Developmental aspects of lung disease

Question 1

What is the groove that the lungs develop from?

Answer 1

Sulcus laryngeotrachealis or the laryngeotracheal groove

Question 2

What buds from the laryngeotracheal groove?

Answer 2

Lung primordium

Question 3

Which pharyngeal arch artery pair forms the pulmonary circulation?

Answer 3

6th pharyngeal arch aortic artery

Question 4

What occurs in the canalicular stage that means the foetus is then able to live outside the uterus from around 24 weeks?

Answer 4

Differentiation of type II pneumocytes into flattened type I cells

Proliferation of capillaries into the mesenchyme

Question 5

How can we measure clinically the maturity of an foetus’ lungs?

Answer 5

Lungs are now producing a large amount of the amniotic fluid (surfactant) - the ratio of lecithin to sphingomyelin in the amniotic fluid increases with foetal age

Question 6

How long does alveolarisation continue after birth?

Answer 6

1 and half years after birth

Question 7

How many alveoli are in new borns?

Answer 7

100-150 million

Question 8

How many alveoli are there once you reach 3-8 years old?

Answer 8

200-600 million

Question 9

Name some congenital lung diseases that result from embryonic stage defects

Answer 9

Tracheal or laryngeal stenosis
Pulmonary agenesis
Trachea-oesophageal fistula/atresia
Diaphragmatic abnormalities - hernia, eventration

Question 10

When do the 4 components of the primitive diaphragm seal to form the mature diaphragm?

Answer 10

18 weeks

Question 11

Name some congenital lung diseases associated tie pseudo glandular stage defects

Answer 11

Pulmonary sequestration (intralobular/extralobular)

Cystadenomatoid malformation

Cyst formation

Question 12

What type of pulmonary sequestration is more common?

Answer 12

Intralobular, presents later on in childhood due to recurrent infections

Question 13

How does extra lobular pulmonary sequestration usually present?

Answer 13

Less common, seen in neonates. Cyanosis and respiratory distress

Question 14

Which side of the diaphragm is more likely to have a hernia?

Answer 14

Left - liver on right can act as a plug

Question 15

What are the major complications associated with diaphragmatic abnormalities?

Answer 15

Pulmonary hypoplasia

Persistent pulmonary hypertension

Question 16

What is the most common cause of respiratory distress in newborns?

Answer 16

Transient tachypnoea of the newborn

Question 17

List some causes of respiratory distress in newborns

Answer 17

Transient tachypnoea of the newborn
Surfactant deficiency - HMD
Chronic neonatal lung disease

Question 18

Describe transient tachypnoea of the newborn

Answer 18

Period of rapid breathing (>30-60/min) following birth, likely due to retained lung fluid which hasn’t been absorbed as fast by the pulmonary lymphatic system

Question 19

Describe some signs and symptoms of transient tachypnoea

Answer 19

Rapid breathing (>30-60/min)
Hyperinflated lungs (CXR)
Prominent pulmonary vascular markings (CXR)
Flattening of the diaphragm (CXR)
Fluid in horizontal fissure (CXR)

Question 20

How do you treat transient tachypnoea of the newborn?

Answer 20

Supplemental oxygen

Antibiotics

Question 21

What can induce transient tachypnoea of the newborn?

Answer 21

Caesarean section
Pulmonary immaturity
Surfactant deficiency

Question 22

What are the secretory organelles in type II pneumocytes which excrete surfactant?

Answer 22

Lamellar bodies

Question 23

How do you treat neonates with surfactant deficiency?

Answer 23

Antenatal glucocorticoids 
Surfactant replacement therapy
Oxygen
CPAP
Mechanical ventilation

Question 24

Why are glucocorticoids used in babies with surfactant deficiency?

Answer 24

Stimulates surfactant production

Question 25

How long does it take for glucocorticoids to take effect?

Answer 25

5 days

Question 26

When a baby is to be delivered early (e.g. emergency, pre-eclampsia), how can we prevent respiratory distress of the baby?

Answer 26

Glucocorticoids 5 days prior

Question 27

Describe chronic neonatal lung disease

Answer 27

Development of fibrous tissue due to chronic inflammation. Caused by genetics, infection etc.

Question 28

What are the possible long term effects of chronic neonatal lung disease?

Answer 28

Increased severity bronchiolitis
Causes asthma
Could lead to development of COPD later on

Question 29

What are some antenatal causes of adult long disease?

Answer 29

In utero nicotine exposure
Nutrition
Sex?
Low birth weight/prematurity
Micornutrients/vitamins

Question 30

What are some postnatal causes of adult long disease?

Answer 30

Infection
Growth
Environmental tobacco smoke
Environmental pollutants
Micronutrients/vitamins

Question 31

What is the 3rd leading cause of death in the world?

Answer 31

COPD