Diagnosis of Primary Ciliary Dyskinesia. An Official American Thoracic Society Clinical Practice Guideline

Additional role of bronchial mucosal biopsy for ciliary structural abnormality in diagnosis of primary ciliary dyskinesia

Background

Transmission electron microscopy (TEM) is one of diagnostic tests for primary ciliary dyskinesia (PCD). The mucosal samples obtained for cilia examination are generally procured from the nasal turbinate, but these specimens often yield inadequate results. The bronchial mucosa is recognized as an alternative sample, but no study has examined the additional utility of bronchial mucosa compared with nasal mucosa in the diagnosis of PCD.

Methods

The medical records of 96 patients who underwent TEM for suspected PCD between April 1997 and June 2017 were reviewed. Patients were divided into three groups based on the site of mucosal biopsy: nasal biopsy (NB) group with nasal mucosal biopsy only; bronchial biopsy (BB) group with bronchial mucosal biopsy only; and nasal and bronchial biopsy (NBB) group with a combination of nasal and bronchial mucosal biopsies.

Results

The rate of PCD diagnosis was 28.8% (17/59) in the NB group, 41.2% (7/17) in the BB group, and 60.0% (12/20) in the NBB group. The yield of PCD diagnosis significantly increased in the NBB group compared with the NB group (P=0.012). In the NBB group, 25.0% (5/20) of patients were diagnosed with PCD by nasal mucosal biopsy, and 35.0% (7/20) of patients were additionally diagnosed by bronchial mucosal biopsy. The presence of sinusitis or bronchiectasis was not associated with prediction of PCD diagnosis from nasal or bronchial mucosal biopsy.

Conclusions

The combination of nasal and bronchial mucosal biopsy for TEM showed higher yields of PCD diagnosis than nasal mucosal biopsy alone.

Persistent Wheeze in Infants: A Guide for General Pediatricians

Infants with persistent wheeze is a common diagnostic challenge for the general pediatrician because of the broad differential diagnoses. The initial diagnostic approach should include a comprehensive history, physical examination, and chest radiography. Additional testing may be warranted. Involvement of a pediatric pulmonary subspecialist may also be indicated. [Pediatr Ann. 2019;48(3):e110-e114.].

Accuracy of High-Speed Video Analysis to Diagnose Primary Ciliary Dyskinesia

BACKGROUND

Diagnosis of primary ciliary dyskinesia (PCD) relies on a combination of tests. High-speed video microscopy analysis (HSVA) is widely used to contribute to the diagnosis. It can be analyzed on the day of diagnostic consultation, but the qualitative analyses are subjective. Diagnostic accuracy and reliability of assessing ciliary function have not been robustly evaluated. We aimed to establish the accuracy of HSVA to diagnose PCD compared with a combination of tests, and to assess the interobserver reliability of HSVA analysis.

METHODS

We randomly selected and anonymized archived videos from 120 patients seen at three UK PCD centers. Three experienced scientists independently reviewed six videos per patient, using a standardized proforma, blinded to diagnostic and clinical data. We compared study outcomes with two references: (1) a combination of diagnostic tests in accordance with the European Respiratory Society PCD diagnostic guidelines and (2) original clinical outcome determined by all available diagnostic tests.

RESULTS

HSVA had excellent sensitivity and specificity to diagnose PCD: (1) 100% and 96%, respectively, compared with ERS guidelines, and (2) 96% and 91% compared with diagnostic outcomes. There was high interobserver agreement for "PCD-positive" outcomes (κ = 0.7).

CONCLUSIONS

Specialist scientists accurately diagnosed PCD using HSVA, with high interobserver agreement. HSVA can be reliably used to counsel patients and commence treatment on the day of testing while awaiting confirmatory investigations.

Proof of Concept: Very Rapid Tidal Breathing Nasal Nitric Oxide Sampling Discriminates Primary Ciliary Dyskinesia from Healthy Subjects

INTRODUCTION

Nasal nitric oxide (nNO) is extremely low in individuals with primary ciliary dyskinesia (PCD) and is recommended as part of early workup. We investigated whether tidal breathing sampling for a few seconds was as discriminative between PCD and healthy controls (HC) as conventional tidal breathing sampling (cTB-nNO) for 20-30 s.

METHODS

We performed very rapid sampling of tidal breathing (vrTB-nNO) for 2, 4 and 6 s, respectively. Vacuum sampling with applied negative pressure (vrTB-nNO_vac; negative pressure was applied by pinching the sampling tube) for < 2 s resulted in enhanced suction of nasal air during measurement. Feasibility, success rate, discriminatory capacity, repeatability and agreement were assessed for all four sampling modalities.

RESULTS

We included 13 patients with PCD, median (IQR) age of 21.8 (12.2-27.7) years and 17 HC, 25.3 (14.5-33.4) years. Measurements were highly feasible (96.7% success rate). Measured NO values with vrTB-nNO modalities differed significantly from TB-nNO measurements (HC: p < 0.001, PCD: p < 0.05). All modalities showed excellent discrimination. The vacuum method gave remarkably high values of nNO in both groups (1865 vs. 86 ppb), but retained excellent discrimination. vrTB-nNO_4sec, vrTB-nNO_6sec and vrTB-nNO_vac showed identical specificity to cTB-nNO (all: 1.0, 95% CI 0.77-1.0).

CONCLUSION

vrTB-nNO sampling requires only a few seconds of probe-in-nose time, is feasible, and provides excellent discrimination between PCD and HC. Rapid TB-nNO sampling needs standardisation and further investigations in infants, young children and patients referred for PCD workup.

Primary ciliary dyskinesia among Arabs: Where do we go from here?

Primary ciliary dyskinesia (PCD), also known as immotile-cilia syndrome, is a rare genetic disease that is inherited in an autosomal recessive manner. Several studies have explored certain aspects of PCD in the Arab world, yet much is still lacking in terms of identifying the different characteristics of this disease. In this paper, we aim to briefly cover those studies published about PCD in Arab countries, as well as to provide recommendations and guidelines for future studies.

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

Host Variability in NTM Disease: Implications for Research Needs

Non-tuberculous mycobacteria (NTM) are ubiquitous environmental organisms that may cause opportunistic infections in susceptible hosts. Lung infections in immunocompetent persons with structural lung disease are most common, while disseminated disease occurs primarily in immunocompromised individuals. Human disease caused by certain species, such as Mycobacterium avium complex, Mycobacterium abscessus, and Mycobacterium kansasii, is increasing in incidence and varies by geographic distribution. The spectrum of NTM disease varies widely in presentation and clinical outcome, but certain patterns can be organized into clinical phenotypes. Treatment options are limited, lengthy, and often toxic. The purpose of this case-based review is to provide non-clinician scientists with a better understanding of human NTM disease with an aim to stimulate more research and development.

Aerodigestive Approach to Chronic Cough in Children

Purpose of review

Chronic cough is the most common presenting complaint in a pediatric aerodigestive clinic. The etiology of chronic cough is varied and often includes more than one organ system. This review aims to summarize the current literature for a multidisciplinary approach when evaluating a child with chronic cough.

Recent findings

There is very little medical literature focused on a multidisciplinary approach to chronic cough. In the limited data available, multidisciplinary clinics have been shown to be more cost-efficient for the families of children with complex medical problems, and also increase the likelihood of successfully obtaining a diagnosis.

Summary

There is no consensus in the literature on how to work-up a child with chronic cough presenting to an aerodigestive clinic. Current studies from these clinics have shown improved outcomes related to cost-effectiveness and identifying definitive diagnoses. Future studies evaluating clinical outcomes are necessary to help delineate the utility of testing routinely performed, and to demonstrate the impact of interventions from each specialty on quality of life and specific functional outcome measures.