Atelectasis and ARDS - Rao Flashcards
What is atelectasis?
When part or all of the lung is collapsed
What are the four types of atelectasis?
Resorption
Compression
Neonatal (loss of surfactant)
Contraction
What causes resorption atelectasis (general)?
A bronchial becomes obstructed, so air can not flow into the space; lung tissue collapses.
What does a resorption atelectasis look like clinically?
fever
ipsilateral tracheal deviation
ipsilateral diaphragm elevation
absent tactile fremitus
What causes compression atelectasis?
air or fluid accumulation in the plural cavity which collapses the lung
What does compression atelectasis look like clinically?
contralateral traheal deviation
increased tactile fremitus
What causes neonatal atelectasis?
loss of surfactant
What synthesizes surfactant and what proteins are present?
synthesized by type 2 pneumocytes
contains phosphatidylcholine, phosphatidylglycerol, and surfactant proteins
What are the surfactant proteins responsible for?
Surfactant proteins A and D contribute to innate immunity
Surfactant proteins B and C contribute to surface tension reduction
What hormones control synthesis of surfactant?
cortisol and thyroxine (increase production)
insulin (decrease production)
What three things might cause neonatal atelecatasis?
premature birth
maternal diabetes
cesarean section
How does neonatal atelectasis differ from compression or resorption atelectasis on histology?
collapsed neonatal alveoli are lined by hyaline membranes
What appears on x-ray in neonatal atelectasis?
“ground glass”
no tracheal deviation
What causes contraction atelectasis?
global fibrosis of the lungs which prevent full expansion
What is acute lung injury?
Any trauma to the epithelial or endothelial lung tissue
this is a VERY GENERAL term and is used more as a pathology for a diagnosis rather than a diagnosis itself
