Acute Lung Injury

Question 1

What is the source of most pulmonary emboli?

Answer 1

deep veins of the leg and usually a complication of an underlying disorder such as immobilization or genetic hypercoaguability

Question 2

The consequence of emboli depends on what?

Answer 2

the size of the embolus and the status of circulation- large size or inadequate circulation can result in infarction rarely

Question 3

Emboli cause what kind of necrosis?

Answer 3

coagulative

Question 4

What happens to infarcted lung over time?

Answer 4

the tissue will start to organize and become paler due to conversion of hemorrhage to hemosiderin by macrophages and will eventually become a contracted star

Question 5

Amniotic fluid emboli are characterized by what?

Answer 5

wavy purple keratin debris on microscopic appearance

Question 6

What are some common causes of edema?

Answer 6

• CHF
• liver disease (decreased oncotic pressure)
• infections, inhaled gases, shock

Question 7

What happens in CHF?

Answer 7

The pulmonary vessels are engorged, the lungs are heavy and blood can be expressed from the cut surface and a foamy exudate can be seen.

Question 8

What causes the pink substance in the alveoli in edema microscopically?

Answer 8

proteins in the exudate that have stained

Question 9

What is the difference between passive and active congestion of the lungs?

Answer 9

active- inflammatory

passive-increased hydrostatic pressure

Question 10

What is a hallmark of passive congestion of the lung?

Answer 10

hemosiderin-laden macrophages (brown) due to alveolar micro hemorrhages from the increase in pressure

Question 11

What are some causes of ARDS?

Answer 11

• infection
• trauma/near-drowning
• pancreatitis
• uremia
• transfusions

Question 12

How does ARDS present?

Answer 12

diffuse alveolar capillary damage with rapid, severe onset resulting in hypoxia and decreased ATP formation and associated with high death rate

Question 13

What are the stages of ARDS?

Answer 13

• acute (exudative)

- organizing (proliferative)

Question 14

What happens in the acute phase of ARDS?

Answer 14

endothelial injury leads to vascular leakage resulting in edema, then eosinophilic hyaline membrane formation, and even atelectasis

Question 15

What happens in the organizing phase of ARDS?

Answer 15

type II pneumocyte proliferation and interstitial inflammation leads to organization and either recovery, interstitial fibrosis, or death

Question 16

Are hyaline membranes common in the organizing stage of ARDS?

Answer 16

not so much anymore

Question 17

Note about organizing phase

Answer 17

Hyaline membranes have been resorbed and replaced with plugs of idntraalveolar organizing fibroconnective tissue, which stain blue-green with a trichrome stain

Question 18

What does the microscopic appearance of the acute phase of ARDS resemble?

Answer 18

Neonatal Pulmonary Disease (hyaline membrane appearance)

Question 19

Deficiencies in both pulmonary surfactant and the fibrinolysis system are believed to be involved in what?

Answer 19

hyaline membrane disease

Question 20

An autopsy of an elderly patient who expired in CHF shows a hemorrhagic pleural effusion and a peripheral wedge-shaped lesion in the right lower lobe. What is the most likely cause?

Answer 20

Pulmonary infarct