Developmental aspects of lung disease

Question 1

Names of stages of lung morphogenesis

Answer 1

embryonic
pseudo-glandular
canalicular
saccular 
alveolar

Question 2

at which stage of life can you survive due to your lungs being sufficiently developed

Answer 2

24-26 weeks

this is within the canalicular stage

Question 3

what happens in embryonic stage lung morphogenesis

Answer 3

tube forms from the top of the foetus to the bottom. This divides into right and left airways.
Primitive trachea and larynx formed

Question 4

what happens during canalicular?

Answer 4

last generations of the lung periphery formed epithelial differentiation- cells flatten/become squamous, air-blood barrier formed to allow for gas exchange.

Question 5

what happens in pseudo glandular stage

Answer 5

cartilage begins to form
major airways formed
lung lobes formed
no air sacs and no possibility of gas exchange yet though

Question 6

alveolar stage

Answer 6

smaller and smaller alveoli, improving surface area allowing for more gas exchange

Question 7

what happens in saccular stage

Answer 7

expansion of air spaces surfactant detectable in amniotic fluid

Question 8

what happens with lung growth in postnatal

Answer 8

the alveolar septation (division) continues into late childhood/early adulthood

Question 9

which stages does the umbrella term ‘organogenesis’ in lung development cover?

Answer 9

embryonic

pseudoglandular

Question 10

which stages does the umbrella term ‘differentiation’ in lung development cover?

Answer 10

canalicular
saccular
alveolar

Question 11

prediction of problems in lung development

Answer 11

you can predict problems/ type of problems depending on which stage it occurs at

Question 12

what is pulmonary sequestration

Answer 12

rare malformation (present from birth) where non-functioning lung tissue is separated from the rest of the lung and supplied with blood from an unusual source, often an artery from systemic circulation

Question 13

what problems can arise later on in lung development

Answer 13

bronchogenic cysts
solid tissues
sequestration
lobar emphysema- air can enter lung but can’t escape

Question 14

when are abnormal features presented?

Answer 14

75% in fetal ultrasound
10% in newborn
15% in childhood

Question 15

problems that present in a newborn

Answer 15

tachypnea - breathing fast

respiratory distress

Question 16

problems that present in childhood

Answer 16

stridor- noisy breathing- turbulent air flow
recurrent pneumonia
incidental finding

Question 17

when are the majority of lung problems picked up?

Answer 17

in foetal ultrasounds
NHS usually offers 2 scans during pregnancy
within 8-14 weeks and 18-21 weeks

Question 18

What are 2 common congenital lung diseases?

Answer 18

tracheo-bronchomalacia

pulmonary adenomatoid malformation

Question 19

symptoms of tracheo-bronchomalacia lung disease

Answer 19

barking/seal like cough
early onset/ recurrent croup
breathless on exertion
stridor/wheeze

Question 20

management of tracheo-bronchomalacia lung disease

Answer 20

Airway clearance physiotherapy

Antibiotics

Avoid “asthma” treatment (especially bronchodilators)

Question 21

symptoms of adenomatoid malformation describe + what is the management

Answer 21

may resolve in utero but possible risk of malignant change

if asymptomatic - leave the legions alone

Question 22

development of the diaphragm

Answer 22

a variety of embryonic/primitive tissue contributes to the diaphragm- they join up and become a fibrous band
it is complete by 18 weeks

Question 23

What is tracheal, laryngeal stenosis

Answer 23

narrowing of the airway

Question 24

what is pulmonary agenesis?

Answer 24

complete absence of the lung parenchyma, bronchus and lung vasculature

Question 25

what are diaphragmatic abnormalities?

Answer 25

Diaphragmatic hernia

Eventration

Question 26

describe diaphragmatic hernia

Answer 26

usually occurs on the left lung
pulmonary hypoplasia (underformation)
cystic looking lesion

Question 27

describe eventration

Answer 27

incomplete muscularisation of the diaphragm- area of floppiness, thin membrane

Question 28

functional changes in lung at birth

Answer 28

at birth there is a change from fluid secretion to fluid absorption hence why first few breaths are the hardest. Newborns need to push fluid out of their lungs

Question 29

what is ‘wet lung’

Answer 29

a name for tachypnea - fast breathing

a newborn might have a weak cry and fast, labored breathing. This is caused by extra amniotic fluid in the lungs (wasn’t able to push out as well as necessary)

Question 30

is wet lung resolvable?

Answer 30

it usually resolves in 24-48 hours

normally associated with casesarean section delivery

Question 31

what is surfactant

Answer 31

detergent like fluid that stabilises alveoli by reducing surface tension and preventing them from collapsing
it also promotes gas exchange

Question 32

which types of pneuomcytes produce surfactant

Answer 32

type 2

Question 33

what happens with surfactant production if you are born too early

Answer 33

you won’t have produced surfactant and so your alveoli are more likely to collapse

Question 34

what’s the treatment for surfactant deficiency?

Answer 34

Antenatal glucocorticoids
Surfactant replacement
Mechanical ventilation- noninvasive is CPAP (mask)

Question 35

why is it bad for a mother to smoke during pregnancy?

Answer 35

nicotine can cross the placenta barrier and will interfere with/ affect the development of prenatal airways

Question 36

define remodelling

Answer 36

alteration of structure following an external influence ie smoking

Question 37

pre-natal nicotine exposure can lead to what?

Answer 37

Lung hypoplasia (under development)

Reduced alveolarisation

Reduced lung function (small airways)

Increased incidence wheeze syndromes

Increased susceptibility to infection

Interference of inter-cellular signalling

Question 38

What is meant by respiratory parenchyma?

Answer 38

Pulmonary parenchyma is a term for lung tissue, including bronchioles, interstitium and alveoli