Flashcards in Atelectasis and ARDS - Rao Deck (21)
What is atelectasis?
When part or all of the lung is collapsed
What are the four types of atelectasis?
Neonatal (loss of surfactant)
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?
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?
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?
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
What problems result from acute lung injury?
Diffuse Alveolar Damage (ARDS)
What are the biggest causes of ARDS?
Diffuse Lung Infections
What can be seen clinically in ARDS?
Hypoxemia that DOESN'T respond to O2 therapy
What happens to the lung during ARDS?
-macrophages release cytokines
-neutrophils migrate to the lung
- fibrin forms hyaline membranes
-pneumocytes are damaged
-surfactant deficiency leads to atelectasis
What is seen histologically in ARDS?
hyperplastic type 2 pneumocytes