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90 Cards in this Set
- Front
- Back
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How many lobes are in the right lung?
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3
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How many lobes are in the left lung?
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2
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What is the right bronchus like compared to the left?
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Wider, shorter, and steeper.
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What is the implication of the right lung being wider shorter and steeper?
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If a kid aspirates a foreign object it will more likely go down into the right lung than left.
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What structures are found at the hilus of the lung?
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The bronchial bundle:
-Bronchus -Artery -Lung |
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What is the normal feeling that you'll get if you press on a lung during autopsy?
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Crepitus - due to the air filled alveolar sacs.
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What is a lack of crepitus?
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Pathologic
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What is the histology of the epithelial lining of the upper respiratory airways?
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Pseudostratified ciliated columnar
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What is the last level of pseudostratified ciliated columnar epithelium?
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The terminal bronchioles
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Where does gas exchange begin in the airway?
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At the respiratory bronchioles.
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Where does a respiratory acinus begin?
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Just distal to a terminal bronchiole.
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What is an alveolar wall made up of?
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-Endothelial cells of capillaries
-Pneumocytes (Type I and II) |
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Where are type I pneumocytes?
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Covering the endothelial cells
-95% of all pneumocytes |
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Where are type II pneumocytes?
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Seen sticking out of the alveolar walls
-5% of all pneumocytes |
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What is the function of the type I pneumocytes?
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To be a protective covering of the alveolar wall/capillary
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What are the 2 functions of type II pneumocytes?
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-Produce surfactant
-Repair the alveolar epithelium |
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Define Atelectasis:
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A state in which the lung is collapsed - without air.
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Does atelectasis mean the WHOLE lung is collapsed?
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No; it may be all or part.
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What type of atelectasis do we see in premature neonates?
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Incomplete expansion
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What type of atelectasis is more common, and what we see in adults?
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Collapse of previously inflated lung
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List the 3 main mechanisms of collapse atelectasis:
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1. Resorption (obstruction)
2. Compression 3. Contraction |
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What causes resorption atelectasis?
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Complete obstruction of the airway.
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Why is it called resorption atelectasis?
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Because when the airway is obstructed the blood continues to flow and eats up the air that was in the alveoli.
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What direction does the mediastinum shift in Resorption Atelectasis?
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To the pathologic side
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What are the 4 causes of Resorption atelectasis?
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1. Bronchial asthma
2. Chronic bronchitis 3. Bronchiectasis 4. Aspiration of foreign bodies |
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Do bronchial neoplasms commonly cause resorption atelectasis? Why?
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No - because they don't usually totally occlude the airway; neoplasms more often make the alveoli expand and cause emphesyma.
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What is bronchiectasis? Why/how does it cause obstructive atelectasis?
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Irreversible dilation of the airways resulting in inability to clear mucus; results in airway obstruction
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What is the main thing that causes compression atelectasis?
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Something abnormal in the pleural space
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What are 3 things that can be found in the pleural cavity?
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1. Exudate
2. Blood (hemothorax) 3. Air (pneumothorax) |
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In what patients are compression atelectasis more commonly seen?
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1. CHF
2. Cancer patients with neoplastic effusions |
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What is the main difference between Resorption and Compression atelectasis?
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Resorption: mediastinum shifts TOWARD the pathologic lung
Compression: mediastinum shifts AWAY |
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What is Contraction Atelectasis?
What is the cause of it? |
Airflow obstruction because the lungs are unable to expand;
Cause: fibrosis in the lungs or pleura |
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Which type of atelectasis is irreversible?
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Contraction atelectasis
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What are the 2 main consequences of atelectasis?
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-Reduced oxygenation
-Infection |
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What is the "INJURY" in acute lung injury?
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Injury to the epithelium or endothelium of the lung alveolar walls.
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What is the more common injury in ALI?
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Endothelial
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What causes Acute lung injury?
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A number of things
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Is acute lung injury inherited?
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No
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What inheritable factors do affect ALI? How?
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Factors that determine the response to injury and survival
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What mediators are important in acute lung injury?
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TNF
IL-1, 6, 10 TGF-beta |
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What are the 3 main chronological manifestations of ALI?
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1. Pulmonary edema
2. DAD 3. Organizing pneumonia |
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What is the major problem in acute lung injury?
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Pulmonary edema
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What are 3 possible underlying mechanisms to the development of pulmonary edema in ALI?
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1. Hemodynamic disturbances
2. Microvascular injury 3. Undetermined (idiopathic) |
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Why is it important to determine the underlying mechanism of pulmonary edema?
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Because it determines how you treat the ALI and what its outcome will be.
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What type of hemodynamic disturbance causes pulmonary edema leading to ALI?
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Cardiogenic
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What is cardiogenic pulmonary edema? How does it manifest?
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Blockage of pulmonary fluid resorption due to volume/pressure overload in the left heart.
Manifestation: HEAVY WET LUNGS |
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Where does the pulmonary edema begin when it is cardiogenic?
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In the basal regions of the lower lobes.
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What is the HALLMARK of cardiogenic pulmonary edema?
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Heart failure cells
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What are heart failure cells?
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Macrophages that have eaten RBCs that were put into the lung edema via hemorrhage.
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What color do you see in the lungs when heart failure cells accumulate? What is this called?
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Brown - Hemosiderin
"Brown Induration" |
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What type of pulmonary edema that causes ALI is more intrinsic to the lungs?
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Microvascular injury
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What is most often the cause of microvascular injury?
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Damage to the CAPILLARIES (endothelial cells)
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What is less commonly the cause of microvascular injury?
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Damage to the epithelial cells (pneumocytes)
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How does microvascular injury cause edema?
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It allows for leakage of fluid and proteins into the interstitial space and alveoli
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What are 2 types of microvascular injury that can be seen? Which is worse?
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-Localized - predisposes to infection so not as bad
-Diffuse leads to DAD - WORSE |
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What is DAD?
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Diffuse alveolar damage
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What are 2 synonyms for DAD?
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Shock lung
Acute alveolar injury |
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What is the clinical syndrome produced by DAD called?
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ARDS
-acute resp distress syndrome |
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so Acute Respiratory Distress Syndrome (ARDS) refers to:
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Diffuse Alveolar damage caused by microalveolar damage - mainly dmg to endothelial cells.
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What are 3 main chronological clinical manifestations of ARD syndrome?
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1. Respiratory insufficiency and cyanosis
2. Arterial hypoxemia 3. Possibility for progression to multi-organ system failure |
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Why is the respiratory insufficiency so bad?
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Because it is severe and life-threatening.
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How is the respiratory insufficiency manifested?
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By blue cyanosis
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Why is the arterial hypoxemia so bad?
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Because it is refractory to oxygen therapy - the lungs are filled with fluid and oxygen can't get in.
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Why is giving oxygen to a person with ARDS due to microvascular injury silly?
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Because it's like flogging a dead horse.
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How is ARDS diagnosed?
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By seeing bilateral diffuse alveolar infiltration of edema on CXR
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Is there just one cause of ARDS?
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No, there are a variety of conditions associated with it.
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What are 4 specific conditions associated with the development of ARDS?
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1. Sepsis
2. Diffuse lung infections 3. Gastric aspiration (pneumo) 4. Mechanical (head trauma) |
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What is an inhaled irritant that can cause ARDS?
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Oxygen!
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What is Step #1 in developing ARDS?
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Damage to epithelial or endothelial walls of alveoli
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What is step #2 in ARDS? (four components)
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-Increased vascular permeability
-Alveolar flooding w/ edema -Loss of gas diffusion capacity -Damage to type II pneumocytes |
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What is the result of loss of type II pneumocytes?
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Surfactant abnormalities
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Why does RDS develop in infants/newborns?
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Because their type II pneumocytes have deficiency of surfactant secretion.
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What is the tissue manifestation of increased vascular permeability that causes step #3 of ARDS?
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Exudation and formation of a hyaline membrane
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What results from exudation and hyaline membrane formation?
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Tissue destruction within the alveoli
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What is the end stage of ARDS that happens in the long term?
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Organization and scarring
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Why is end stage lung bad?
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Because it is fibrotic, scarred, and nonfunctional.
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Why does a hyaline membrane form in DAD?
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The increased vascular permeability allows chemotaxis of WBCs into the alveolus
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What do PMNs do once inside the alveolus?
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Secrete inflammatory molecules that cause damage to the alveolar structures.
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What happens as a result of alveolar tissue damage?
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Edema fluid infiltrates into the alveolus, mixes with cell debris, and forms a hyaline membrane.
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What does ARDS look like on microscopic exam?
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Pink membranes around the alveolar sacs - shouldn't normally be there.
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What develops later on microscopic exam of ARDS lung biopsy?
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Hyperplasia of the pneumocytes
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So the 2 main process that occur in the first week of ARDS are:
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1. Edema (day 1, maybe 2)
2. Hyaline membrane formation (days 3-6) |
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What 2 processes occur from day 7 and beyond in ARDS?
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-Inflammation
-Interstitial fibrosis |
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What portion of patients with ARDS survive the interstitial inflammatory stage?
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~50%
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What happens to the other 50%?
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They die as a result of interstitial fibrosis immediately
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If patients do survive the organization stage, what do they have the potential for?
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Death due to end stage lung and severe fibrosis.
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What are the steps in the typical clinical course of ARDS? (5)
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1. Hospitalization for triggering condition
2. Tachypnea/dyspnea 3. Cyanosis/hypoxemia 4. Respiratory acidosis 5. Respiratory failure |
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What is the overall mortality rate of ARDS?
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~60%
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What is Acute interstitial pneumonia?
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Acute lung injury with a rapidly progressive course similar to ARDS
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What is the cause of Acute interstitial pneumonia?
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Unknown
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