Developmental Aspects of Lung Disease Flashcards
What are the 5 stages of the lung morphogenesis?
- Embryonic
- Pseudo-glandular
- Canalicular
- Saccular
- Alveolar
What occurs in the embryonic stage?
Appearance of lung buds and main pulmonary arteries
Trachea and main bronchi
What occurs in the pseudo glandular stage?
All conducting airways and accompanying blood vessels form
What occurs in the canicular stage?
Respiratory airways form
Blood gas barrier thins - cuboidal to squamous
Alveolar ducts
What occurs in the saccular stage?
Surfactant becomes produced
Saccules and alveoli appear
What occurs in the alveoli stage?
Alveoli multiply
Airways double in size
What 4 developmental problems can occur in early stages?
Airway stenosis
Airway malacia
Pulmonary genesis/hypoplasia
Tracheo-oesophageal fistula
What developmental problems can occur in early stages?
Bronchogenic cyst
Congenital pulmonary anomalies: lobar emphysema, crystadenomatoid malformation, sequestration
How are do abnormalities present in foetus’?
Through ultrasound
How do abnomalities present in foetus’?
Tachypnoea Respiratory distress (chest wall retraction)
How do abnormalities present childhood?
Stridor/wheeze
Recurrent pneumonia
Incidental finding
What are common congenital lung disease?
Tracheo-bronchomalacia
What are the presentation of tracheo-bronchomalacia?
Barking cough
Early onset/recurrent croup
SOBOE
Stridor/wheeze
What is the management for tracheo-broncomalacia?
Airway clearance
Antibiotics
Avoid asthma treatment
Natural history resolution with time
What is the management for pulmonary adenomatoid malformation?
May resolve spontaneously un uteroo
Conservative management id asymptomatic
There is risk of malignant change
What are problems that can occur with diaphragmatic abnormalities?
Diaphragmatic hernia (bowel migrated up into the chest) Eventration
What can cause diaphragmatic hernia?
Pulmonary hypoplasia
Persistent pulmonary hypertension
What is eventration?
When diaphragm muscles doesn’t form properly and become weak, forming a bulge and not contracting on inspiration - can protrude up into the thorax
What are functional changes at birth?
Change from fluid secretion to fluid absorption:
Transient tachypnoea of newborn as amniotic fluid remains in lung after birth - resolves in 24-48hrs
Give an example of neonatal lung disease and what is the treatment?
Surfactant deficiency: Hyaline Membrane Disease (RDS)
Treatment:
Antenatal glucocorticoids
Surfactant replacement
Suportive
Endogenous surfactant production by day 5
What is chronic neonatal lung disease
A very severe bronchiolitis leads to alveolar damage, inflammation and scarring (reduced compliance)
Increased childhood respiratory morbidity
Also called: bronchopulmonary dysplasia, CLD prematurity
What is the cause of chronic neonatal lung disease?
Antenatal infection
Barotrauma/oxygen toxicity
PDA
Genetic
What antenatal features can occur that increase risk of developing COPD?
Nicotine Fetal infection Maternal nutrition Low birth weight/prematurity (antenatal steroids) Maternal vitamins
What postnatal problems can occur that increase the risk of developing COPD?
Infection Growth (poor then more prone to resp disease) ETS (+/- a1 AT deficiency) Pollution Vitamins
Explain the influences on lung development with regards to the tracking of pulmonary function
Normal childhood growth/accelerated decline
Normal childhood growth/early decline
Failure to attain maximal growth/normal decline
Failure to attain maximal growth/abnormal decline
What is remodelling?
Alteration of structure following an external influence
What is the effect of prenatal nicotine exposure in terms of remodelling?
Lung hypoplasia
Reduced alveolarisation
Reduced lung function (small airways)
Increased susceptibility to infection
What remodelling occurs in asthma?
Chronic inflammation: Increased bronchial responsiveness Increase mucus secretion Airway oedema Airway narrowing
