developmental aspects of lung disease

Question 1

5 stages of lung development

Answer 1

embryonic, pseudoglandular, canalicular, saccular, alveolar

Question 2

between what age is embryonic lung development

Answer 2

3-8wks

Question 3

between what age is pseudoglandular lung development

Answer 3

5-17wks

Question 4

between what age is canalicular lung development

Answer 4

16-26wks

Question 5

between what age is saccular lung development

Answer 5

24-38wks

Question 6

between what age is alveolar lung development

Answer 6

36wks-2/3yrs

Question 7

embryonic lung development

Answer 7

lungs appear as offshoot from the oesophagus no clear cell differentiation yet ridge develops between oesophagus and trachea, lung buds continue to develop off, lobes can be seen developing

Question 8

pseudoglandular lung development

Answer 8

progressive spreading of the bronchi, conducting system begins to form as sections of the lung begin to divide off cilia develop around wk 13

Question 9

canalicular lung development

Answer 9

early gas exchange structures form lung becomes increasingly vascularised which is important in its overall development type I and II pneumocytes begin to differentiate structures involved in surfactant production are produced

Question 10

saccular lung development

Answer 10

further evolution of the gas exchange structures type I and II pneumocytes become visible thinning out of areas for gas exchange

Question 11

alveolar lung development

Answer 11

usually occurs after the child is born sacuoles change in shape, geometry and function after birth and continue to grow over the next 3-12 yrs

Question 12

post-natal lung growth

Answer 12

alveolar septation continues 100-150mln at birth to 200-600mln at 3-8yrs increased alveolar dimensions thereafter anything that affects the amount of alveoli you have in early life will have a knock on effect later on

Question 13

common upper (tracheo-bronchial) congenital abnormalities

Answer 13

tracheal agenesis and stenosis tracheomalacia tracheo-oesophageal fistula (relatively common)

Question 14

common lower (broncho-pulmonary) congenital abnormalities

Answer 14

lung agenesis/pulmonary hypoplasia bronchogenic cyst, CPAM (sporadic malformations) congenital diaphragmatic hernia

Question 15

how are congenital abnormalities diagnosed

Answer 15

antenatally newborn childhood asymptomatic - incidental finding

Question 16

presenting features antenatally

Answer 16

US scan 12 wk dating scan - abnormalities are more likely to be picked up at 20wks fluid amount can indicate problems w/ lungs or gut can do MRI to look for specific problems

Question 17

newborn presenting features

Answer 17

tachypnoea respiratory distress feeding issues - e.g. can’t breathe and feed at the same time

Question 18

childhood presenting features

Answer 18

recurrent symptoms stridor/wheeze (wheeze is usually monophonic) recurrent pneumonia (structural abnormality predisposes them) cough feeding issues

Question 19

how would CPAM appear on fetal imaging

Answer 19

white as it is often a cystic abnormality

Question 20

tracheal agenesis

Answer 20

very rare presents at birth with acute respiratory distress and inability to intubate usually diagnosed before birth

Question 21

tracheal stenosis

Answer 21

very rare complete cartilage rings - may be generalised or segmental present at birth or within first year 3 types, increasing narrowing of trachea, funnelling can create blockages

Question 22

tracheomalacia

Answer 22

more common floppiness of the airway dynamic abnormal collapse of tracheal walls closes readily during expiration, can be a problem during infection C shaped appearance in the back wall can be isolated in healthy infants

Question 23

what is tracheomalacia caused by

Answer 23

associated with genetic conditions may be caused by external compression e.g. vessels, tumour

Question 24

tracheomalacia presentation

Answer 24

barking cough recurrent croup SOB on exertion stridor/wheeze noisy in their regular breathing

Question 25

tracheomalacia manageent

Answer 25

physio and antibiotics when unwell natural history resolution with time SALBUTAMOL MAKES TRACHEOMALACIA WORSE

Question 26

tracheo-oesophageal fistula

Answer 26

abnormal connection between trachea and oesophagus association with genetic conditions primarily a GI problem but does affect both systems EA with distal TEF is most common

Question 27

how can tracheo-oesophageal fistula be diagnosed

Answer 27

antenatally (lots of fluid around baby) postnatally

Question 28

tracheo-oesophageal fistula presentation

Answer 28

choking colour change cough w/ feeding unable to pass NG tube

Question 29

tracheo-oesophageal treatment

Answer 29

surgical repair end to end anastamosis sometimes elongation is required depending on the severity of the condition

Question 30

tracheo-oesophageal fistula complications

Answer 30

tracheomalacia strictures leak reflux complications can still occur following repair

Question 31

congential pulmonary airway malformation (CPAM)

Answer 31

slightly more common abnormal non-functioning lung tissue can be cystic, vascular or trapped air in the non-functioning area 80% detected antenatally occur sporadically

Question 32

CPAM management

Answer 32

may resolve spontaneously in utero conservative management if asymptomatic surgical intervention may be required if there are respiratory difficulties possible risk of malignant change

Question 33

diaphragm development

Answer 33

essential for respiration develops from multiple tissues around 7wks innervated by phrenic nerve closure by ~18wks

Question 34

congenital diaphragmatic hernia

Answer 34

failure of closure 1/2500 births most common type is Bochdalek (90%) usually L side \> R side organs from abdominal cavity move up into the chest compress lungs and heart, lung can remain small depending on the stage of development

Question 35

how are congenital diaphragmatic hernias diagnosed

Answer 35

mostly antenatally some cases are diagnosed later

Question 36

how are congenital diaphragmatic hernias managed

Answer 36

surgical repair prognosis depends on the degree of lung hypoplasia and the side affected

Question 37

eventration of diaphragm

Answer 37

incidental finding diaphragm is formed but is a bit thinner pulling up occurs unequal on either side

Question 38

changes in the lungs after birth

Answer 38

lungs inflate fluid in the lungs is absorbed

Question 39

transient tachypnoea of newborn

Answer 39

associated w/ C section improves with 1-2 days lungs aren't squeezed s they come out the birth canal fluid isn't absorbed as quickly and persists for a couple of days wet patchy appearance on the CXR indicates fluid

Question 40

what is surfactant made up from

Answer 40

complx mix of phospholipids and lipophillic proteins

Question 41

when do type II pneumocytes differentiate

Answer 41

24-24wks

Question 42

neonatal lung disease

Answer 42

24-34 wks but can happen in any pre-term infant up to 37-38 wks respiratory distress syndrome occurs in preterm infants with surfactant deficiency also called hyaline membrane disease underexpanded lungs on CXR, patchy apperance

Question 43

treatment for neonatal lung disease

Answer 43

antenatal steroids to help mature baby's lungs surfactant replacement appropriate ventilation and nutrition

Question 44

complications of neonatal lung disease

Answer 44

chronic lung disease associated w/ prematurity where ongoing oxygen requirement at term also called bronchopulmonary dysplasia multifactorial causes - lungs being ventilated w/ too much pressure, sepsis etc associated with increased childhood respiraoty morbidity future COPD?

Question 45

relationship between fetal/paediatric and adult lung disease

Answer 45

antenatal - nicotine exposure, infection, maternal nutrition (micronutrients and vitamins), low birth weight, prematurity, antenatal steroids post-natal - Barker hypothesis, infection, growth during childhood (corresponds w/ lung function), tobacco exposure, environemental pollution, micronutrients/vitamins

Question 46

what is remodelling?

Answer 46

the airway doesn't stay static from birth but changes over time alteration of airway structure following external influence causes interference of inter-cellular signalling can perpetuate a cycle of chronic inflammation which damages the airway

Question 47

external influences on airway structure

Answer 47

environmental exposures chronic diseases of childhood infection

Question 48

remodelling - asthma

Answer 48

chronic inflammation increased bronchial responsiveness increase mucus secretion airway oedema airway narrowing

Question 49

remodelling - chronic lung disease

Answer 49

chronic inflammation interference in inter-cellular signalling treatment toxicity

Question 50

impact of early lung function into adulthood

Answer 50

lung function at birth and during childhood affects future resp health children born prematurely, peak at the same age but at a lower level then lung function decreases with age