Definition
Primary ciliary dyskinesia (PCD) is a rare, autosomal recessive disease of abnormalities of ciliary structure and function. The result is impaired mucociliary clearance, causing a variety of respiratory symptoms, and likely progression to bronchiectasis in most cases. Situs anomalies are present in nearly 50% of cases.
Prevalence
The prevalence of PCD is thought to be around l in 10,000-15,000, but is very difficult to estimate accurately. This is due partly to difficulties in making the diagnosis, as a consequence of the large variation in clinical phenotype.
Clinical manifestations
Children with PCD often have a clinical history oflower airway disease, manifested in a chronic wet-sounding cough and, occasionally, wheeze or shortness of breath. In addition, virtually all subjects show evidence of chronic upper airway symptoms, such as chronic rhinitis (nasal discharge, episodic facial pain and anosmia). Ear symptoms (recurrent otitis media and glue ear) are a frequent complication that can require repeated courses of antibiotics. In table 1, the clinical aspects of PCD are displayed by various age groups. PCD is likely to include a small number of milder phenotypes that may be manifest in subtle or no apparent structural defects and ciliary dysfunction small number of milder phenotypes that may be manifest in subtle or no apparent structural defects and ciliary dysfunction
Symptoms and findings of PCD according to age group
Diagnosis
The diagnosis of PCD requires the presence of the characteristic clinical phenotype and either specific ultra structural ciliary defects identified by transmission electron microscopy or evidence of abnormal ciliary function. Screening tests (nasal nitric oxide measurement, saccarin test) may precede formal ciliary function analysis, thereby reducing the number of referrals for ciliary analysis. A positive family history of PCD is an indication for performing diagnostics. Siblings of probands should also have PCD excluded.
Several genes have been identified to date for autosomal recessive PCD variants. Genetic analyses may help to assess the carrier status of family members and provide tools for informed reproductive choices, although this is currently possible only for a minority of families. They may also become more important diagnostically since about 35% of PCD patients carry gene mutations.
Referral
Diagnosis should be confirmed in a specialist centre, as diagnostic analysis and interpretation are difficult.
Treatment and follow-up
As with all chronic respiratory diseases, the aim of therapy for PCD is to restore or maintain normal lung function as far as is possible, based on early detection and vigorous treatment of complications.Management of PCD involves aggressive treatment of upper and lower airway infections by antibiotics, and airway clearance by combinations of physiotherapy and physical exercise.
By analogy with cystic fibrosis (CF), PCD patients should be managed in specialised centres, in which they have regular access to respiratory paediatricians, audiology, ENT surgeons and respiratory physiotherapists.
Key messages
Presentation in PCD is often non-specific, or has features typical of many childhood illnesses
Think about PCD if your patient has chronic symptoms of both upper and lower airway infection and situs inversus viscerum
PCD is an important cause of progressive lung disease and our key aim is to establish an early diagnosis and institute treatment strategies prior to the onset of irreversible lung damage.
Refer the patient to a centre with experience in performing ultrastructural and functional studies of cilia
Follow your patient in collaboration with the reference centre
Case report
A 7-year-old boy was referred to a paediatric outpatient clinic for asthma resistant to treatment. He had a history of nasal obstruction with chronic mucopurulent discharge and chronic cough since the first months of life. He also presented with recurrent episodes of otitis media with secretion during infancy and two episodes of pneumonia during his preschool years. No overt episodes of wheezing were described. At the age of 6 years, a skin prick test showed positivity to house dust mites and alternaria. The diagnosis of allergic rhinitis and asthma was made, and treatment with inhaled corticosteroids and antihistamines was given for months, with no success.
At physical examination, situs inversus viscerum with dextrocardia was revealed. Spirometry was normal. Electron microscopy revealed ultrastructural ciliary defects in 100% of cilia obtained by nasal brushing. The diagnosis of primary cilia dyskinesia was made and proper management was planned.
- ©ERS 2015
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