Respiratory: Chronic Lung Disease of Prematurity; Primary Ciliary Dyskinesia Flashcards
Chronic lung disease of prematurity (CLDP) is also known as []
Chronic lung disease of prematurity (CLDP) is also known as bronchopulmonary dysplasia.
When does CLDP usually occur? [1]
How is a dx made [1] and at what age? [1]
It occurs in premature babies, typically those born before 28 weeks gestation. These babies suffer with respiratory distress syndrome and require oxygen therapy or intubation and ventilation at birth.
Diagnosis is made based on chest xray changes and when the infant requires oxygen therapy after they reach 36 weeks gestational age.
Describe the features of CLDP [5]
Low oxygen saturations
Increased work of breathing
Poor feeding and weight gain
Crackles and wheezes on chest auscultation
Increased susceptibility to infection
How can you prevent CLDP:
- pre-birth [1]
- post-birth [3]
There are several measure that can be taken to minimise the risk of CLDP. Giving corticosteroids (e.g. betamethasone) to mothers that show signs of premature labour at less than 36 weeks gestation can help speed up the development of the fetal lungs before birth and reduce the risk of CLDP.
Once the neonate is born the risk of CLDP can be reduced by:
* Using CPAP rather than intubation and ventilation when possible
* Using caffeine to stimulate the respiratory effort
* Not over-oxygenating with supplementary oxygen
Describe the long term management of CLDP [2]
Babies with CLDP require protection against respiratory syncytial virus (RSV) to reduce the risk and severity of bronchiolitis.
- This involves monthly injections of a monoclonal antibody against the virus called palivizumab. This is very expensive (around £500 per injection) so is reserved for babies meeting certain criteria.
- Babies may be discharged from the neonatal unit on a low dose of oxygen to continue at home, for example 0.01 litres per minute via nasal cannula. They are followed up to wean the oxygen level over the first year of life.
You perform a chest x-ray and find a patient to have dextrocardia and bronchiectasis.
What is the most likely pathology? [1]
Name two further signs of this pathology [2]
Kartagener syndrome (aka primary ciliary dyskinesia):
- dextrocardia
- bronchiectasis
- recurrent sinisitis
- subfertility
Describe the pathophysiology of PCD [5]
It is an autosomal recessive condition affecting the cilia of various cells in the body
- PCD causes dysfunction of the motile cilia around the body, most notably in the respiratory tract
- This leads to a buildup of mucus in the lungs, providing a great site for infection that is not easily cleared.
- This leads to a similar respiratory presentation to cystic fibrosis, with frequent and chronic chest infections, poor growth and bronchiectasis
- It also affects the cilia in the fallopian tubes of women and the tails (flagella) of the sperm in men, leading to reduced or absent fertility.
Kartagner’s triad describes the three key features of PCD. Not all patients will have all three features. These are:
- Paranasal sinusitis
- Bronchiectasis
- Situs Inversus
Describe the clinical significance of sinitus invertus [1]
Situs inversus on its own does not cause any problems, and patients can expect to live a normal life. A small number have associated congenital heart disease, such as transposition of the great arteries.
NB: Dextrocardia is when only the heart is reversed.
Describe the dx of PCD [3]
Patients typically present with recurrent respiratory tract infections. Take a careful family history and a history of consanguinity in the parents.
Examination and imaging (e.g. chest xray) can be used to diagnose situs inversus. Semen analysis can be used to investigate for male infertility.
The key investigation for establishing the diagnosis is to take a sample of the ciliated epithelium of the upper airway and examine the action of the cilia. A sample can be obtained through nasal brushing or bronchoscopy. Often several samples are required.
What questions do you need to ask about the parents of a patient with PCD ? [1]
It is more common in populations where there is consanguinity, meaning the parents are related to each-other. Consanguinity increases the risk of a child having two copies of the same recessive genetic mutation.
