Lung clearance index and high-resolution computed tomography scores in primary ciliary dyskinesia

Primary Ciliary Dyskinesia: A Clinical Review

Primary ciliary dyskinesia (PCD) is a rare, genetically heterogeneous, motile ciliopathy, characterized by neonatal respiratory distress, recurrent upper and lower respiratory tract infections, subfertility, and laterality defects. Diagnosis relies on a combination of tests for confirmation, including nasal nitric oxide (nNO) measurements, high-speed videomicroscopy analysis (HSVMA), immunofluorescent staining, axonemal ultrastructure analysis via transmission electron microscopy (TEM), and genetic testing. Notably, there is no single gold standard confirmatory or exclusionary test. Currently, 54 causative genes involved in cilia assembly, structure, and function have been linked to PCD; this rare disease has a spectrum of clinical manifestations and emerging genotype-phenotype relationships. In this review, we provide an overview of the structure and function of motile cilia, the emerging genetics and pathophysiology of this rare disease, as well as clinical features associated with motile ciliopathies, novel diagnostic tools, and updates on genotype-phenotype relationships in PCD.

Magnetic Resonance Imaging of Pulmonary and Paranasal Sinus Abnormalities in Children with Primary Ciliary Dyskinesia Compared to Children with Cystic Fibrosis

Rationale: Primary ciliary dyskinesia (PCD) and cystic fibrosis (CF) are characterized by inherited impaired mucociliary clearance leading to chronic progressive lung disease as well as chronic rhinosinusitis (CRS). The diseases share morphological and functional commonalities on magnetic resonance imaging (MRI) of the lungs and paranasal sinuses, but comparative MRI studies are lacking. Objectives: To determine whether PCD shows different associations of pulmonary and paranasal sinus abnormalities on MRI and lung function test results in children (infants to adolescents) compared with children with CF. Methods: Eighteen children with PCD (median age, 9.5 [IQR, 3.4-12.7] yr; range, 0-18 yr) and 36 age-matched CF transmembrane conductance regulator modulator-naive children with CF (median age, 9.4 [3.4-13.2] yr; range, 0-18 yr) underwent same-session chest and paranasal sinus MRI as well as spirometry (to determine forced expiratory volume in 1 s percent predicted) and multiple-breath washout (to determine lung clearance index z-score). Pulmonary and paranasal sinus abnormalities were assessed using previously validated chest MRI and CRS-MRI scoring systems. Results: Mean chest MRI global score was similar in children with PCD and CF (15.0 [13.5-20.8] vs. 15.0 [9.0-15.0]; P = 0.601). Consolidations were more prevalent and severe in children with PCD (56% vs. 25% and 1.0 [0.0-2.8] vs. 0.0 [0.0-0.3], respectively; P < 0.05). The chest MRI global score correlated moderately with forced expiratory volume in 1 second percent predicted in children with PCD and children with CF (r = -0.523 and -0.687; P < 0.01) and with lung clearance index in children with CF (r = 0.650; P < 0.001) but not in PCD (r = 0.353; P = 0.196). CRS-MRI sum score and mucopyocele subscore were lower in children with PCD than in children with CF (27.5 [26.3-32.0] vs. 37.0 [37.8-40.0] and 2.0 [0.0-2.0] vs. 7.5 [4.8-9.0], respectively; P < 0.01). CRS-MRI sum score did not correlate with chest MRI score in PCD (r = 0.075-0.157; P = 0.557-0.788) but correlated moderately with MRI morphology score in CF (r = 0.437; P < 0.01). Conclusions: MRI detects differences in lung and paranasal sinus abnormalities between children with PCD and those with CF. Lung disease does not correlate with CRS in PCD but correlates in CF.

Comparison of respiratory functions, muscle strength, and physical activity among children with primary ciliary dyskinesia with and without Kartagener's syndrome and healthy controls

INTRODUCTION

Kartagener's syndrome (KS), consisting of bronchiectasis, situs inversus totalis, and sinusitis, is a subtype of primary ciliary dyskinesia (PCD). The presence of KS may affect respiratory and physical functions.

PURPOSE

This study aimed to compare respiratory functions, exercise capacity, muscle strength, and physical activity levels among children with PCD with/without KS and healthy peers.

METHODS

Fifteen patients with KS, 23 with PCD without KS, and 27 controls were compared. Pulmonary function, functional exercise capacity (6-minute walk test - 6MWT), maximal inspiratory, expiratory (MIP, MEP), and skeletal muscle strength, inspiratory muscle endurance (IME), and physical activity level were evaluated.

RESULTS

The forced expiratory volume in one second (FEV1) % (p = .009), forced expiratory flow from 25%-75% (FEF25-75%) % (p = .001), MIP (p = .034), MEP (p = .003), 6MWT distance (p = .001), and daily steps (p = .034) were significantly different among the groups. Quadriceps femoris (QF) muscle strength and IME were similar in groups (p ˃ .05). FEV1% (p = .002), FEF25-75% % (p = .001), MIP (p = .027), MEP (p = .001), and 6MWT distance (p = .003) in patients with KS; 6MWT distance (p = .003) in patients with PCD without KS was significantly lower than controls.

CONCLUSION

The presence of KS affects pulmonary function, respiratory muscle strength, and physical activity more. Exercise capacity and physical activity levels are decreased, inspiratory muscle endurance and QF muscle strength are preserved in patients with KS and PCD without KS. Kartagener's syndrome further impairs pulmonary and extrapulmonary outcomes; the reasons should be investigated, and the necessity of rehabilitation approaches that will prevent deterioration come to the fore.

Primary ciliary dyskinesia

BACKGROUND AND OBJECTIVES

Primary ciliary dyskinesia (PCD, ORPHA:244) is a group of rare genetic disorders characterized by dysfunction of motile cilia. It is phenotypically and genetically heterogeneous, with more than 50 genes involved. Thanks to genetic, clinical, and functional characterization, immense progress has been made in the understanding and diagnosis of PCD. Nevertheless, it is underdiagnosed due to the heterogeneous phenotype and complexity of diagnosis. This review aims to help clinicians navigate this heterogeneous group of diseases. Here, we describe the broad spectrum of phenotypes associated with PCD and address pitfalls and difficult-to-interpret findings to avoid misinterpretation.

METHOD

Review of literature CONCLUSION: PCD diagnosis is complex and requires integration of history, clinical picture, imaging, functional and structural analysis of motile cilia and, if available, genetic analysis to make a definitive diagnosis. It is critical that we continue to expand our knowledge of this group of rare disorders to improve the identification of PCD patients and to develop evidence-based therapeutic approaches.

Lung Function in Children with Primary Ciliary Dyskinesia

BACKGROUND

Primary ciliary dyskinesia (PCD) is characterized by impaired mucociliary clearance that results in accumulation of mucus and bacteria in the airways. Lower respiratory tract infections lead to airway remodeling and lung function impairment. The aim of our narrative review is to discuss available data on lung function in PCD children, focusing on risk factors for lung function impairment.

METHODS

Relevant published studies searching MEDLINE/Pubmed are included in this narrative review, using these terms: "primary ciliary dyskinesia" and "pulmonary function test" or "spirometry" or "lung function". Filters were language (English) and age of study subjects (0-18 years).

RESULTS AND CONCLUSIONS

The majority of recent published studies showed normal spirometric values in PCD children, even if some authors described a pulmonary impairment. Together with spirometry, Lung Clearance Index has been applied for detecting peripheral airway disease, and it might have a role in early mild lung disease assessment. Studies on lung function trajectories after PCD diagnosis showed a significant heterogeneity, with some patients maintaining reasonably good lung function, whereas others showing a decline. Further studies are needed to analyze lung function prospectively from childhood into adulthood, and to evaluate whether lung function trajectories are affected by PCD clinical phenotype, ultrastructural ciliary defect or genetic background.

In children with primary ciliary dyskinesia, which type of lung function test is the earliest determinant of decline in lung health: A systematic review

BACKGROUND

Primary ciliary dyskinesia is a rare genetic disorder characterized by recurrent sinopulmonary infections and worsening obstructive lung disease. Kidney and brain involvement is less common and is associated with overlapping ciliopathies/syndromes. The lungs are impacted early in the course of the disease, so it is vital to monitor lung function and recognize any decline by doing appropriate lung function tests. This systematic review compares different lung function tests and analyzes which one becomes abnormal earlier in the disease.

METHODS

A systematic review was conducted following the methodology in the "Cochrane Handbook on Systematic Reviews for diagnostic tests." The Preferred Reporting Items for Systematic Review and Meta-Analyses were used to report the results. The risk of bias assessment was done using "The Cochrane Handbook for Systematic Reviews tool for interventional studies." A meta-analysis was not performed due to the small sample size. All studies were analyzed by using Joanna Briggs Institute's critical appraisal tool.

RESULTS

After screening for the duplication of results and applying inclusion and exclusion criteria, 14 studies were assessed by reading the full texts. Out of these, eight were finally included in this systematic review. The total sample size from all studies was 165, including 80 males. All the studies used spirometry as a lung function test, whereas multiple breath washout was used in five studies. Other tests used for comparison were computed tomography (CT), magnetic resonance imaging (MRI), cardiopulmonary exercise testing, 6-min walk test, DLCO, maximal inspiratory pressure, maximal expiratory pressure, and PaO₂ . Lung clearance index (LCI) by multiple breath washout had a stronger association with the structural changes on CT/MRI than spirometry indices like forced expiratory volume in 1 s (FEV1) and forced expiratory flow at 25% to 75% of lung volume (FEF 25-75).

CONCLUSIONS

Based on the evidence from this systematic review, LCI becomes abnormal earlier than FEV1 or FEF 25-75 and positively correlates with the findings on high-resolution CT. It has limitations like the lack of reference values and a complex technique to perform the test.

Curvilinearity provides additional information to lung clearance index only in a minority of children with early cystic fibrosis lung disease

Advances in technology and international consensus guidelines [1] make multiple breath washout (MBW) testing feasible in many settings, particularly in cystic fibrosis (CF) centres, and in paediatrics, as many children and young people with respiratory disease may have normal spirometry [2].

Curvilinearity, as calculated from multiple-breath washout, is abnormal in a small number of children with cystic fibrosis when other tests are still normalhttps://bit.ly/3p9QAV4

Chronic airway disease in primary ciliary dyskinesia—spiced with geno–phenotype associations

Primary ciliary dyskinesia (PCD) can be defined as a multiorgan ciliopathy with a dominant element of chronic airway disease affecting the nose, sinuses, middle ear, and in particular, the lower airways. Although most patients with PCD are diagnosed during preschool years, it is obvious that the chronic lung disease starts its course already from birth. The many faces of the clinical picture change, as does lung function, structural lung damage, the burden of infection, and of treatment throughout life. A markedly severe neutrophil inflammation in the respiratory tract seems pervasive and is only to a minimal extent ameliorated by a treatment strategy, which is predominantly aimed at bacterial infections. An ever‐increasing understanding of the different aspects, their interrelationships, and possible different age courses conditioned by the underlying genotype is the focus of much attention. The future is likely to offer personalized medicine in the form of mRNA therapy, but to that end, it is of utmost importance that all patients with PCD be carefully characterized and given a genetic diagnosis. In this narrative review, we have concentrated on lower airways and summarized the current understanding of the chronic airway disease in this motile ciliopathy. In addition, we highlight the challenges, gaps, and opportunities in PCD lung disease research.

Lower airway clinical outcome measures for use in primary ciliary dyskinesia research: a scoping review

Objectives

Disease-specific, well-defined and validated clinical outcome measures are essential in designing research studies. Poorly defined outcome measures hamper pooling of data and comparisons between studies. We aimed to identify and describe pulmonary outcome measures that could be used for follow-up of patients with primary ciliary dyskinesia (PCD).

Methods

We conducted a scoping review by systematically searching MEDLINE, Embase and the Cochrane Database of Systematic Reviews online databases for studies published from 1996 to 2020 that included ≥10 PCD adult and/or paediatric patients.

Results

We included 102 studies (7289 patients). 83 studies reported on spirometry, 11 on body plethysmography, 15 on multiple-breath washout, 36 on high-resolution computed tomography (HRCT), 57 on microbiology and 17 on health-related quality of life. Measurement and reporting of outcomes varied considerably between studies (e.g. different scoring systems for chest HRCT scans). Additionally, definitions of outcome measures varied (e.g. definition of chronic colonisation by respiratory pathogen), impeding direct comparisons of results.

Conclusions

This review highlights the need for standardisation of measurements and reporting of outcome measures to enable comparisons between studies. Defining a core set of clinical outcome measures is necessary to ensure reproducibility of results and for use in future trials and prospective cohorts.

Comparison of Multiple Breath Washout and Spirometry in Children with Primary Ciliary Dyskinesia and Cystic Fibrosis and Healthy Controls

Rationale: In cystic fibrosis (CF), the lung clearance index (LCI), derived from multiple breath washout (MBW), is more sensitive in detecting early lung disease than FEV₁; MBW has been less thoroughly evaluated in young patients with primary ciliary dyskinesia (PCD).Objectives: Our objectives were 1) to evaluate the sensitivity of MBW and spirometry for the detection of mild lung disease in young children with PCD and CF compared with healthy control (HC) subjects and 2) to compare patterns of airway obstruction between disease populations.Methods: We used a multicenter, single-visit, observational study in children with PCD and CF with a forced expiratory volume in 1 second (FEV₁) greater than 60% predicted and HC subjects, ages 3-12 years. Nitrogen MBW and spirometry were performed and overread for acceptability. χ² and Kruskall-Wallis tests compared demographics and lung function measures between groups, linear regression evaluated the effect of disease state, and Spearman's rank correlation coefficient compared the LCI and spirometric measurements.Results: Twenty-five children with PCD, 49 children with CF, and 80 HC children were enrolled, among whom 17 children with PCD (68%), 36 children with CF (73%), and 53 (66%) HC children performed both acceptable spirometry and MBW; these children made up the analytic cohort. The median age was 9.0 years (interquartile range [IQR], 6.8-11.1). The LCI was abnormal (more than 7.8) in 10 of 17 (59%) patients with PCD and 21 of 36 (58%) patients with CF, whereas FEV₁ was abnormal in three of 17 (18%) patients with PCD and six of 36 (17%) patients with CF. The LCI was significantly elevated in patients with PCD and CF compared with HC subjects (ratio of geometric mean vs. HC: PCD 1.27; 95% confidence interval [CI], 1.15-1.39; and CF 1.24; 95% CI, 1.15-1.33]). Children with PCD had lower midexpiratory-phase forced expiratory flow % predicted compared with children with CF (62% [IQR, 50-78%] vs. 85% [IQR, 68-99%]; P = 0.05). LCI did not correlate with FEV₁.Conclusions: The LCI is more sensitive than FEV₁ in detecting lung disease in young patients with PCD, similar to CF. LCI holds promise as a sensitive endpoint for the assessment of early PCD lung disease.

Multiple breath washout: A noninvasive tool for identifying lung disease in symptomatic military deployers

RATIONALE

Military deployments to austere environments since November 9, 2001 may put "deployers" at risk for respiratory disease. Sensitive, noninvasive tools for detecting large and small airways injury are needed to identify early disease and help inform management for this at-risk population.

OBJECTIVES

We examined multiple breath washout (MBW) as a tool for identifying deployment-related airways disease and assessed host and exposure risk factors compared to healthy controls.

METHODS

Between March 2015 and March 2020, 103 healthy controls and 71 symptomatic deployers with asthma and/or distal lung disease completed a questionnaire, spirometry and MBW testing. SAS v. 9.4 was used to compare MBW parameters between deployers and controls via univariate analyses and adjusted for demographic factors using multiple linear regression.

MEASUREMENTS AND MAIN RESULTS

Deployers were significantly more likely than controls to have an abnormal lung clearance index (LCI) score indicating global ventilation inhomogeneity. Adjusting for sex, smoking status, smoking pack-years and body mass index, LCI scores were significantly more abnormal among those with deployment-related asthma and distal lung disease compared to controls. The unadjusted variable Sacin (a marker of ventilation inhomogeneity in the acinar airways) was higher and thus more abnormal in those with both proximal and distal airways disease. Deployers who reported more frequent exposure to explosive blasts had significantly higher LCI scores.

CONCLUSIONS

This study demonstrates the utility of MBW in evaluating exposure-related airways disease in symptomatic military personnel following deployment to austere environments, and is the first to link exposure to explosive blasts to measurable small airways injury.

Do pulmonary and extrapulmonary features differ among cystic fibrosis, primary ciliary dyskinesia, and healthy children?

BACKGROUND

Primary ciliary dyskinesia (PCD) is generally likened to cystic fibrosis (CF) due to similarities in impaired mucociliary clearance and some other symptoms. The aim of our study was to investigate pulmonary and extrapulmonary characteristics of children with CF and PCD since no studies have addressed respiratory muscle strength in children with PCD and to compare the results to those obtained from healthy age-matched controls.

METHODS

Pulmonary and extrapulmonary characteristics were assessed by 6-min walk test, spirometry, maximum inspiratory and expiratory pressure measurements, and knee extensor strength test in the children with CF, PCD, and healthy controls.

RESULTS

Children with PCD and CF had similar PFT results, except forced expiratory flow between 25% and 75% of vital capacity (FEF_25-75 ) which was lower in PCD (p = .04). Maximum inspiratory pressure (MIP) value was lower in the children with CF compared with the healthy controls (p = .016), MEP value of the children with PCD was worse than those with CF and healthy controls (p = .013 and p = .013), respectively. 6-min walk test (6MWT) distance of the children with CF was lower than their healthy counterparts (p = .003). Knee extensor muscle strength differed among the children with PCD, CF, and healthy control groups, but post hoc test failed to show statistical significance (p = .010).

CONCLUSION

Children with CF and PCD had some impairments in pulmonary functions, respiratory muscle strength, functional capacity, and peripheral muscle strength compared with healthy children. However, the unique characteristics of each disease should be considered during physiotherapy assessment and treatment. The clinicians may especially focus on the respiratory and peripheral muscle strength of the children with PCD.

[Management of Primary Ciliary Dyskinesia]

Die Primäre Ciliäre Dyskinesie (PCD, MIM 242650) ist eine seltene hereditäre Multisystemerkrankung mit klinisch heterogenem Phänotyp. Leitsymptom ist eine chronische Sekretretention der oberen und unteren Atemwege, welche durch die Dysfunktion motiler respiratorischer Zilien entsteht. In der Folge kommt es zur Ausbildung von Bronchiektasen, häufig zu einer Infektion durch Pseudomonas aeruginosa sowie einer abnehmenden Lungenfunktion bis hin zum Lungenversagen.

Bislang gibt es kaum evidenzbasierte Therapieempfehlungen, da randomisierte Langzeitstudien zur Behandlung der PCD fehlten. In diesem Jahr wurden die Daten einer ersten placebokontrollierten Medikamentenstudie bei PCD veröffentlicht. Anlässlich dieses Meilensteins im Management der PCD wurde der vorliegende Übersichtsartikel als Konsens von Patientenvertretern sowie Klinikern, die langjährige Erfahrung in der Behandlung der PCD haben, verfasst. Diese Arbeit bietet eine Zusammenfassung aktuell eingesetzter Behandlungsverfahren, die überwiegend auf persönlichen Erfahrungen und Expertenmeinungen beruhen oder von anderen Atemwegserkrankungen wie der Cystischen Fibrose (CF), COPD oder Bronchiektasen-Erkrankung abgeleitet werden. Da es derzeit keine kurative Therapie für PCD gibt, stehen symptomatische Maßnahmen wie die regelmäßige Reinigung der Atemwege und die Behandlung von rezidivierenden Atemwegsinfektionen im Fokus. Nicht respiratorische Manifestationen werden organspezifisch behandelt. Um neben der ersten Medikamentenstudie mehr evidenzbasiertes Wissen zu generieren, werden weitere Projekte etabliert, u. a. ein internationales PCD-Register. Hierüber wird Patienten der Zugang zu klinischen und wissenschaftlichen Studien erleichtert und die Vernetzung behandelnder Zentren gefördert. Des Weiteren können Erkenntnisse über eine Genotyp-spezifische Erkrankungsschwere erlangt werden, um folglich die therapeutische Versorgung der Patienten zu verbessern und somit zu individualisieren.

Non-cystic fibrosis bronchiectasis in children and adolescents: Neglected and emerging issues

Pediatric non-cystic fibrosis (CF) bronchiectasis is characterized by endobronchial suppuration, airway neutrophilic inflammation and poor mucus clearance and is associated with persistent productive cough due to recurrent airway infections. Most recommendations are based on expert opinion or extrapolated from CF practice. The present narrative review aims to address some issues on the management of children or adolescents with non CF-bronchiectasis that still require attention, and analyze what available literature offers to reply to open questions. We focused on the potential offered by technological advances on lung disease assessment through novel chest imaging techniques and new or old pulmonary function tests. We also summarized the main novelties in the disease prevention and treatment. Finally, a novel diagnostic algorithm is proposed, that might help physicians in the daily clinical decision-making process. Future directions for research on pediatric non-CF bronchiectasis should include larger study populations and longer prospective clinical trials, as well as new clinical and laboratory endpoints to determine the underlying mechanisms of lung disease progression and support the role of new and existing treatments.

Health related quality of life in adult primary Ciliary dyskinesia patients in Cyprus: development and validation of the Greek version of the QOL-PCD questionnaire

BACKGROUND

The QOL-PCD questionnaire is a recently developed Health Related Quality of Life (HRQoL) instrument for Primary Ciliary Dyskinesia. The aim of this study was to translate the adult QOL-PCD questionnaire into Greek language and to conduct psychometric validation to assess its performance.

METHODS

Forward translations to Greek and backward translation to English were performed, followed by cognitive interviews in 12 adult PCD patients. The finalized translated version was administered to a consecutive sample of 31 adult, Greek speaking PCD patients in Cyprus for psychometric validation, which included assessment of internal consistency, test-retest reliability, construct and convergent validity. Internal consistency was assessed by Cronbach's alpha test in terms of the overall and sub-scales. Test-retest reliability was assessed by repeat administration of the questionnaire within 2 weeks and calculation of the intra-class correlation (ICC). Construct validity was assessed by comparing different groups of patients based on a-priori hypotheses and convergent validity was evaluated by examining associations between the QOL-PCD and SF-36 questionnaires.

RESULTS

Moderate to good internal consistency was observed (Cronbach's α: 0.46-0.88 across sub-scales) and test-retest reliability assessment demonstrated good repeatability for most scales (ICC: 0.67-0.91 across subscales). Patients of female gender, older age and lower lung function exhibited lower QOL-PCD scores in general, while high correlations for most QOL-PCD scales with corresponding SF-36 scales were observed, in particular for physical functioning (r = 0.78, p < 0.05).

CONCLUSION

The adult version of QoL-PCD questionnaire has been translated according to international guidelines resulting to a cross-culturally validated Greek version which exhibited moderate to good metric properties in terms of internal consistency, stability, known-group and convergent validity.

Lung clearance index and steroid response in pediatric severe asthma

INTRODUCTION

Lung clearance index (LCI) is a measure of airway disease that has been shown to be abnormal in asthma. We hypothesized that LCI would be higher (worse) in children with severe therapy-resistant asthma (STRA) compared with difficult asthma (DA) and healthy controls and that LCI would fall in response to parenteral steroids in STRA.

METHODS

Sixty-four children with asthma who were prescribed high-dose asthma therapy (GINA steps 4 or 5) performed LCI and spirometry. Forty-three had STRA and 21 DA. Thirty-nine of forty-three STRA patients attended for a clinically indicated bronchoscopy during which an intramuscular injection of triamcinolone was given. LCI, spirometry, and fractional exhaled nitric oxide (FeNO) were performed on the day of the bronchoscopy and repeated 4 weeks later.

RESULTS

LCI was more abnormal in STRA (median: 7.40, range: 5.58-12.34) than in DA (6.55, 5.77-7.75), P = .0006, and healthy controls (6.53, 5.57-7.35), P = .005. In contrast to the first second forced expired volume (FEV₁ ), LCI improved following systemic steroids; of 20 STRA patients with an abnormal LCI at baseline, 13 improved following triamcinolone. LCI and FeNO responses were concordant.

CONCLUSIONS

There is a subgroup of children with STRA in whom LCI is elevated who improve following parenteral steroids. LCI may be a valuable additional domain in assessing steroid response in pediatric asthma.

Validation of pediatric health-related quality of life instruments for primary ciliary dyskinesia (QOL-PCD)

RATIONALE

Having developed the first disease-specific, health-related quality of life (HRQoL) instruments for children with primary ciliary dyskinesia (PCD), we aimed to assess the psychometric performance of quality of life (QOL)-PCD child, adolescent, and parent-proxy versions in terms of reliability and validity across cross-cultural settings and caring for patients with this rare disease.

METHODS

Children (n = 71), adolescents (n = 85), and parents (n = 68) from multiple centers in the UK and North America completed age-appropriate QOL-PCD and generic QOL measures: pediatric QOL inventory, COPD assessment test (CAT), and Sino-Nasal Outcome Test 20. Total of 13 children, 13 parents, and 17 adolescents repeated QOL-PCD 10 to 14 days later to assess test-retest reliability. Multitrait analysis evaluated how the items loaded to hypothesized scales: physical, emotional & social functioning, treatment burden, role, vitality, upper and lower respiratory symptoms, and ears and hearing symptoms. Examination of item-to-total correlations led to removal of three, five, and six items, respectively in the prototype child, adolescent and parent-proxy versions; the validated measures now comprise between 34 and 38 items.

RESULTS

The QOL-PCD scales had good internal consistency; Cronbach's α for QOL-PCD parent-proxy ranged 0.62 to 0.86. Test-retest reliability demonstrated stability across all scales; for example QOL-PCD adolescent intraclass correlation coefficients ranged 0.71 to 0.89. Significant relationships were found between QOL-PCD scales and similar constructs on generic questionnaires, for example, QOL-PCD adolescent lower respiratory symptoms and the CAT score (r = .64, P < .01); weaker correlations were found between different constructs.

CONCLUSION

Age-specific QOL-PCD demonstrated good internal consistency, test-retest reliability, and validity. QOL-PCD offers promising outcome measures for multicenter clinical trials, as well as monitoring symptoms, functioning, and QOL during routine care.

Ventilation Inhomogeneity and Bronchial Basement Membrane Changes in Chronic Neutrophilic Airway Inflammation

BACKGROUND

Bronchial epithelial reticular basement membrane (RBM) thickening occurs in diseases with both eosinophilic (allergic bronchial asthma [BA]) and neutrophilic (cystic fibrosis [CF] and primary ciliary dyskinesia [PCD]) chronic airway inflammation; however, the lung function and airway remodeling relation remains unclear. The aim of this study was to test whether ventilation inhomogeneity is related to RBM thickening.

METHODS

Multiple breath washout test, endobronchial biopsy, and BAL were performed in 24 children with CF, 11 with PCD, 15 with BA, and in 19 control subjects. Lung clearance index at 2.5% (1/40th) of starting nitrogen concentration (LCI_2.5), RBM thickness, and lavage fluid cytology were quantified; their mutual associations were studied by using Spearman rank correlations (r).

RESULTS

In asthma, ventilation inhomogeneity (mean ± SD) was mild (LCI_2.5, 9.3 ± 1.4 vs 7.9 ± 0.9 in control subjects; P = .0391), and the RBM thickened (5.26 ± 0.98 μm vs 3.12 ± 0.62 μm in control subjects; P < .0001). No relation between RBM thickness and ventilation inhomogeneity or lavage cytology was found. In CF and PCD, RBM thickness was similar to that in asthma (4.54 ± 0.66 μm and 5.27 ± 1.11 μm, respectively), but ventilation inhomogeneity was significantly higher (LCI_2.5, 12.5 ± 2.4 and 11.8 ± 2.5). Both in CF and PCD, RBM thickness correlated with LCI_2.5 (r = 0.594, P = .015; r = 0.821, P = .023). In PCD only, RBM thickness was also related to the number of neutrophils in lavage fluid (r = 0.821; P = .023).

CONCLUSIONS

Lung function impairment in relation to RBM thickness was milder in BA than in CF and PCD. In asthma, ventilation inhomogeneity did not correlate with RBM thickness, whereas it did in CF and PCD. This outcome suggests a different structure-function relation in these diseases.

Primary ciliary dyskinesia in the genomics age

Primary ciliary dyskinesia is a genetically and clinically heterogeneous syndrome. Impaired function of motile cilia causes failure of mucociliary clearance. Patients typically present with neonatal respiratory distress of unknown cause and then continue to have a daily wet cough, recurrent chest infections, perennial rhinosinusitis, otitis media with effusion, and bronchiectasis. Approximately 50% of patients have situs inversus, and infertility is common. While understanding of the underlying genetics and disease mechanisms have substantially advanced in recent years, there remains a paucity of evidence for treatment. Next-generation sequencing has increased gene discovery, and mutations in more than 40 genes have been reported to cause primary ciliary dyskinesia, with many other genes likely to be discovered. Increased knowledge of cilia genes is challenging perceptions of the clinical phenotype, as some genes reported in the last 5 years are associated with mild respiratory disease. Developments in genomics and molecular medicine are rapidly improving diagnosis, and a genetic cause can be identified in approximately 70% of patients known to have primary ciliary dyskinesia. Groups are now investigating novel and personalised treatments, although gene therapies are unlikely to be available in the near future.

Spirometric indices in primary ciliary dyskinesia: systematic review and meta-analysis

Primary ciliary dyskinesia (PCD) is a genetic, heterogeneous disease caused by dysfunction of cilia. Evidence is sparse and reports of lung function in PCD patients range from normal to severe impairment. This systematic review and meta-analysis of studies of lung function in PCD patients examines the spirometric indices of PCD patients and differences by age group and sex.

We searched PubMed, Embase and Scopus for studies that described lung function in 10 or more patients with PCD. We performed meta-analyses and meta-regression to explain heterogeneity. We included 24 studies, ranging from 13 to 158 patients per study.

The most commonly reported spirometric indices were forced expiratory volume in 1 s (FEV₁) and forced vital capacity presented as mean and standard deviation of percent predicted values. We found considerable heterogeneity for both parameters (I²=94–96%). The heterogeneity remained when we stratified the analysis by age; however, FEV₁ in adult patients was lower. Even after taking into account explanatory factors, the largest part of the between-studies variance remained unexplained.

Heterogeneity could be explained by genetic differences between study populations, methodological factors related to the variability of study inclusion criteria or details on the performance and evaluation of lung function measurements that we could not account for. Prospective studies therefore need to use standardised protocols and international reference values. These results underline the possibility of distinct PCD phenotypes as in other chronic respiratory diseases. Detailed characterisation of these phenotypes and related genotypes is needed in order to better understand the natural history of PCD.

Spirometric indices of PCD patients vary between published studies, which suggests not only the possibility of methodological differences between centres but also real differences in disease expression based on genotype–phenotype associationshttp://ow.ly/wopw30nYaJo

CF derived scoring systems do not fully describe the range of structural changes seen on CT scans in PCD

BACKGROUND

Structural lung changes seen on computed tomography (CT) scans in Cystic Fibrosis (CF) and Primary Ciliary Dyskinesia (PCD) are currently described using scoring systems derived from CF populations. This practise assumes lung damage in the two conditions is identical, potentially resulting in a failure to identify PCD-specific changes. Our study addresses this assumption.

METHODS

A total of 58 CT scans from 41 PCD patients (age 2-48 years) were examined and the presence and extent of abnormalities common in CF; bronchiectasis, bronchial wall thickening, atelectasis, mucous plugging, and air trapping noted. Further assessment of the PCD scans by an experienced chest radiologist identified several unique PCD specific changes.

RESULTS

Bronchial wall thickening was the commonest abnormality seen in PCD. All abnormalities were present more often in middle and lower lobes than in upper lobes (P < 0.001). Bronchiectasis, mucus plugging, atelectasis, and air trapping were present more often in PCD than in the historic CF cohorts which formed the basis of two CF scoring systems (P < 0.05). Extensive tree-in-bud pattern of mucus plugging, thickening of interlobar, and interlobular septa, and whole lobe atelectasis were seen significantly more frequently in PCD than CF.

CONCLUSIONS

Structural changes identified on CT scans in PCD are not identical to those previously described in CF patients and suggest assessment of PCD structural changes on CT should not use CF derived scoring systems.

One-year evolution and variability in multiple-breath washout indices in children and young adults with primary ciliary dyskinesia

Background and objective: Cross-sectional and longer-term studies have demonstrated abnormal yet stable multiple-breath inert gas washout (MBW) indices in patients with primary ciliary dyskinesia (PCD). This study aimed to assess the intermediate term evolution and the between-occasion variability of MBW indices in PCD over 1 year.

Methods: Children and young adults with a confirmed diagnosis of PCD were included in this single-centre, prospective, observational, longitudinal study. Over 1 year, nitrogen (N₂) MBW and spirometry were performed at three occasions during ordinary scheduled outpatient visits. Trends and variability in lung clearance index (LCI), moment ratios, normalized N₂ concentration at six lung volume turnovers, and regional ventilation inhomogeneity indices of the conducting and intra-acinar airways (S_cond*V_T and S_acin*V_T) were analysed using linear mixed models.

Results: Forty-two patients, aged 6–29 years (median: 15.4), performed 116 N₂ MBW test occasions and 96.6% were technically acceptable. A minimal, although significant, increase in LCI over 1 year (mean: 0.51 units, 95% CI: 0.12–0.91, p = 0.01) was found; while, all other N₂ MBW indices and FEV₁ remained unchanged. A moderate correlation was observed between LCI and FEV₁ (r = −0.47, p = 0.0001). The limits of agreement between tests 1 year apart were for LCI: −1.96 to 2.98; S_cond*V_T: ± 0.039; S_acin*V_T: −0.108 to 0.128.

Conclusions: Children and young adults with PCD managed at a specialist centre showed slightly, but significant, increasing LCI and otherwise unchanged ventilation inhomogeneity indices and dynamic volumes over the intermediate term of 1 year. Estimates of the variability of N₂ MBW indices may inform sample size calculations of future randomized controlled trials.

Bronchiectasis: a case-based approach to investigation and management

Bronchiectasis is a chronic respiratory disease characterised by a syndrome of productive cough and recurrent respiratory infections due to permanent dilatation of the bronchi. Bronchiectasis represents the final common pathway of different disorders, some of which may require specific treatment. Therefore, promptly identifying the aetiology of bronchiectasis is recommended by the European Respiratory Society guidelines. The clinical history and high-resolution computed tomography (HRCT) features can be useful to detect the underlying causes. Despite a strong focus on this aspect of treatment a high proportion of patients remain classified as "idiopathic". Important underlying conditions that are treatable are frequently not identified for prolonged periods of time.The European Respiratory Society guidelines for bronchiectasis recommend a minimal bundle of tests for diagnosing the cause of bronchiectasis, consisting of immunoglobulins, testing for allergic bronchopulmonary aspergillosis and full blood count. Other testing is recommended to be conducted based on the clinical history, radiological features and severity of disease. Therefore it is essential to teach clinicians how to recognise the "clinical phenotypes" of bronchiectasis that require specific testing.This article will present the initial investigation and management of bronchiectasis focussing particularly on the HRCT features and clinical features that allow recognition of specific causes.

Gas exchanges in children with cystic fibrosis or primary ciliary dyskinesia: A retrospective study

Primary ciliary dyskinesia (PCD) and cystic fibrosis (CF) both entail bronchiectasis and pulmonary impairment as measured using spirometry, during childhood. We aimed at looking whether blood gas exchanges progressed differently between CF and PCD children in a retrospective study of repeated measurements. Comparisons between groups (Wilcoxon-Mann-Whitney and Chi-squared tests) and a mixed linear model, adjusted for age, evaluated associations between diseases and PaO₂, PaCO_2, or PaO_2-PaCO₂ ratio. Among 42 PCD and 73 CF children, 62% and 59% had respectively bronchiectasis (P = 0.75). Spirometry and blood gases were similar at inclusion (PaO₂ median [IQR] PCD -1.80 [-3.40; -0.40]; CF -1.80 [-4.20; 0.60] z-scores; P = 0.72). PaO₂ and PaO₂-PaCO₂ ratio similarly and significantly decreased with age in both groups (P < 0.01) whereas PaCO₂ increased more in CF (P = 0.02) remaining within the range of normal (except for one child). To conclude, gas exchange characteristics, similarly initially impaired in PCD and CF children, tended to less deteriorate with time in PCD children who could benefit from an early diagnosis.

Primary Ciliary Dyskinesia Due to Microtubular Defects is Associated with Worse Lung Clearance Index

Purpose

Primary ciliary dyskinesia (PCD) is characterised by repeated upper and lower respiratory tract infections, neutrophilic airway inflammation and obstructive airway disease. Different ultrastructural ciliary defects may affect lung function decline to different degrees. Lung clearance index (LCI) is a marker of ventilation inhomogeneity that is raised in some but not all patients with PCD. We hypothesised that PCD patients with microtubular defects would have worse (higher) LCI than other PCD patients.

Methods

Spirometry and LCI were measured in 69 stable patients with PCD. Age at testing, age at diagnosis, ethnicity, ciliary ultrastructure, genetic screening result and any growth of Pseudomonas aeruginosa was recorded.

Results

Lung clearance index was more abnormal in PCD patients with microtubular defects (median 10.24) than those with dynein arm defects (median 8.3, p = 0.004) or normal ultrastructure (median 7.63, p = 0.0004). Age is correlated with LCI, with older patients having worse LCI values (p = 0.03, r = 0.3).

Conclusion

This study shows that cilia microtubular defects are associated with worse LCI in PCD than dynein arm defects or normal ultrastructure. The patient’s age at testing is also associated with a higher LCI. Patients at greater risk of obstructive lung disease should be considered for more aggressive management. Differences between patient groups may potentially open avenues for novel treatments.

Electronic supplementary material

The online version of this article (10.1007/s00408-018-0086-x) contains supplementary material, which is available to authorized users.

[Silent lung zone - application of multi-breath nitrogen washout test (MBNW) in the diagnosis of small airways diseases in children - preliminary report based on literature and own experience]

Small airways are the site of pathological changes often in an early stage in many diseases such as asthma or cystic fibrosis. However this part of the airways is overlooked in conventional respiratory function tests and it is therefore often referred to as "silent lung zone". This paper presents the theoretical background of MBNW multi-breath nitrogen washout in the diagnosis of minor respiratory diseases. The technical issues related to the preparation of pediatric patients for the test. Clinical applications of the MBNW test results are still subject to a number of studies. There is hope for filling the gaps in the small airway function tests. Due to the authors' involvement in the diagnosis and treatment of patients with cystic fibrosis, their own experience in the use of this study was also described. Currently, the method is in the phase of intensive analysis for the early diagnosis of lung disease in cystic fibrosis, when still other functional tests are in normal range or impossible to perform due to patient age. Correlation with medical imaging methods (chest computed tomography) and the severity of structural changes may in future limit the amount of radiology tests. In addition this can reduce the patient's exposure to ionizing radiation. Introduction of lung function tests such a MBW in infants and preschool children with cystic fibrosis and other minor respiratory diseases may modify clinical management and improve prognosis.

Airway Clearance Techniques for Primary Ciliary Dyskinesia; is the Cystic Fibrosis literature portable?

Primary Ciliary Dyskinesia (PCD) is a rare inherited disease with impaired mucociliary clearance. Airway clearance techniques (ACTs) are commonly recommended for patients with PCD to facilitate mucus clearance, despite a lack of evidence in this group. Current physiotherapy practice in PCD is based on evidence extrapolated from the field of Cystic Fibrosis (CF). This paper focuses on the available evidence and outlines challenges in extrapolating evidence between the conditions for best clinical practice.

Primary Ciliary Dyskinesia: First Health-related Quality-of-Life Measures for Pediatric Patients

RATIONALE

Primary ciliary dyskinesia (PCD) is a rare disease. There are no available data on disease-specific pediatric patient-reported outcomes.

OBJECTIVES

Our objective was to create developmentally appropriate, health-related quality-of-life questionnaires (QOL-PCD) for children (6-12 yr) and adolescents (13-17 yr) with PCD and a parent proxy measure.

METHODS

The QOL-PCD was developed using a cross-cultural protocol-driven approach satisfying both North American and European drug regulatory agency guidelines. A conceptual framework was generated by literature review, focus groups (expert clinicians and patients/parents), and open-ended interviews with children, adolescents, and parents of patients with PCD. We recruited participants from international research consortiums, PCD clinics, and patient advocacy groups, aiming for representation of a wide spectrum of disease severity, sociodemographic status, and ethnicity. Qualitative interviews were conducted by trained and experienced research assistants and psychologists. Transcripts were content-analyzed with Atlas.ti/NVivo to assess saturation of content. A self-completed item relevance survey was administered to E.U.

PARTICIPANTS

Qualitative and quantitative data were used to construct draft instruments. Questionnaires were further refined after cognitive interviews.

MEASUREMENTS AND MAIN RESULTS

Focus groups (n = 62 experts; n = 20 patients/parents) and open-ended interviews with patients/parents (n = 69; 34 males; age at diagnosis, 0-15 yr; FEV₁, 58-118% predicted) revealed a wide spectrum of issues unique to this population. Content analysis of transcripts identified the following domains, depending on age: Respiratory Symptoms, Physical Functioning, Emotional Functioning, Treatment Burden, Ears and Hearing, Sinus Symptoms, Social Functioning, Role Functioning, Vitality, Health Perceptions, School Functioning, and Eating and Weight. Various items were retained in questionnaires, based on age and role of respondent: 37, 43, and 41 items for children, adolescents, and parent proxy, respectively. The item relevance survey (n = 57) yielded results similar to those of open-ended interviews. Cognitive testing (n = 47; 20 males; age at diagnosis, 0-11 yr; FEV₁, 49-124% predicted) confirmed that items and response choices were clear and understood by respondents, and that all relevant items were included.

CONCLUSIONS

The QOL-PCD measures, developed using rigorous, protocol-driven methods and international collaborations, have demonstrated content validity and cross-cultural equivalence for implementation in English-speaking populations. Psychometric testing is underway to determine their measurement properties for evaluating clinical interventions and informing quality of care.

Clinical care for primary ciliary dyskinesia: current challenges and future directions

Primary ciliary dyskinesia (PCD) is a rare genetic disease that affects the motility of cilia, leading to impaired mucociliary clearance. It is estimated that the vast majority of patients with PCD have not been diagnosed as such, providing a major obstacle to delivering appropriate care. Challenges in diagnosing PCD include lack of disease-specific symptoms and absence of a single, "gold standard", diagnostic test. Management of patients is currently not based on high-level evidence because research findings are mostly derived from small observational studies with limited follow-up period. In this review, we provide a critical overview of the available literature on clinical care for PCD patients, including recent advances. We identify barriers to PCD research and make suggestions for overcoming challenges.

Residual volume/total lung capacity ratio confers limited additive significance to lung clearance index for assessment of adults with bronchiectasis

BACKGROUND

Mosaicism and hyperinflation are common pathophysiologic features of bronchiectasis. The magnitude of ventilation heterogeneity might have been affected by the degree of hyperinflation. Some studies have evaluated the discriminative performance of lung clearance index (LCI) in bronchiectasis patients, but the additive diagnostic value of hyperinflation metrics to LCI is unknown.

OBJECTIVE

To compare LCI and the ratio of residual volume to total lung capacity (RV/TLC), along with the LCI normalized with RV/TLC, in terms of discriminative performance, correlation and concordance with clinical variables in adults with bronchiectasis.

METHODS

Measurement items included chest high-resolution computed tomography, multiple-breath nitrogen washout test, spirometry, and sputum culture. We analyzed bronchodilator responses by stratifying LCI and RV/TLC according to their median levels (LCIHigh/RV/TLCHigh, LCILow/RV/TLCHigh, LCIHigh/RV/TLCLow, and LCILow/RV/TLCLow).

RESULTS

Data from 127 adults with clinically stable bronchiectasis were analyzed. LCI had greater diagnostic value than RV/TLC in discriminating moderate-to-severe from mild bronchiectasis, had greater concordance in reflecting clinical characteristics (including the number of bronchiectatic lobes, radiological severity score, and the presence of cystic bronchiectasis). Normalization of LCI with RV/TLC did not contribute to greater discriminative performance or concordance with clinical variables. The LCI, before and after normalization with RV/TLC, correlated statistically with age, sex, HRCT score, Pseudomonas aeruginosa colonization, cystic bronchiectasis, and ventilation heterogeneity (all P<0.05). Different bronchodilator responses were not significant among the four subgroups of bronchiectasis patients, including those with discordant LCI and RV/TLC levels.

CONCLUSION

LCI is superior to RV/TLC for bronchiectasis assessment. Normalization with RV/TLC is not required. Stratification of LCI and RV/TLC is not associated with significantly different bronchodilator responses.

The quantitative link of lung clearance index to bronchial segments affected by bronchiectasis

In adult patients with cystic fibrosis (CF), the lung clearance index (LCI) derived from the multiple breath washout relates to both acinar and conductive ventilation heterogeneity. The latter component predicts an association between LCI and the number of bronchial segments affected by bronchiectasis. Here, we experimentally demonstrated this association in patients with CF, and also examined an ancillary group of patients with non-CF bronchiectasis. We conclude that lung disease severity in terms of number of bronchial segments results in an associated LCI increase, likely constituting a portion of LCI that cannot be reversed by treatment in patients with CF lung disease.

Primary Ciliary Dyskinesia: An Update on Clinical Aspects, Genetics, Diagnosis, and Future Treatment Strategies

Primary ciliary dyskinesia (PCD) is an orphan disease (MIM 244400), autosomal recessive inherited, characterized by motile ciliary dysfunction. The estimated prevalence of PCD is 1:10,000 to 1:20,000 live-born children, but true prevalence could be even higher. PCD is characterized by chronic upper and lower respiratory tract disease, infertility/ectopic pregnancy, and situs anomalies, that occur in ≈50% of PCD patients (Kartagener syndrome), and these may be associated with congenital heart abnormalities. Most patients report a daily year-round wet cough or nose congestion starting in the first year of life. Daily wet cough, associated with recurrent infections exacerbations, results in the development of chronic suppurative lung disease, with localized-to-diffuse bronchiectasis. No diagnostic test is perfect for confirming PCD. Diagnosis can be challenging and relies on a combination of clinical data, nasal nitric oxide levels plus cilia ultrastructure and function analysis. Adjunctive tests include genetic analysis and repeated tests in ciliary culture specimens. There are currently 33 known genes associated with PCD and correlations between genotype and ultrastructural defects have been increasingly demonstrated. Comprehensive genetic testing may hopefully screen young infants before symptoms occur, thus improving survival. Recent surprising advances in PCD genetic designed a novel approach called "gene editing" to restore gene function and normalize ciliary motility, opening up new avenues for treating PCD. Currently, there are no data from randomized clinical trials to support any specific treatment, thus, management strategies are usually extrapolated from cystic fibrosis. The goal of treatment is to prevent exacerbations, slowing the progression of lung disease. The therapeutic mainstay includes airway clearance maneuvers mainly with nebulized hypertonic saline and chest physiotherapy, and prompt and aggressive administration of antibiotics. Standardized care at specialized centers using a multidisciplinary approach that imposes surveillance of lung function and of airway biofilm composition likely improves patients' outcome. Pediatricians, neonatologists, pulmonologists, and ENT surgeons should maintain high awareness of PCD and refer patients to the specialized center before sustained irreversible lung damage develops. The recent creation of a network of PCD clinical centers, focusing on improving diagnosis and treatment, will hopefully help to improve care and knowledge of PCD patients.

Lung structure and function similarities between primary ciliary dyskinesia and mild cystic fibrosis: a pilot study

Background

Primary ciliary dyskinesia (PCD) and cystic fibrosis (CF) are increasingly compared. There are no chest magnetic resonance imaging (MRI) comparative studies of PCD and CF. We assessed clinical, functional, microbiological and MRI findings in PCD and mild CF patients in order to evaluate different expression of lung disease.

Methods

Twenty PCD (15.1 years) and 20 CF subjects with mild respiratory impairment (16 years, 70% with pancreatic insufficiency) underwent MRI, spirometry, and sputum cultures when clinically stable. MRI was scored using the modified Helbich system.

Results

PCD was diagnosed later than CF (9.9 versus 0.6 years, p = 0.03), despite earlier symptoms (0.1 versus 0.6 years, p = 0.02). In the year preceding the study, patients from both groups underwent two systemic antibiotic courses (p = 0.48). MRI total scores were 11.6 ± 0.7 and 9.1 ± 1 in PCD and CF, respectively. FEV₁ and FVC Z-scores were −1.75 (range, −4.6–0.7) and −0.6 (−3.9–1.8) in PCD, and −0.9 (range, −5.4–2.3) and −0.3 (−3.4–2.5) in CF, respectively. No difference was found between lung function or structure, despite a higher MRI subscore of collapse/consolidation in PCD versus CF (1.6 ± 0.1 and 0.6 ± 0.2, p < 0.001). These findings were confirmed after data-control for diagnostic delay. Pseudomonas aeruginosa and Staphylococcus aureus were more frequent in CF than in PCD (p = 0.05 and p = 0.003, respectively).

Conclusions

MRI is a valuable radiation-free tool for comparative PCD and CF lung disease assessment. Patients with PCD may exhibit similar MRI and lung function changes as CF subjects with mild pulmonary disease. Delay in PCD diagnosis is unlikely the only determinant of similarities.

Electronic supplementary material

The online version of this article (doi:10.1186/s13052-017-0351-2) contains supplementary material, which is available to authorized users.

Developments in multiple breath washout testing in children with cystic fibrosis

BACKGROUND

Lung clearance index (LCI) is becoming recognized as an important addition in the monitoring of pediatric cystic fibrosis (CF). The non-invasive technique is easy to perform in all ages, reproducible and increasingly being used in clinical trials. There is interest in utilizing it within the clinic setting but its current use is mostly as a research tool. The procedure is highly dependent on skilled operators and a relaxed testing environment is key to obtaining good quality measurements.

CONCLUSIONS

Standardization of LCI is part of an ongoing collaborative, multicenter process. This review describes the background to LCI, discusses technical issues and limitations and provides examples of its utility in clinical and research contexts.

The patient's experience of primary ciliary dyskinesia: a systematic review

Background

Primary ciliary dyskinesia (PCD) is a rare genetic disorder characterised by progressive sinopulmonary disease, with symptoms starting soon after birth. The aim of this study is to critically review, analyse, and synthesise the literature in order to understand the experiences of patients with primary ciliary dyskinesia (PCD) and the impact on health-related quality of life.

Method

MEDLINE, EBSCO, Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycINFO and EMBASE were searched according to the inclusion criteria. A qualitative analysis of 14 studies was conducted.

Results

Fourteen studies were included in the review, five with qualitative methodologies. Studies originated from the UK, USA, Italy, Denmark and Belgium, one study included a survey distributed internationally. Significant relationships were found between age and worsening of respiratory symptoms, physical, and mental domains of health-related quality of life, with a greater decline compared with reference populations. Variations between the UK and Italy were found for health-related quality of life and its correlation with time since diagnosis. PCD was found to have a physical impact in all age groups: patients found it difficult to keep up with others, and found energy levels were easily depleted compared to family or peers. In terms of social impact, symptoms lead to embarrassment and a sense of isolation, with patients concealing symptoms and/or their diagnosis. In turn, isolation was also linked with the lack of public and medical knowledge. In relation to emotional impact, anxiety was reported in a number of qualitative studies; patients were anxious about getting sick or when thinking about their future health. The burden of treatment and factors influencing adherence were also discussed in depth.

Conclusion

Health-related quality of life decreases with age in patients with PCD. For all age groups, PCD was found to greatly impact physical, emotional, social functioning, and treatment burden. More research is needed on the psychosocial impact of the illness, disease burden and its effect on quality of life.

Validation of a health-related quality of life instrument for primary ciliary dyskinesia (QOL-PCD)

Background

Quality of life (QOL)-primary ciliary dyskinesia (PCD) is the first disease-specific, health-related QOL instrument for PCD. Psychometric validation of QOL-PCD assesses the performance of this measure in adults, including its reliability, validity and responsiveness to change.

Methods

Seventy-two adults (mean (range) age: 33 years (18–79 years); mean (range) FEV₁% predicted: 68 (26–115)) with PCD completed the 49-item QOL-PCD and generic QOL measures: Short-Form 36 Health Survey, Sino-Nasal Outcome Test 20 (SNOT-20) and St George Respiratory Questionnaire (SGRQ)-C. Thirty-five participants repeated QOL-PCD 10–14 days later to measure stability or reproducibility of the measure.

Results

Multitrait analysis was used to evaluate how the items loaded on 10 hypothesised scales: physical, emotional, role and social functioning, treatment burden, vitality, health perceptions, upper respiratory symptoms, lower respiratory symptoms and ears and hearing symptoms. This analysis of item-to-total correlations led to 9 items being dropped; the validated measure now comprises 40 items. Each scale had excellent internal consistency (Cronbach's α: 0.74 to 0.94). Two-week test–retest demonstrated stability for all scales (intraclass coefficients 0.73 to 0.96). Significant correlations were obtained between QOL-PCD scores and age and FEV₁. Strong relationships were also found between QOL-PCD scales and similar constructs on generic questionnaires, for example, lower respiratory symptoms and SGRQ-C (r=0.72, p<0.001), while weak correlations were found between measures of different constructs.

Conclusions

QOL-PCD has demonstrated good internal consistency, test–retest reliability, convergent and divergent validity. QOL-PCD offers a promising tool for evaluating new therapies and for measuring symptoms, functioning and QOL during routine care.

Alternative inert gas washout outcomes in patients with primary ciliary dyskinesia

The lung clearance index (LCI) derived from a nitrogen multiple breath washout test (N2-MBW) is a promising tool to assess small airways disease in primary ciliary dyskinesia, but it is difficult to apply in routine clinical settings because of its long measuring time. In this study, we aimed to assess alternative indices derived from shorter washout protocols.

49 patients with primary ciliary dyskinesia (mean age 14.7±6.6 years) and 37 controls (mean age 14.3±1.4 years) performed N2-MBW and double-tracer gas (DTG) single-breath washout tests. Global (LCI and moment ratio (M2/M0)), conductive (Scond) and acinar ventilation inhomogeneity (DTG Slope III (SIII-DTG)) were determined for each individual. The main outcomes were 1) the ability to detect abnormal lung function from washout indices (>1.64 z-scores) and 2) measurement duration.

The prevalence of abnormal values for LCI2.5% was 37 out of 47 (79%), for LCI5% was 34 out of 47 (72%), for M2/M0 was 34 out of 47 (72%), for Scond was 36 out of 46 (78%) and for SIII-DTG was 12 out of 35 (34%). Mean±sd duration of measurement was 19.8±11.2 min for LCI2.5%, 10.8±4.6 min for LCI5% and 8.6±2.3 min for Scond.

Compared to standard LCI2.5%, ventilation inhomogeneity was detected by LCI5%, moment ratio and Scond with comparable sensitivity while measurement duration was significantly shorter. Longitudinal studies will show which outcome is most suitable and practical in terms of sensitivity, duration and variability within the course of primary ciliary dyskinesia lung disease.

Key paediatric messages from the 2016 European Respiratory Society International Congress

In this article, the Group Chairs of the Paediatric Assembly of the European Respiratory Society (ERS) highlight some of the most interesting abstracts presented at the 2016 ERS International Congress, which was held in London.

Quality of Life Questionnaire for Turkish Patients with Primary Ciliary Dyskinesia

OBJECTIVES

Primary ciliary dyskinesia (PCD) is a major cause of progressive lung disease, and physiological measures do not reflect the impact of the disease on patients' daily symptoms or physical and social functions. We need valid and reliable health-related quality-of-life (HRQOL) measures in PCD to assess the symptoms and daily functions from the patient's perspective. Our aim was to develop a Turkish translation of PCD-specific HRQOL questionnairre to be used as outcomes in clinical trials.

MATERIAL AND METHODS

This study was conducted at the Division of Pediatric Pulmonology, Hacettepe University Faculty of Medicine and the Division of Pediatric Pulmonology, Marmara University Faculty of Medicine. Forward and back translations were performed by three different translators. We recruited participants with PCD from different age groups of both sexes, with an aim to represent a wide spectrum of disease severity and performed the prototype of the translation in these participants.

RESULTS

Five participants from each age group [children (6-12 years), teenagers (13-17 years), adults (18+ years) and parents of children aged from 6 to 12 years] responded to the HRQOL questionnaire. Content analysis of the questions included the following domains depending on age: Respiratory Symptoms, Physical Functioning, Emotional Functioning, Treatment Burden, Ears and Hearing, Sinus Symptoms, Social Functioning, Role Functioning, Vitality, Health Perceptions, School Functioning, Eating and Weight. After the participants have completed the questionnaire, a cognitive debriefing interview was conducted with them, and the results of the interviews were used to form a final version of PCD-specific HRQOL, ready for formal validation.

CONCLUSION

A Turkish translation of PCD-specific HRQOL questionnaire was developed to meet the standards set by international guidelines. This questionnaire is expected to be useful as end points in clinical trials for monitoring health outcomes and for improving clinical decisions.

Proceedings of the COST action BM1407 inaugural conference BEAT-PCD: translational research in primary ciliary dyskinesia - bench, bedside, and population perspectives

Primary ciliary dyskinesia (PCD) is a rare heterogenous condition that causes progressive suppurative lung disease, chronic rhinosinusitis, chronic otitis media, infertility and abnormal situs. 'Better Experimental Approaches to Treat Primary Ciliary Dyskinesia' (BEAT-PCD) is a network of scientists and clinicians coordinating research from basic science through to clinical care with the intention of developing treatments and diagnostics that lead to improved long-term outcomes for patients. BEAT-PCD activities are supported by EU Framework Programme Horizon 2020 funded COST Action (BM1407). The Inaugural Conference of BEAT-PCD was held in December 2015 in Southampton, UK. The conference attracted ninety-six scientists, clinicians, allied health professionals, industrial partners and patient representatives from twenty countries. We aimed to identify the needs for PCD research and clinical care, particularly focussing on basic science, epidemiology, diagnostic testing, clinical management and clinical trials. The multidisciplinary conference provided an interactive platform for exchanging ideas through a program of lectures, poster presentations, breakout sessions and workshops. This allowed us to develop plans for collaborative studies. In this report, we summarize the meeting, highlight developments, and discuss open questions thereby documenting ongoing developments in the field of PCD research.

Lung Clearance Index (LCI) in Patients with Bronchiolitis Obliterans: A Preliminary Report and Comparison to Cystic Fibrosis Patients

INTRODUCTION

Bronchiolitis obliterans (BO) is a chronic airway disease following an insult to the lower respiratory tract. Lung clearance index (LCI) measures ventilation inhomogeneity and has been studied in cystic fibrosis (CF). We aimed to evaluate LCI in BO and to compare it to LCI in CF patients.

METHODS

LCI was measured in BO patients, compared to CF patients, and correlated with spirometry and CT findings.

RESULTS

Twenty BO patients and 26 CF patients (with similar mean age and BMI) underwent evaluation. FEV1 % and FEF25-75 % predicted were significantly lower in the BO group (60.5 ± 17.8 vs. 72.7 ± 20.7, p = 0.041, and 42.8 ± 22.8 vs. 66.4 ± 37.4, p = 0.017, respectively). In both groups, LCI was inversely correlated with FVC %, FEV1 %, and FEF25-75 % predicted. LCI  % was slightly higher (190.4 ± 63.5 vs. 164.9 ± 39.4, p = 0.1) and FRC gas % (measured by multiple breath washout) was significantly higher in the BO group (92.5 ± 35.9 vs. 71.3 ± 18, p = 0.014). The strength of statistical association between the lower FEF25-75 % values and the higher LCI values was stronger in BO patients.

CONCLUSIONS

Similar to CF, LCI may provide estimation of ventilation inhomogeneity in BO. The results indicate greater small airway involvement and air trapping in BO. Further prospective longitudinal studies evaluating the correlation of LCI measurements with multiple clinical and physiological parameters should be performed to assess the clinical benefit of LCI measurement in BO.

Study protocol, rationale and recruitment in a European multi-centre randomized controlled trial to determine the efficacy and safety of azithromycin maintenance therapy for 6 months in primary ciliary dyskinesia

Background

Clinical management of primary ciliary dyskinesia (PCD) respiratory disease is currently based on improving mucociliary clearance and controlling respiratory infections, through the administration of antibiotics. Treatment practices in PCD are largely extrapolated from more common chronic respiratory disorders, particularly cystic fibrosis, but no randomized controlled trials (RCT) have ever evaluated efficacy and safety of any pharmacotherapeutics used in the treatment of PCD. Maintenance therapy, with the macrolide antibiotic azithromycin, is currently widely used in chronic respiratory diseases including PCD. In addition to its antibacterial properties, azithromycin is considered to have beneficial anti-inflammatory and anti-quorum-sensing properties.

The aim of this study is to determine the efficacy of azithromycin maintenance therapy for 6 months on respiratory exacerbations in PCD. The secondary objectives are to evaluate the efficacy of azithromycin on lung function, ventilation inhomogeneity, hearing impairment, and symptoms (respiratory, sinus, ears and hearing) measured on a PCD-specific health-related quality of life instrument, and to assess the safety of azithromycin maintenance therapy in PCD.

Methods

The BESTCILIA trial is a European multi-centre, double-blind, randomized, placebo-controlled, parallel group study. The intervention is tablets of azithromycin 250/500 mg according to body weight or placebo administered three times a week for 6 months. Subjects with a confirmed diagnosis of PCD, age 7–50 years, are eligible for inclusion. Chronic pulmonary infections with Gram-negative bacteria or any recent occurrence of non-tuberculous mycobacteria are exclusion criteria. The planned number of subjects to be included is 125. The trial has been approved by the Research Ethics Committees of the participating institutions.

Discussion

We present a study protocol of an ongoing RCT, evaluating for the first time, the efficacy and safety of a pharmacotherapeutic treatment for patients with PCD. The RCT evaluates azithromycin maintenance therapy, a drug already commonly prescribed in other chronic respiratory disorders. Furthermore, the trial will utilize the Lung clearance index and new, PCD-specific quality of life instruments as outcome measures for PCD. Recruitment is hampered by frequent occurrence of Pseudomonas aeruginosa infection, exacerbations at enrolment, and the patients’ perception of disease severity and necessity of additional management and treatment during trial participation.

Trial registration

EudraCT 2013-004664-58 (date of registration: 2014-04-08).

Feasibility of lung clearance index in a clinical setting in pre-school children

Lung function testing in pre-school children in the clinical setting is challenging. Most cannot perform spirometry and many infant lung function tests require sedation. Lung clearance index (LCI) derived from the multiple-breath washout (MBW) test has been shown to be sensitive to early disease changes but may be time consuming and so a shortened test (LCI_0.5) may be more feasible in young children. We sought to establish feasibility of MBW in unsedated pre-school children in a clinic setting and hypothesised use of LCI_0.5 would increase success rates.116 pre-school children (28 healthy controls and 88 with respiratory disease), median age 4.0 years (range 2-6 years), underwent MBW tests unsedated in a clinic setting, using sulfur hexafluoride as a tracer gas and an adapted photoacoustic gas analyser.81 (70%) out of 116 children completed LCI and 72% completed LCI_0.5 measurement. Test success increased significantly in patients over 3 years (0% at <2.5 years, 33% at 2.5-3 years and 70% at >3 years, p<0.0001). LCI was elevated in those with respiratory disease compared with healthy controls.MBW is feasible in a clinic setting in unsedated pre-schoolers, particularly in those >3 years old, and LCI is raised in those with respiratory disease. Use of LCI_0.5 did not increase success rate in pre-schoolers.

Clinical characteristics, functional respiratory decline and follow-up in adult patients with primary ciliary dyskinesia

INTRODUCTION

Primary ciliary dyskinesia (PCD) is a genetic disease characterised by abnormalities in ciliary function, responsible for chronic pulmonary and sinonasal diseases. Adult clinical features and outcome are poorly described.

OBJECTIVES

To assess the clinical characteristics and disease progression in adults with PCD.

METHODS

Bicentric retrospective study, focusing on adults (≥18 years) with an asserted diagnosis of PCD based on the presence of bronchiectasis with typical ultrastructural defect of cilia and/or situs inversus (SI). Clinical symptoms, respiratory function, extent of bronchiectasis, microbiology and molecular analysis were assessed. Results are expressed as median (25th; 75th centile).

RESULTS

78 patients were included with a median follow-up of 8.1 years. 91% of patients had respiratory symptoms and 95% had chronic rhinosinusitis. Half of ultrastructural defects concerned dynein arms. Respiratory function was significantly lower in women (FEV₁=60% predicted (50; 76), vs 77% (62; 95), p=0.009) and in patients with chronic airway Pseudomonas aeruginosa (PA, n=21) infection (FEV₁=60% (48; 71) vs 75% (55; 89), p=0.04). FEV₁ was associated with gender (regression coefficient for men =13.8, p=0.009), chest CT score (r=-0.42, p<0.001) but not with age at diagnosis, SI or body mass index. FEV₁ decline was -13.4 mL/year (-42.8; +11.9) and was greater in women (-29.3 mL/year, (-59.7; -11.9), vs -2.0 mL/year (-26.9; +25.4), p=0.002). Three patients had severe respiratory failure.

CONCLUSIONS

Alteration of respiratory function in adults with PCD is heterogeneous and usually moderate but appears more severe in women and in patients with chronic PA infection. Only 4% of patients develop chronic respiratory failure.