hypoxaemia is a life-threatening HPS complication, particularly after transplant. We evaluated gas-exchange and haemodynamic effects of invasive therapies in a consecutive sample of 26 pre-transplant patients. Inhaled nitric oxide significantly improved partial pressure of oxygen (12.4 mm Hg; p=0.001) without deleterious effects on cardiac output. Trendelenburg positioning resulted in a small improvement, and methylene blue did not, though individual responses were variable. Future studies should prospectively evaluate these strategies in severe post-transplant hypoxaemia.