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

Lung ultrasound in children with primary ciliary dyskinesia or cystic fibrosis

INTRODUCTION

Primary ciliary dyskinesia (PCD) and cystic fibrosis (CF) are respiratory conditions requiring regular chest radiography (CXR) surveillance to monitor pulmonary disease. However, CXR is insensitive for lung disease in CF and PCD. Lung ultrasound (LU) is a radiation-free alternative showing good correlation with severity of lung disease in CF but has not been studied in PCD.

METHOD

Standardized, six-zone LU studies and CXR were performed on a convenience sample of children with PCD or CF during a single visit when well. LU studies were graded using the LU scoring system, while CXR studies received a modified Chrispin-Norman score. Scores were correlated with clinical outcomes.

RESULT

Data from 30 patients with PCD and 30 with CF (median age PCD 11.5 years, CF 9.1 years) with overall mild pulmonary disease (PCD median FEV1 90% predicted, CF FEV1 100%) were analyzed. LU abnormalities appear in 11/30 (36%) patients with PCD and 9/30 (30%) with CF. Sensitivity, specificity, positive predictive, and negative predictive values for abnormal LU compared to the gold standard of CXR are 42%, 61%, 42%, and 61% in PCD, and 44%, 81%, 50%, and 77% in CF, respectively. Correlation between LU and CXR scores are poor for both diseases (PCD r = -0.1288, p = 0.4977; CF r = 0.0343, p = 0.8571), and LU score does not correlate with clinical outcomes in PCD.

CONCLUSION

The correlation of LU findings with CXR surveillance studies is poor in patients with mild disease burdens from PCD or CF, and LU scores do not correlate with clinical outcomes 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.

Cystic fibrosis and primary ciliary dyskinesia: Similarities and differences

Cystic fibrosis (CF) and Primary ciliary dyskinesia (PCD) are both rare chronic diseases, inherited disorders associated with multiple complications, namely respiratory complications, due to impaired mucociliary clearance that affect severely patients' lives. Although both are classified as rare diseases, PCD has a much lower prevalence than CF, particularly among Caucasians. As a result, CF is well studied, better recognized by clinicians, and with some therapeutic approaches already available. Whereas PCD is still largely unknown, and thus the approach is based on consensus guidelines, expert opinion, and extrapolation from the larger evidence base available for patients with CF. Both diseases have some clinical similarities but are very different, necessitating different treatment by specialists who are familiar with the complexities of each disease.This review aims to provide an overview of the knowledge about the two diseases with a focus on the similarities and differences between both in terms of disease mechanisms, common clinical manifestations, genetics and the most relevant therapeutic options. We hoped to raise clinical awareness about PCD, what it is, how it differs from CF, and how much information is still lacking. Furthermore, this review emphasises the fact that both diseases require ongoing research to find better treatments and, in particular for PCD, to fill the medical and scientific gaps.

Psychological status of mothers of children with cystic fibrosis and primary ciliary dyskinesia

OBJECTIVES

We aimed to investigate depression, burnout, attitude, and burden of caregivers of children with cystic fibrosis (CF), and especially caregivers of children with primary ciliary dyskinesia (PCD) due to limited number of studies on this topic, and to compare them according to their children's clinical status.

METHODS

Clinical features and demographic data of children and their families were asked from caregivers in four pediatric pulmonology centers. Beck Depression Inventory, Maslach Burnout Inventory, Zarit Caregiver Burden Scale, and Parental Attitude Research Instrument were administered to caregivers in both groups. Results were compared between the two groups.

RESULTS

In total, 131 children with CF and 39 with PCD and their caregivers were involved in the study. All primary caregivers were mothers in both groups. Depression, burnout, and burden scores of mothers of children with CF were significantly higher than mothers of children with PCD (p = 0.017, p = 0.024, p = 0.038, respectively). Burnout was higher in both CF and PCD groups with low family income (p = 0.022, p = 0.034). Number of hospital visits in the previous 6 months was correlated with burnout in both CF and PCD groups (r = 0.207, p = 0.034; r = 0.352, p = 0.044).

CONCLUSIONS

Although mothers with children with CF have higher levels of depression, burnout, burden, and negative attitudes toward children than mothers with children with PCD, these are also significantly high in mothers with children with PCD. Psychological problems of mothers of children with CF and PCD may increase with frequent hospital visits, hospitalizations, low family income, number of children, and chronic disease in another child.

Fissure adjacent partial lobe atelectasis in primary ciliary dyskinesia

AIM

Establishing the underlying cause in a child with chronic suppurative lung disease (CSLD) allows for targeted treatment and screening for associated complications. One cause of CSLD is primary ciliary dyskinesia (PCD). Testing for PCD requires specialist expertise which is not widely available. Computed tomography (CT) scans are commonly performed when assessing CSLD. Identifying PCD-specific signs on CT would help clinicians in deciding when to refer for specialist testing. One potential PCD-specific sign we have observed is fissure adjacent partial lobe atelectasis (FAPLA). We aimed to assess if FAPLA is commonly found in CT of PCD patients.

METHODS

Fifty-eight CT scans from 42 adult and child PCD patients were analysed. The presence and distribution of FAPLA were noted, and its association to sputum culture and other signs commonly seen in CSLD (bronchiectasis, bronchial wall thickening, air trapping and mucus plugging).

RESULTS

FAPLA was found in 13 of 40 participants in their earliest CT scan. The prevalence of FAPLA was similar in children and adults. FAPLA involved the right middle lobe in all 13 cases and was systematically associated with ≥1 other structural change. There was no association between FAPLA and bacterial isolation from sputum.

CONCLUSION

FAPLA was found in 32.5% PCD scans, without difference between children and adults in terms of frequency. Future work will determine if it is a PCD-specific sign by assessing whether it is also found in other CSLD processes and analysing more scans from children with PCD to determine how early this sign develops.

Quantitative analysis of changes in lung density by dynamic chest radiography in association with CT values: a virtual imaging study and initial clinical corroboration

Dynamic chest radiography (DCR) identifies pulmonary impairments as decreased changes in radiographic lung density during respiration (Δpixel values), but not as scaled/standardized computed tomography (CT) values. Quantitative analysis correlated with CT values is beneficial for a better understanding of Δpixel values in DCR-based assessment of pulmonary function. The present study aimed to correlate Δpixel values from DCR with changes in CT values during respiration (ΔCT values) through a computer-based phantom study. A total of 20 four-dimensional computational phantoms during forced breathing were created to simulate both CT and projection images of the same virtual patients. The Δpixel and ΔCT values of the lung fields were correlated on a regression line, and the inclination was statistically evaluated to determine whether there were significant differences among physical types, sex, and breathing methods. The resulting conversion expression was also assessed in the DCR images of 37 patients. The resulting Δpixel values for 30/37 (81%) real patients, 6/7 (86%) normal controls, and 24/30 (80%) chronic obstructive pulmonary disorder patients were within the range of ΔCT values ± standard deviation (SD) reported in a previous study. In addition, no significant differences were detected for each condition of thoracic breathing, suggesting that the same regression line inclination values measured across the entire lung can be used for the conversion of Δpixel values, providing a quantitative analysis that can be correlated with ΔCT values. The developed conversion expression may be helpful for improving the understanding of respiratory changes using radiographic lung densities from DCR-based assessments of pulmonary function.

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.

Prevalence and course of disease after lung resection in primary ciliary dyskinesia: a cohort & nested case-control study

Background

Lung resection is a controversial and understudied therapeutic modality in Primary Ciliary Dyskinesia (PCD). We assessed the prevalence of lung resection in PCD across countries and compared disease course in lobectomised and non-lobectomised patients.

Methods

In the international iPCD cohort, we identified lobectomised and non-lobectomised age and sex-matched PCD patients and compared their characteristics, lung function and BMI cross-sectionally and longitudinally.

Results

Among 2896 patients in the iPCD cohort, 163 from 20 centers (15 countries) underwent lung resection (5.6%). Among adult patients, prevalence of lung resection was 8.9%, demonstrating wide variation among countries. Compared to the rest of the iPCD cohort, lobectomised patients were more often females, older at diagnosis, and more often had situs solitus. In about half of the cases (45.6%) lung resection was performed before presentation to specialized PCD centers for diagnostic work-up. Compared to controls (n = 197), lobectomised patients had lower FVC z-scores (− 2.41 vs − 1.35, p = 0.0001) and FEV1 z-scores (− 2.79 vs − 1.99, p = 0.003) at their first post-lung resection assessment. After surgery, lung function continued to decline at a faster rate in lobectomised patients compared to controls (FVC z-score slope: − 0.037/year Vs − 0.009/year, p = 0.047 and FEV1 z-score slope: − 0.052/year Vs − 0.033/year, p = 0.235), although difference did not reach statistical significance for FEV1. Within cases, females and patients with multiple lobe resections had lower lung function.

Conclusions

Prevalence of lung resection in PCD varies widely between countries, is often performed before PCD diagnosis and overall is more frequent in patients with delayed diagnosis. After lung resection, compared to controls most lobectomised patients have poorer and continuing decline of lung function despite lung resection. Further studies benefiting from prospective data collection are needed to confirm these findings.

Thoracic calcifications on magnetic resonance imaging: correlations with computed tomography

OBJECTIVE

To identify the characteristics of thoracic calcifications on magnetic resonance (MR) imaging, as well as correlations between MR imaging and CT findings.

METHODS

This was a retrospective study including data on 62 patients undergoing CT scans and MR imaging of the chest at any of seven hospitals in the Brazilian states of Rio Grande do Sul, São Paulo, and Rio de Janeiro between March of 2014 and June of 2016 and presenting with calcifications on CT scans. T1- and T2-weighted MR images (T1- and T2-WIs) were semiquantitatively analyzed, and the lesion-to-muscle signal intensity ratio (LMSIR) was estimated. Differences between neoplastic and non-neoplastic lesions were analyzed.

RESULTS

Eighty-four calcified lesions were analyzed. Mean lesion density on CT was 367 ± 435 HU. Median LMSIRs on T1- and T2-WIs were 0.4 (interquartile range [IQR], 0.1-0.7) and 0.2 (IQR, 0.0-0.7), respectively. Most of the lesions were hypointense on T1- and T2-WIs (n = 52 [61.9%] and n = 39 [46.4%], respectively). In addition, 19 (22.6%) were undetectable on T1-WIs (LMSIR = 0) and 36 (42.9%) were undetectable on T2-WIs (LMSIR = 0). Finally, 15.5% were hyperintense on T1-WIs and 9.5% were hyperintense on T2-WIs. Median LMSIR was significantly higher for neoplastic lesions than for non-neoplastic lesions. There was a very weak and statistically insignificant negative correlation between lesion density on CT and the following variables: signal intensity on T1-WIs, LMSIR on T1-WIs, and signal intensity on T2-WIs (r = -0.13, p = 0.24; r = -0.18, p = 0.10; and r = -0.16, p = 0.16, respectively). Lesion density on CT was weakly but significantly correlated with LMSIR on T2-WIs (r = -0.29, p < 0.05).

CONCLUSIONS

Thoracic calcifications have variable signal intensity on T1- and T2-weighted MR images, sometimes appearing hyperintense. Lesion density on CT appears to correlate negatively with lesion signal intensity on MR images.

Primary Ciliary Dyskinesia: Longitudinal Study of Lung Disease by Ultrastructure Defect and Genotype

RATIONALE

In primary ciliary dyskinesia, factors leading to disease heterogeneity are poorly understood.

OBJECTIVES

To describe early lung disease progression in primary ciliary dyskinesia and identify associations between ultrastructural defects and genotypes with clinical phenotype.

METHODS

This was a prospective, longitudinal (5 yr), multicenter, observational study. Inclusion criteria were less than 19 years at enrollment and greater than or equal to two annual study visits. Linear mixed effects models including random slope and random intercept were used to evaluate longitudinal associations between the ciliary defect group (or genotype group) and clinical features (percent predicted FEV1 and weight and height z-scores).

MEASUREMENTS AND MAIN RESULTS

A total of 137 participants completed 732 visits. The group with absent inner dynein arm, central apparatus defects, and microtubular disorganization (IDA/CA/MTD) (n = 41) were significantly younger at diagnosis and in mixed effects models had significantly lower percent predicted FEV1 and weight and height z-scores than the isolated outer dynein arm defect (n = 55) group. Participants with CCDC39 or CCDC40 mutations (n = 34) had lower percent predicted FEV1 and weight and height z-scores than those with DNAH5 mutations (n = 36). For the entire cohort, percent predicted FEV1 decline was heterogeneous with a mean (SE) decline of 0.57 (0.25) percent predicted/yr. Rate of decline was different from zero only in the IDA/MTD/CA group (mean [SE], -1.11 [0.48] percent predicted/yr; P = 0.02).

CONCLUSIONS

Participants with IDA/MTD/CA defects, which included individuals with CCDC39 or CCDC40 mutations, had worse lung function and growth indices compared with those with outer dynein arm defects and DNAH5 mutations, respectively. The only group with a significant lung function decline over time were participants with IDA/MTD/CA defects.

Lung function in patients with primary ciliary dyskinesia: an iPCD Cohort study

Primary ciliary dyskinesia (PCD) has been considered a relatively mild disease, especially compared to cystic fibrosis (CF), but studies on lung function in PCD patients have been few and small.This study compared lung function from spirometry of PCD patients to normal reference values and to published data from CF patients. We calculated z-scores and % predicted values for forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC) using the Global Lung Function Initiative 2012 values for 991 patients from the international PCD Cohort. We then assessed associations with age, sex, country, diagnostic certainty, organ laterality, body mass index and age at diagnosis in linear regression models. Lung function in PCD patients was reduced compared to reference values in both sexes and all age groups. Children aged 6-9 years had the smallest impairment (FEV₁ z-score -0.84 (-1.03 to -0.65), FVC z-score -0.31 (-0.51 to -0.11)). Compared to CF patients, FEV₁ was similarly reduced in children (age 6-9 years PCD 91% (88-93%); CF 90% (88-91%)), but less impaired in young adults (age 18-21 years PCD 79% (76-82%); CF 66% (65-68%)). The results suggest that PCD affects lung function from early in life, which emphasises the importance of early standardised care for all patients.

Bronchiectasis in PCD looks different to CF on CT scan

The contemporary diagnosis of bronchiectasis requires CT scanning to describe specific structural lung changes. Scoring systems have been designed and validated in some specific causes of bronchiectasis to allow investigators to correlate CT changes with other indices of disease severity, to describe changes over time, with exacerbation and in response to treatment. Several scoring systems have been developed for CF including the Bhalla Score, Brody score, and the Helbich score. These scoring systems have also been applied to other causes of bronchiectasis including Primary Ciliary Dyskinesia (PCD). This assumes that the nature of structural lung disease in these conditions, as well as the rate and nature of longitudinal changes are identical to, or at least very similar to, those found in CF. This assumption has not been tested. The underlying pathophysiology of PCD is not the same as CF and may cause bronchiectasis that is radiologically similar but not necessarily the same as CF or any other cause of bronchiectasis. The development of a disease specific scoring system for structural change in cases of non-CF bronchiectasis due to any cause, would require consideration of the full range of changes seen in that condition without reference to changes seen in other conditions. We present a summary of structural findings that have been described in PCD and highlight the radiological differences between PCD and other causes of bronchiectasis. We suggest that a PCD specific CT scoring system is required to properly describe changes seen in PCD.

A pediatric disease to keep in mind: diagnostic tools and management of bronchiectasis in pediatric age

Bronchiectasis in pediatric age is a heterogeneous disease associated with significant morbidity.The most common medical conditions leading to bronchial damage are previous pneumonia and recurrent lower airway infections followed by underlying diseases such as immune-deficiencies, congenital airway defects, recurrent aspirations and mucociliary clearance disorders.The most frequent symptom is chronic wet cough. The introduction of high-resolution computed tomography (HRCT) has improved the time of diagnosis allowing earlier treatment.However, the term "bronchiectasis" in pediatric age should be used with caution, since some lesions highlighted with HRCT may improve or regress. The use of chest magnetic resonance imaging (MRI) as a radiation-free technique for the assessment and follow-up of lung abnormalities in non-Cystic Fibrosis chronic lung disease is promising.Non-Cystic Fibrosis Bronchiectasis management needs a multi-disciplinary team. Antibiotics and airway clearance techniques (ACT) represent the pillars of treatment even though guidelines in children are lacking. The Azithromycin thanks to its antinflammatory and direct antimicrobial effect could be a new strategy to prevent exacerbations.