Developmental aspects of lung disease

Question 1

What are the 5 stages of lung growth and when do they occur?

Answer 1

Embryonic (3-8), pseudo-glandular (5-17), canalicular (16-26), saccular (24-38) and alveolar (38 weeks-8 years).

Question 2

At which stage does life become possible?

Answer 2

Towards the end of the canalicular phase as capillaries etc develop. Blood vessels are now very close to the airways and the air-blood barrier is formed.

Question 3

Which processes occur during the embryonic and pseudoglandular phases?

Answer 3

Formation of major airways, formation of bronchial tree and portions of respiratory parenchyma, and birth of the acinus.

Question 4

At which stage does surfactant become detectable in amniotic fluid?

Answer 4

Saccular phase - production starts at 25 weeks.

Question 5

What affects do abnormalities in the embryonic phase have?

Answer 5

Major structural abnormalities, airway narrowing and tracheo-oesophageal fistula.

Question 6

What affects do abnormalities in the pseudoglandular phase have?

Answer 6

Pulmonary sequestration (piece of lung tissue that sits outside the lung) and cyst formation.

Question 7

When does the diaphragm form?

Answer 7

At the end of the pseudoglandular phase. Closure occurs around 18 weeks.

Question 8

What is transient tachypnea?

Answer 8

Baby doesn’t clear fluid from lungs fast enough when it takes first breaths.

Question 9

What is hyaline membrane disease (IRDS)?

Answer 9

A surfactant deficiency. Antenatal glucocorticoids should be given to mother, or surfactant replacement if baby has already been born.

Question 10

What is chronic neonatal lung disease?

Answer 10

Fibrous tissue is laid down - this is largely irreversible. Children are more likely to have COPD in later life and increased severity bronchiolitis.

Question 11

List antenatal factors that may influence adult lung disease development.

Answer 11

In utero nicotine exposure, nutrition, low birth weight, micronutrients and vitamins. May get an older adult lung disease at an earlierage than you would normally, mainly due to damage during the alveolar phase.

Question 12

List postnatal factors that may influence adult lung disease development.

Answer 12

Infection, growth, tobacco exposure, pollution, micronutrients and vitamins.

Question 13

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

Answer 13

COPD. Low lung function in early life increases risk of future COPD.

Question 14

What happens if a person stops smoking?

Answer 14

Still have a deficit, but lung function can go back to normal decline.