Lecture 54 -- Pulmonary Pathology and Lung Injury

Question 1

what are the three causes of pulmonary edema ?

Answer 1

§ 1) Hemodynamic (hydrostatic): No Pneumocyte/Alveolar Damage

		§ 2) Non Hemodynamic: ALVEOLAR INJURY 

		§ 3) Idiopathic causes

Question 2

describe the histology of Hemodynamic pulmonary edema

Answer 2

□ 2 Early Abnormalities:
◊ Alveoli Filled with Light pink fluid (transudate)
◊ Septa are congested with RBCs but otherwise OK (think traffic jam)

□ Later Abnormality: Hemosiderin
◊ Red Cells escape into the alveolar spaces
◊ Hemosiderin Laden Macrophages (brown granular material

Question 3

What are the three phases of alveolar injury

• what is DAD ?

Answer 3

Acute Lung Injury – Diffuse alveolar Damage (DAD)

Sub-acute — Organizing DAD

Chronic – dense fibrosis

Question 4

Acute Lung Injury – what are the 2 clinical settings

Answer 4

• Acute Respiratory Distress Syndrome (ARDS)

Idiopathic (Acute interstitial Pneumonia )

Question 5

What causes ARSD –

Answer 5

§ Infectious
§ Noninfectious – trauma; embolisms (air, fat, amniotic fluid), radiation, drug overdose, gastric aspiration
§ Other – Pancreatitis, Immune, DIC,

Question 6

Describe the pathogenesis of acute DAD ?

Answer 6

toxin in the blood that has a propensity to injury the capillaries of the alveoli

§ Injury to alveolar wall –> cytokines –> neutrophil accumulation –> cytokines –> Macrophages

§ Chemo attractant Cytokines, activated endothelial cells, macrophages activated

§ Results in pneumocyte death/inflammation

Question 7

Histology of acute DAD

Answer 7

◊ Edema – faint pink within the alveolar spaces

◊ Hyaline -- Dark pink Circles; lining the alveolar sacs (acting as next best thing from leaking blood into alveolar spaces)

Question 8

what comes after acute lung injury?
what are some defining characteristics on histo?
whats the difference between Diffuse Organizining DAD and Localized Organized PNA ?

Answer 8

Organizing alveolar lung injury

Characteristics: fibroblats/loose fibrosis; regenerative pneumocytes

diffuse vs localized — self explanatory

Question 9

type 1 vs type 2 pneumocytes –
differences in shape
which can regnerate

Answer 9

type 1 – flat; thin; covers large surface area; cannot regenerate

type 2 – budding; can regenreate to form type 1 pneumocytes