Developmental Aspects of Lung Disease Flashcards
What are the 5 stages of structural lung development and when do they occur?
- embryonic 3-8 weeks
- Pseudo-glandular 5-17 weeks
- Canalicular 16-26 weeks
- Saccular 24-38 weeks
- 24-38 weeks
- Alveolar 36 weeks-2/3 years
What embryonic structure does the lung bud originate from?
Foetal foregut
What embryonic structure do the blood vessels and connective tissues surrounding he lungs originate from?
Mesoderm
In what stage of foetal lung development does rapid branching occur?
Pseudoglandular
In what stage of embryonic lung development do specialised cells such as cilia and mucous glands develop?
Pseudoglandular
In which stage of embryonic lung development do terminal bronchioles, alveolar sacs and capillary blood vessels form gas exchange units.
Canalicular
In which stage of embryonic lung development do type 1 and type 2 pneumocytes appear.
Canalicular
What happens in the saccular phase of lung development?
alveolar sacs grow in size and become well formed
More surfactant is produced in this stage & the bronchioles will continue to elongate.
The interstitial tissue between the sacs begins to reduce and the alveolar walls become thinner
During which stage are the lungs able to independently sustain breathing?
Alveolar phase
How many alveolar air sacs does an infant have at birth?
20-60 million
How many alveolar air sacs does a child have by the time the they reach school age?
200-300 million
What is Laryngomalacia?
Congenital abnormal collapse of the larynx or voice box
How does Laryngomalacia present?
stridor or inspiratory squeak which worse when the baby is active, emotional or feeding
How is Laryngomalacia managed?
It generally improves so watch and wait. Intervention is only when the baby is struggling to feed, breath or is failing to thrive
What is tracheomalacia?
dynamic abnormal collapse of tracheal walls
How does tracheomalacia present?
- Barking cough
- Recurrent “croup”
- Breathless on exertion
- Stridor/wheeze
What are the common causes of tracheomalacia?
genetic conditions
external compression (e.g. from a tumour)
How is tracheomalacia managed?
physio and antibiotics when unwell (the condition will remove with time)
What is a Tracheo-oesphageal fistula
an abnormal connection between the trachea and the oesophagus
How does a Tracheo-oesphageal fistula present in a newborn?
A choking colour change (due to the inability to clear secretions), coughing with feeding and an inability to pass a nasogastric tube into the stomach.
How is a Tracheo-oesphageal fistula managed?
It must be surgically repaired
What is a Congenital Pulmonary Airway Malformation?
abnormal non-functioning lung tissue
What % of Congenital Pulmonary Airway Malformation cases are detected antenatally?
80%
How should Congenital Pulmonary Airway Malformation be managed?
Conservative management should be applied if CPAM is asymptomatic
Surgical intervention may be required
What is the risk associated with Congenital Pulmonary Airway Malformation?
malignant change
At what stage of gestation does the diaphragm begin to form?
7 weeks gestation
At what stage of gestation does the diaphragm close?
by 18 weeks
How many live births are affected by congenital diaphragmatic hernia?
1 in 2500 births
What is the most common type of congenital diaphragmatic hernia?
Bochdalek
What side of the diaphragm is the most common for a congenital diaphragmatic hernia?
Left side
Is a left or right sided congenital diaphragmatic hernia associated with worse outcomes?
Right sided is associated with worse outcomes
What is the prognosis of congenital diaphragmatic hernia associated with?
Prognosis depends on degree of lung hypoplasia
How is congenital diaphragmatic hernia managed?
surgically
What is Transient Tachypnoea of the Newborn?
The amniotic fluid in the lungs does not move off as fast as it should have
What is Transient Tachypnoea of the Newborn associated with and why?
Caesarian section.
This occurs because the child has not passed through the birth canal and the first breath was not vigorous.
How is Transient Tachypnoea of the Newborn managed?
generally improves within 1-2 days but occasionally will require a degree of respiratory support or oxygen
What causes respiratory distress syndrome?
surfactant deficiency
What does respiratory distress syndrome look like on an x-ray?
Ground glass appearance
What are the three things that should be given in a case of respiratory distress syndrome?
- Antenatal steroids
- Surfactant replacement
- Appropriate ventilation and nutrition
What is chronic lung disease?
Chronic Lung Disease is associated with prematurity where ongoing oxygen support is required at term
What is lung remodelling?
Remodelling is the alteration of airway structure following external influences
Name three things that can cause remodelling
- Environmental exposures
- Chronic diseases of childhood
- Infection
