Developmental Aspects of Lung Disease

Question 1

What are the stages of lung morphogenesis?

Answer 1

Embryonic, Pseudo-glandular, Canalicular, Saccular, Alveolar

Question 2

When is extra-uterine life possible?

Answer 2

Later canalicular/early saccular stage (23-25 weeks)

Question 3

What occurs during Embryonic stage?

Answer 3

From the primitive gut (oesophagus) grows the trachea and larynx. Trachea starts to bud into the left and right airways.

Question 4

What happens during the pseudo-glandular stage?

Answer 4

Cartilage is beginning to form, major airways formed with the lobes. No air sacs at the end of the tubes so no gas exchange.

Question 5

What happens during the Canalicular stage?

Answer 5

Tubes are branching more and epithelia start to flatten and become thinner. Air-blood barrier formed. Vessels and capillaries closely aligned.

Question 6

What occurs during the Alveolar stage?

Answer 6

Septation (divide) occurring which improves the surface area to allow gas exchange to be sufficient.

Question 7

What happens during postnatal lung growth?

Answer 7

Alveolar separation continues, increased alveolar dimensions, increase in number of alveoli

Question 8

What happens during Saccular stage?

Answer 8

Expansion of airways, surfactant detectable in amnionic fluid.

Question 9

What stages are part of Organogenesis?

Answer 9

Embryonic and pseudo-glandular.

Question 10

When does surfactant production begin?

Answer 10

Surfactant production begins at 25 weeks

Question 11

What conditions are connect with an early on deformity of the lung?

Answer 11

Airway stenosis - narrowing
Airway Malacia - softening of the cartilage
Pulmonary agenesis - lung isn’t developed
Pulmonary hypoplasia

Question 12

What conditions occur as a result of mutation with a later onset?

Answer 12

Bronchogenic cyst
Congenital pulmonary abnormalities
Lobar emphysema - alveoli not well developed
cystadenomatoid malformation
Sequestration - look normal but not in traditional anatomy

Question 13

When do the presenting features occur?

Answer 13

Fetal ultrasound (75%)
Newborn (10%)
Childhood (15%)

Question 14

What conditions can be diagnosed in Newborn?

Answer 14

Tachypnea - fast breathing

Respiratory distress

Question 15

What conditions can be diagnosed in childhood?

Answer 15

Stridor/wheeze
Recurrent pneumonia (same region)

Question 16

What does a malformation look like in an ultrasound?

Answer 16

Lungs mainly filled with fluid which should appear white - abnormalities usually bit darker

Question 17

What do abnormalities look like in X-rays?

Answer 17

White patch filled with fluid.

Question 18

Describe Tracheo-bronchmalacia (weak cartilage rings).

Answer 18

Barking/seal like cough, Early onset, breathlessness on exertion, stridor/wheeze. Rely on smooth muscle to maintain airway - don’t use Bronchodilator.

Question 19

Describe Pulmonary Cystic Adenomatoid malformation.

Answer 19

May resolve spontaneously, Conservative management if asymptomatic, possible risk of malignant change.

Question 20

How is the diaphragm developed?

Answer 20

Variety primitive tissues contribute to it.

Question 21

Describe a diaphragm hernia.

Answer 21

Pulmonary hypolasion (underdeveloped), persistent pulmonary hypotension (high blood pressure)

Question 22

What is a diaphragm eventration?

Answer 22

Diaphragm is sitting higher up or rather than looking dome shaped its edges are sharper.

Question 23

What is an abnormality in the fluid capacity at birth?

Answer 23

Change from fluid secretion to fluid absorption. Normally the secreting organ becomes the absorbing one. In this case there is a slowing down of the functional change.

Question 24

What is the functional change in surfactant system?

Answer 24

Surfactant stabilises alveoli and promotes gas exchanage

Question 25

Describe Hyaline Membrane Disease (RDS)

Answer 25

Surfactant deficiency. Treated with surfactant replacement, Antenatal glucocorticoids.

Question 26

When does endogenous production begin if suffering with RDS?

Answer 26

5 days

Question 27

What are antenatal origins of adult lung disease?

Answer 27

In utero nicotine exposure, fetal infection, maternal nutrition, low birth weight, maternal micronutrients/vitamins

Question 28

What are the Post-natal origins of Adult lung disease?

Answer 28

Infection, growth, ETS, environmental pollution, micronutrients/vitamins

Question 29

what causes a rapid decline is FEV1 and at what age will they develop respiratory symptoms?

Answer 29

Smoking, symptoms at roughly 65-70 years.

Question 30

What is the definition of remodelling?

Answer 30

Alteration of structure following an external influence

Question 31

What does pre-natal nicotine exposure cause?

Answer 31

Lung hypoplasia, reduced alveolarisation, reduced lung function, increased wheeze, increased susceptibility to infection, interference of inter-cellular signalling

Question 32

What remodelling occurs in asthma?

Answer 32

Chronic inflammation, increased bronchial responsiveness, increased mucus secretion, airway oedema, airway narrowing.

Question 33

What remodelling occurs in chronic neonatal lung disease?

Answer 33

Chromic inflammation, interference of signalling, treatment toxicity. Mosaic appearance with different shades = collapsing alveoli

Question 34

What is the 3rd leading cause of death

Answer 34

COPD

Question 35

What causes the remodelling of airways?

Answer 35

Antenatal programming, environmental exposures and gene interactions

Question 36

How can we track development of COPD?

Answer 36

Low lung function and CT scans