Developmental Aspects of Lung Disease

Question 1

What are the 5 stages of the lung morphogenesis?

Answer 1

1. Embryonic
2. Pseudo-glandular
3. Canalicular
4. Saccular
5. Alveolar

Question 2

What occurs in the embryonic stage?

Answer 2

Appearance of lung buds and main pulmonary arteries

Trachea and main bronchi

Question 3

What occurs in the pseudo glandular stage?

Answer 3

All conducting airways and accompanying blood vessels form

Question 4

What occurs in the canicular stage?

Answer 4

Respiratory airways form
Blood gas barrier thins - cuboidal to squamous
Alveolar ducts

Question 5

What occurs in the saccular stage?

Answer 5

Surfactant becomes produced

Saccules and alveoli appear

Question 6

What occurs in the alveoli stage?

Answer 6

Alveoli multiply

Airways double in size

Question 7

What 4 developmental problems can occur in early stages?

Answer 7

Airway stenosis
Airway malacia
Pulmonary genesis/hypoplasia
Tracheo-oesophageal fistula

Question 8

What developmental problems can occur in early stages?

Answer 8

Bronchogenic cyst

Congenital pulmonary anomalies: lobar emphysema, crystadenomatoid malformation, sequestration

Question 9

How are do abnormalities present in foetus’?

Answer 9

Through ultrasound

Question 10

How do abnomalities present in foetus’?

Answer 10

Tachypnoea 
Respiratory distress (chest wall retraction)

Question 11

How do abnormalities present childhood?

Answer 11

Stridor/wheeze
Recurrent pneumonia
Incidental finding

Question 12

What are common congenital lung disease?

Answer 12

Tracheo-bronchomalacia

Question 13

What are the presentation of tracheo-bronchomalacia?

Answer 13

Barking cough
Early onset/recurrent croup
SOBOE
Stridor/wheeze

Question 14

What is the management for tracheo-broncomalacia?

Answer 14

Airway clearance
Antibiotics
Avoid asthma treatment
Natural history resolution with time

Question 15

What is the management for pulmonary adenomatoid malformation?

Answer 15

May resolve spontaneously un uteroo
Conservative management id asymptomatic
There is risk of malignant change

Question 16

What are problems that can occur with diaphragmatic abnormalities?

Answer 16

Diaphragmatic hernia (bowel migrated up into the chest)
Eventration

Question 17

What can cause diaphragmatic hernia?

Answer 17

Pulmonary hypoplasia

Persistent pulmonary hypertension

Question 18

What is eventration?

Answer 18

When diaphragm muscles doesn’t form properly and become weak, forming a bulge and not contracting on inspiration - can protrude up into the thorax

Question 19

What are functional changes at birth?

Answer 19

Change from fluid secretion to fluid absorption:

Transient tachypnoea of newborn as amniotic fluid remains in lung after birth - resolves in 24-48hrs

Question 20

Give an example of neonatal lung disease and what is the treatment?

Answer 20

Surfactant deficiency: Hyaline Membrane Disease (RDS)

Treatment:
Antenatal glucocorticoids
Surfactant replacement
Suportive

Endogenous surfactant production by day 5

Question 21

What is chronic neonatal lung disease

Answer 21

A very severe bronchiolitis leads to alveolar damage, inflammation and scarring (reduced compliance)

Increased childhood respiratory morbidity

Also called: bronchopulmonary dysplasia, CLD prematurity

Question 22

What is the cause of chronic neonatal lung disease?

Answer 22

Antenatal infection
Barotrauma/oxygen toxicity
PDA
Genetic

Question 23

What antenatal features can occur that increase risk of developing COPD?

Answer 23

Nicotine 
Fetal infection 
Maternal nutrition 
Low birth weight/prematurity (antenatal steroids)
Maternal vitamins

Question 24

What postnatal problems can occur that increase the risk of developing COPD?

Answer 24

Infection 
Growth (poor then more prone to resp disease)
ETS (+/- a1 AT deficiency)
Pollution 
Vitamins

Question 25

Explain the influences on lung development with regards to the tracking of pulmonary function

Answer 25

Normal childhood growth/accelerated decline
Normal childhood growth/early decline
Failure to attain maximal growth/normal decline
Failure to attain maximal growth/abnormal decline

Question 26

What is remodelling?

Answer 26

Alteration of structure following an external influence

Question 27

What is the effect of prenatal nicotine exposure in terms of remodelling?

Answer 27

Lung hypoplasia
Reduced alveolarisation
Reduced lung function (small airways)
Increased susceptibility to infection

Question 28

What remodelling occurs in asthma?

Answer 28

Chronic inflammation:
Increased bronchial responsiveness 
Increase mucus secretion 
Airway oedema 
Airway narrowing