Developmental Aspects of Lung Disease Flashcards
Lung morphogenesis
Embryonic Pseudo-glandular Canalicular Saccular Alveolar
Embryonic
Evolves from primitive gut
Pseudo-glandular
Looks like adult endocrine tissue
Primitive lungs/trachea
Start to develop lobes
Begin to develop gas exchange mechanism
Canalicular
Extra-uterine life becomes possible
Squamous epithelium develops
Gas exchange possible
Post-natal lung growth
Alveolar septation continues
Presenting features
Fetal ultrasound
Newborn - tachypnoea, respiratory distress (chest wall retraction)
Childhood - stridor/wheeze, recurrent pneumonia, incidental finding
“Common” congenital lung disease
Tracheo-bronchomalacia -
Barking cough
Early onset/recurrent croup (viral infection - inflammation of voice box)
Breathless on exertion
Stridor/wheeze
Management - Airway clearance physio, antibiotics (avoid asthma treatment), naturally resolves over time
Bronchodilators
Muscle relaxant
In common congenital lung disease - closes airways as not enough cartilage to keep them open
Functional changes in lungs at birth
From fluid secretion to fluid absorption
Wet lung if transition from breathing fluid to air does not happen fast enough
Neonatal lung disease
Surfactant deficiency
Treatment - antenatal glucocorticoids (given to mother to stimulate surfactant production - surfactant system sensitive to steroids)
Chronic neonatal lung disease
As a result of antenatal infection, barotrauma, PDA, genetic
Increased childhood respiratory morbidity
Fetal/paediatric origins of adult lung disease
Antenatal - in utero nicotine exposure, fetal infection, maternal nutrition, low birth weight/prematurity
Post-natal - infection, growth, environmental pollution, micronutrients/vitamins
Remodelling
Alteration of structure following an external influence
Pre-natal nicotine exposure - lung hypoplasia, reduced alveolarisation, reduced lung function (small airways), increased susceptibility to infection
Interference of intercellular signalling
Asmthma remodelling
Chronic inflammation Increased bronchial responsiveness increased mucus secretion Airway oedema Airway narrowing
