Developmental Aspects of Lung Disease Flashcards
What are the stages of lung morphogenesis?
Embryonic - 3-8 weeks
Pseudo-glandular - 5-17
Canalicular - 16 - 26
Saccular - 24 - 38
Alveolar - 36 weeks - 2/3 years
What happens during the embryonic and pseudoglandular stages of lung development?
Formation of :
Major Airways, Bronchial tree and portions of respiratory parenchyma, acinus
Embryonic: appearance of lung buds and main pulmonary arteries
Pseudoglandular: All conducting airways and accompanying blood vessels form
What is meant by respiratory parenchyma?
lung tissue, including bronchioles, interstitium and alveoli
What happens during the canalicular stage of lung development?
Last generations of the lung periphery formed
Epithelial differentiation - acinai are replacing columnar epithelium with squamous epithelium
Air-blood barrier formed
What is significant about the canaliculi stage?
Life outside of the uterus is possible after the canalicular stage
What happens during the saccular stage?
Expansion of air spaces
Surfactant detectable in amnionic fluid
What happens during the alveolar stage?
Secondary septation
Which stages are organogenesis
Which are differentiation?
Organogenesis (embryonic and pseudoglandular)
Differentiation (cannalicular and saccular)
What are the common congenital abnormalities
Upper
- Laryngomalacia and tracheomalacia
- Tracheo-oesphageal fistula
Lower
- CPAM
- Congenital Diaphragmatic Hernia
How are congenital abnormalities detected during antenatal scanning
US
MRI
How are congenital abnormalities detected in a newborn
- Tachypnoea
- Respiratory distress
- Feeding issues
How are congenital abnormalities detected in childhood
- stridor/wheeze
- recurrent pneumonia
- chronic cough
- feeding issues
Describe laryngomalacia
- softening of larynx
- infants > 6 w.
- stridor, worse on feeding/upset/excited
- improve within 1y
- concern if failure to thrive/apnoeas
Describe tracheomalacia
- healthy baby/genetic disease/external compression (tumour, vessel)
- barking cough, recurrent croup
- stridor wheeze
- SOB on exertion
- physio + Abx if unwell
- natural resolution
Describe Trachea-oesophageal fistula
- might have oesophageal atresia (abnormally closed passage)
- antenatal or postnatal diagnosis
What are the symptoms of Trachea-oesophageal fistula
- choking
- colour change
- cough w/feeding
- unable to pass NG tube
- can cause tracheomalacia, strictures, leak, reflux
Surgical repair
Describe Congenital pulmonary airway malformation (CPAM)
- abnormal non-functioning tissue
- mostly antenatally
- sporadic
- resolve in utero
- conservative management if asymptomatic
- surgery
- risk of cancer
Describe Congenital diaphragmatic hernia
- diaphragm develops 7-18 w.
- hernia= improper closure of diaphragm
- left side> right side
- BUT right side WORSE
- antenatal diagnosis
- surgery
- prognosis depends on lung hypoplasia
How is the diaphragm formed?
Various sheets of primitive tissue move towards the centre of the diaphragm.
What are the outcomes of diaphragmatic hernia?
Pulmonary hypoplasia
Persistant pulmonary hypertension
What are the functional changes in the lung at birth?
Change from fluid secretion to fluid absorption
Pulmonary vasodilation
What is Transient tachypnea of the Newborn?
- C-section= fluid in lungs
- Resolves in 1-2 d
Describe respiratory distress syndrome
- Surfactant deficiency
- Antenatal steroids
- Surfactant replacement
- Ventilation
Describe bronco-pulmonary dysplasia
- Premature
- Need O2 therapy
- ↑ risk of resp disease
