Developmental aspects of lung disease Flashcards
what are the 5 stages in lung morphogenesis?
- embryonic
- pseudo-glandular
- canalicular
- saccular
- alveolar
when is extra-uterine life possible?
at late canalicular/early saccular stage
what happens in the embryonic stage of lung morphogenesis?
a single tube-the oesophagus branches off to form the trachea. Cells of the trachea are cuboidal and far from the blood vessels so gas exchange cannot take place
what happens in the pseudoglandular stage of lung morphogenesis?
lungs tissue resembles endocrine tissue, branching of bronchi and bronchioles takes place to form conductive airways. acinus formed
what is the canalicular stage of lung morphogenesis?
last generations of the lung periphery formed, epithelium differentiates into squamous epithelium and air-blood barrier is formed.
what is the saccular stage of lung development?
air spaces expand and surfactant is detectable in the amnionic fluid
what is the alveolar stage of lung morphogenesis?
secondary septation of alveoli which begins in utero but continues ater birth.
what is airway stenosis and in what stage of lung development is it likely to originate from?
narrowing of the airways, originates in the earlier stages of lung morphogenesis
what is airway malacia and in what stage of lung development is it likely to originate from?
trachea and bronchi are floppy, originates in earlier stages of lung morphogenesis
what is pulmonary agenesis/hypoplasia and in what stage of lung development is it likely to originate from?
incomplete development of the lungs, resulting in an abnormally low number or size of bronchopulmonary segments or alveoli, originates in earlier stages of lung morphogenesis
what is a tracheo-oesophageal fistula and in what stage of lung development is it likely to originate from?
abnormal connection between primitive gut and airway. originates in earlier stages of lung morphogenesis
what are bronchial cysts and in what stage of lung development is it likely to originate from?
congenital malformations of the bronchial tree, likely to occur in late stages of lung morphogenesis.
what is lobar emphysema and in what stage of lung development is it likely to originate from?
air can be drawn into the lungs but not expelled out. likely to occur in late stages of lung morphogenesis
what is cystadenomatoid malformation and in what stage of lung development is it likely to originate from?
varying number and sizes of cysts in one lobe of lung. occurs in later lung morphogenesis
what is sequestration and in what stage of lung development is it likely to originate from?
aberrant formation of segmental lung tissue that has no connection with the bronchial tree or pulmonary arteries occurs in later stages lung morphogenesis
when are there presenting features of developmental lung diseases?
- in fetal ultrasound
- in newborn
- in childhood or adulthood
what are the presenting features of developmental lung diseases in the newborn?
tchypnea respiratory distress (chest wall retraction)
what are the presenting features of developmental diseases in childhood and in adulthood?
stridor/wheeze
recurrent pneumonia
incidental finding
what are the symptoms of tracheo-bronchomalacia?
- barking/seal-like cough
- early onset/ recurrent croup
- breathlessness of exertion
- stridor/wheeze
what is the management of tracheo-bronchomalacia?
- airway clearance physiotherapy
- antibiotics
- NOT asthma treatment
what is a possible risk of Pulmonary adenomatoid malformation?
it may become malignant
how does the diaphragm develop?
membranes develop towards the centre of the embryo until the fuse in the centre
what may happen if the diaphragm doesn’t develop correctly?
diaphragmatic hernia
what cn a diaphragmatic hernia result in?
pulmonary hypertension and pulmonary hypoplasia
what is transient tachypnea of the newborn (wet lung)?
amnionic fluid remains in the lung after birth, resolves in 24-48hrs
what is a surfactant deficiency called?
hyaline membrane disease (respiratoty distress syndrome)
what causes hyaline membrane disease?
a build up of a membrane of dead cells and proteins in the alveoli caused by a deficiency of surfactant.
what is the treatment fro hyaline membrane disease?
- Antenatal glucocorticoids
- Surfactant replacement
- Supportive
until endogenous surfactant production by day 5
what are the antenatal causes of adult lung disease (COPD)?
- in utero nicotine exposure
- fetal infection
- maternal nutrition
- low birth weight/prematurity (antenatal steroids)
- maternal micronutrients/vitamins
what are the post-natal causes of adult lung disease?
- infection (Barker hypothesis)
- growth
- ETS (exposure to tobacco smoke) (+/- alpha 1 AT deficiency)
- environmental pollution
- micronutrients/vitamins
what is the chronic neonatal lung disease?
chronic inflammation in the lungs causes damage and scarring which reduces compliance.
what are some of the causes of chronic neonatal lung disease?
- antenatal infection
- barotrauma/ oxygen toxicity
- patent ductus arteriosus
- ventilation
- genetic
what does pre-natal nicotine exposure do to lungs?
-Lung hypoplasia
-Reduced alveolarisation
-Reduced lung function (small airways)
causing Increased incidence wheeze syndromes
-Increased susceptibility to infection
what does remodelling in asthma cause?
- Increased bronchial responsiveness
- Increase mucus secretion
- Airway oedema
- Airway narrowing
