The Swiss Primary Ciliary Dyskinesia registry: objectives, methods and first results

Primary ciliary dyskinesia (PCD) is a rare, hereditary, multiorgan disease caused by defects in the structure and function of motile cilia. It results in a wide range of clinical manifestations, most commonly in the upper and lower airways. Central data collection in national and international registries is essential to studying the epidemiology of rare diseases and filling in gaps in knowledge of diseases such as PCD. For this reason, the Swiss Primary Ciliary Dyskinesia Registry (CH-PCD) was founded in 2013 as a collaborative project between epidemiologists and adult and paediatric pulmonologists. We describe the objectives and methodology of the CH-PCD, present initial results, and give an overview of current and ongoing projects. The registry records patients of any age, suffering from PCD, who are treated and resident in Switzerland. It collects information from patients identified through physicians, diagnostic facilities and patient organisations. The registry dataset contains data on diagnostic evaluations, lung function, microbiology and imaging, symptoms, treatments and hospitalisations. By May 2018, CH-PCD has contacted 566 physicians of different specialties and identified 134 patients with PCD. At present, this number represents an overall 1 in 63,000 prevalence of people diagnosed with PCD in Switzerland. Prevalence differs by age and region; it is highest in children and adults younger than 30 years, and in Espace Mittelland. The median age of patients in the registry is 25 years (range 5–73), and 41 patients have a definite PCD diagnosis based on recent international guidelines. Data from CH-PCD are contributed to international collaborative studies and the registry facilitates patient identification for nested studies. CH-PCD has proven to be a valuable research tool that already has highlighted weaknesses in PCD clinical practice in Switzerland. Trial registration number: NCT03606200

The Swiss Primary Ciliary Dyskinesia registry: objectives, methods and first results

Primary ciliary dyskinesia (PCD) is a rare, hereditary, multiorgan disease caused by defects in the structure and function of motile cilia. It results in a wide range of clinical manifestations, most commonly in the upper and lower airways. Central data collection in national and international registries is essential to studying the epidemiology of rare diseases and filling in gaps in knowledge of diseases such as PCD. For this reason, the Swiss Primary Ciliary Dyskinesia Registry (CH-PCD) was founded in 2013 as a collaborative project between epidemiologists and adult and paediatric pulmonologists. We describe the objectives and methodology of the CH-PCD, present initial results, and give an overview of current and ongoing projects. The registry records patients of any age, suffering from PCD, who are treated and resident in Switzerland. It collects information from patients identified through physicians, diagnostic facilities and patient organisations. The registry dataset contains data on diagnostic evaluations, lung function, microbiology and imaging, symptoms, treatments and hospitalisations. By May 2018, CH-PCD has contacted 566 physicians of different specialties and identified 134 patients with PCD. At present, this number represents an overall 1 in 63,000 prevalence of people diagnosed with PCD in Switzerland. Prevalence differs by age and region; it is highest in children and adults younger than 30 years, and in Espace Mittelland. The median age of patients in the registry is 25 years (range 5–73), and 41 patients have a definite PCD diagnosis based on recent international guidelines. Data from CH-PCD are contributed to international collaborative studies and the registry facilitates patient identification for nested studies. CH-PCD has proven to be a valuable research tool that already has highlighted weaknesses in PCD clinical practice in Switzerland. Trial registration number NCT03606200

False normal Lung Clearance Index in infants with cystic fibrosis due to software algorithms

BACKGROUND

Lung clearance index (LCI), a marker of ventilation inhomogeneity, is elevated early in children with cystic fibrosis (CF). However, in infants with CF, LCI values are found to be normal, although structural lung abnormalities are often detectable. We hypothesized that this discrepancy is due to inadequate algorithms of the available software package.

AIM

Our aim was to challenge the validity of these software algorithms.

METHODS

We compared multiple breath washout (MBW) results of current software algorithms (automatic modus) to refined algorithms (manual modus) in 17 asymptomatic infants with CF, and 24 matched healthy term-born infants. The main difference between these two analysis methods lies in the calculation of the molar mass differences that the system uses to define the completion of the measurement.

RESULTS

In infants with CF the refined manual modus revealed clearly elevated LCI above 9 in 8 out of 35 measurements (23%), all showing LCI values below 8.3 using the automatic modus (paired t-test comparing the means, P < 0.001). Healthy infants showed normal LCI values using both analysis methods (n = 47, paired t-test, P = 0.79). The most relevant reason for false normal LCI values in infants with CF using the automatic modus was the incorrect recognition of the end-of-test too early during the washout.

CONCLUSION

We recommend the use of the manual modus for the analysis of MBW outcomes in infants in order to obtain more accurate results. This will allow appropriate use of infant lung function results for clinical and scientific purposes.

Idiopathic desquamative interstitial pneumonia in a child: a case report

Background

Desquamative interstitial pneumonia is a rare form of interstitial lung disease in children. Respiratory symptoms appear progressively, are often subtle, and diagnosis is often delayed by a mean of 6 months after onset. High resolution chest computed tomography is the most sensitive imaging technique for demonstrating and identifying interstitial pneumonia. The typical histologic pattern of desquamative interstitial pneumonia, with prominent clustered alveolar macrophages, diffuse reactive alveolar epithelial hyperplasia and globular proteinaceous material, is diagnostic. Desquamative interstitial pneumonia in children can be idiopathic, though it is mostly related to an inborn error of surfactant metabolism.

Case presentation

We present the complex clinical course and pathologic findings of a 30-months-old Mauritian and Senegalese girl with idiopathic desquamative interstitial pneumonia and multiple extrapulmonary manifestations. To our knowledge, this is the first case report of desquamative interstitial pneumonia to occur as part of a syndrome with multiple organ involvement.

Conclusion

We believe that desquamative interstitial pneumonia is not always associated with mutations of the surfactant proteins, and can still be idiopathic, especially when occurring as part of a syndrome with multiple organ involvement, as described in other interstitial lung diseases.

[Former preterm infant with bronchopulmonary dysplasia: how will this be cared for in 2014?]

Major improvements in perinatal care have led to increased survival after premature birth and have allowed the survival of very young and immature newborns. Bronchopulmonary dysplasia is a serious complication of prematurity and has become a developmental lung disorder, hardly preventable due to its multiple causes. The treatment serves to maintain a normal growth, reduce the respiratory workload, and prevent further complications, by trying not to interfer with postnatal lung development. Bronchopulmonary dysplasia may be associated with bronchial hyperreactivity and an obstructive bronchial pattern that may lead to frequent hospital admissions for reactive airway disease in the small child, and contribute to the persistence of chronic lung disease mainly as a new chronic obstructive pulmonary disease phenotype in adulthood.

[Pediatrics. New treatment options for viral bronchiolitis]

The combination of nebulized epinephrine and high dose dexamethasone, or nebulized hypertonic saline, are promising new therapeutic strategies for viral bronchiolitis in the young infant. However, further research is needed before a general recommendation can be given.

Respiratory symptoms in preterm infants: burden of disease in the first year of life

Objective

While respiratory symptoms in the first year of life are relatively well described for term infants, data for preterm infants are scarce. We aimed to describe the burden of respiratory disease in a group of preterm infants with and without bronchopulmonary dysplasia (BPD) and to assess the association of respiratory symptoms with perinatal, genetic and environmental risk factors.

Methods

Single centre birth cohort study: prospective recording of perinatal risk factors and retrospective assessment of respiratory symptoms during the first year of life by standardised questionnaires. Main outcome measures: Cough and wheeze (common symptoms), re-hospitalisation and need for inhalation therapy (severe outcomes). Patients: 126 preterms (median gestational age 28.7 weeks; 78 with, 48 without BPD) hospitalised at the University Children's Hospital of Bern, Switzerland 1999-2006.

Results

Cough occurred in 80%, wheeze in 44%, rehospitalisation in 25% and long term inhalation therapy in wheezers in 13% of the preterm infants. Using logistic regression, the main risk factor for common symptoms was frequent contact with other children. Severe outcomes were associated with maximal peak inspiratory pressure, arterial cord blood pH, APGAR and CRIB-Score.

Conclusions

Cough in preterm infants is as common as in term infants, whereas wheeze, inhalation therapy and re-hospitalisations occur more often. Severe outcomes are associated with perinatal risk factors. Preterm infants who did not qualify for BPD according to latest guidelines also showed a significant burden of respiratory disease in the first year of life.

[Implementation of the neonatal cystic fibrosis screening program in Switzerland: beginning January 2011]

The diagnosis of cystic fibrosis (CF) is often delayed because of the nonspecificity of a wide variety of clinical symptoms at disease onset. Newborn screening for CF has been advocated to reduce delays in diagnosis, facilitating preventive care for early respiratory and nutritional involvement. According to American and European consensus and experience of existing programs, a Swiss Nationwide Cystic Fibrosis Newborn Screening Program started in January 2011. Screening strategy combines two steps: an immunoreactive trypsinogen assay and DNA mutation analysis in dried blood samples at day 4 (Guthrie cards).

Mycoplasma hominis necrotizing pleuropneumonia in a previously healthy adolescent

Background

Mycoplasma hominis is a fastidious micro-organism causing systemic infections in the neonate and genital infections in the adult. It can also be the cause of serious extra-genital infections, mainly in immunosuppressed or predisposed subjects.

Case Presentation

We describe a case of severe pneumonia and pericarditis due to Mycoplasma hominis in a previously healthy adolescent who did not respond to initial therapy.

Conclusions

Mycoplasma hominis could be an underestimated cause of severe pneumonia in immunocompetent patients and should be particularly suspected in those not responding to standard therapy.

[How to investigate sleep related breathing disorders in children?]

Sleep related breathing disorders (SDB) in children has a major negative impact on their neurocognitive development and should be identified and treated early as to decrease morbidity. Children do not usually present daytime fatigue and sleepiness like adults, but rather show abnormal behavior patterns and learning disabilities. The presence of sustained nightime snoring is a good screening toll for SDB. Polysomnography is the gold standard for diagnosis even though nightime oxymetry, with its high positive predictive value, can also be used. The most frequent SDB in childhood is sleep obstructive apnea syndrome (SOAS), which generally requires surgical treatment with adenotonsillectomy. Long term evolution of pediatric SOAS still has to be defined, as the role of other diagnostic tools such as outpatient polygraphy.

Pseudomonas aeruginosa in public swimming pools and bathroom water of patients with cystic fibrosis

INTRODUCTION

Acquisition of Pseudomonas aeruginosa (PA) in the lungs of patients with cystic fibrosis (CF) is a marker of poor survival. PA is a ubiquitous pathogen prevalent in humid conditions. This study aimed to identify the prevalence of PA in public swimming pools, as well as from water taps.

METHODS

Water was collected from public indoor and outdoor pools in the area of St. Gallen, Switzerland. In addition, standing and running water was sampled from bathroom water taps of 50 patients with CF.

RESULTS

Outdoor pools: In 2002, none of the 72 specimens from 28 pools revealed PA. In 2003, three specimens from 46 pools (7%) revealed PA, each were from a different paddling pool. Indoor pools: two of 128 specimens from 56 pools (4%) identified PA, both were from non-public hydrotherapy pools. Water taps: in winter, none of the 102 specimens was colonized with PA. in summer, only two out of 50 specimens of the standing water were positive for PA but none of the running water revealed PA.

CONCLUSION

The prevalence of PA in public swimming pools and bathroom water taps in the eastern part of Switzerland is very low. On hot summer days, outdoor paddling pools and standing tap water can contain PA. This study does not support recommendations to avoid public swimming pools or running tap water if the water is maintained according to hygiene guidelines.

Plasma ionized magnesium during acute hyperventilation in humans

1. Respiratory alkalosis accompanies the clinical syndrome of tetany, precipitates cardiac arrhythmias and predisposes to coronary vasoconstriction. Magnesium plays a critical role in the maintenance of membrane function, and magnesium depletion is often associated with cardiac arrhythmias or vasoconstriction. 2. As technology for detecting circulating ionized magnesium (the most interesting form with respect to physiological and biological properties) is now available in the form of new magnesium-selective electrodes, the effect of respiratory alkalosis induced by voluntary overbreathing for 30 min on circulating ionized magnesium was studied in eight healthy subjects. 3. The total plasma magnesium concentration was not modified by hyperventilation. On the contrary, hyperventilation was associated with a significant reduction in the ionized magnesium concentration of 0.05 (0.02-0.15) mmol/l (median and range) and in the free magnesium fraction of 0.06 (0.01-0.19). During hyperventilation the relative intravascular magnesium mass, calculated from changes in total plasma magnesium concentration and haematocrit, decreased significantly. 4. It is concluded that acute overbreathing reduces the circulating ionized magnesium concentration and the intravascular magnesium mass. It is therefore conceivable that extracellular magnesium deficiency is at least a subsidiary cause of the syndrome of tetany and the cardiac complications that are precipitated by hyperventilation.