Lecture 11: COPD

Question 1

COPD definition

Answer 1

Collection of conditions characterized by persistent expiratory airflow limitation that is not fully reversible associated w/ enhanced inflammatory response and exacerbations

Question 2

Big FEV1 / FVC difference between COPD and asthma

Answer 2

Ratio cannot NORMALIZE even after administration of bronchodilator

Question 3

Chronic bronchitis definition

Answer 3

Chronic, productive cough on most days for at least 3 months a year

Question 4

Chronic bronchitis pathology

Answer 4

Hypertrophy/hyperplasia of mucus glands, bronchial wall inflammation/fibrosis –> bronchial wall thickening (edema, BM thickening, increased SM) with decreased luminal size

Question 5

Chronic bronchitis is a _________ dx; emphysema is a _________ dx

Answer 5

Clinical; pathological

Question 6

Describe emphysema

Answer 6

Destruction of lung parenchyma and enlargement of air spaces distal to terminal bronchiole

Question 7

Types of emphysema and description

Answer 7

Centrilobular (proximal acinar): predominantly involves respiraotry bronchiole and upper lungs, smokers; Panlobular (panacinar), lower lungs, see in alpha1-antitrypsin deficiency

Question 8

What does alpha-1 antitrypsin do?

Answer 8

Inhibitor of neutrophil elastase, which is a proteolytic enzyme that degrades elastin

Question 9

How does smoking involve the protease-antiprotease theory?

Answer 9

Inactivates alpha-1 antitrypsin and recruits neutrophils

Question 10

Variants in alpha-1 antitrypsin disease and which is more dangerous and which is more common

Answer 10

Z-variant (more dangerous) and S-variant (more common)

Question 11

Z-variant

Answer 11

Failure to form alpha-1 antitrypsin salt bridge leading to slowly folding protein that form globules that are never secreted and accumulate hepatocytes (cirrhosis)

Question 12

S-variant

Answer 12

Renders alpha-1 antitrypsin more susceptible to proteolysis; not associated with intracellular accumulation

Question 13

Emphysema: lung compliance increased or decreased

Answer 13

Increased!

Question 14

What is the equal pressure point?

Answer 14

Point at which the pressure within the bronchus and within the chest cavity are equal

Question 15

Why is there decreased trans pulmonary pressure in emphysema?

Answer 15

Because the lungs are more compliant (less stiff), they cannot withstand a strong pressure differential

Question 16

Why does a decreased trans pulmonary pressure impact emphysema?

Answer 16

You reach the EPP earlier, meaning that on expiration, there is obstruction

Question 17

What does decreased airway tethering mean?

Answer 17

Fewer “tethers” of the airways mean they cannot be open fully (decreased diameter)

Question 18

FRC and TLC in ephysema. What about VC?

Answer 18

FRC is larger because of increased compliance, TLC is increased (hyperinflation); VC is reduced

Question 19

Mechanical disadvantage in ephysema

Answer 19

Enlarged lungs –> flattened diaphragm –> less strength of diaphragm (dyspnea)

Question 20

Describe dynamic hyperinflation in a patient with COPD during exercise

Answer 20

They struggle with breathing out, meaning less time to breath out, so their end expiratory lung volume INCREASES as minute vent increases

Question 21

V/Q in chronic bronchitis

Answer 21

Problem with airway leads to V/Q mismatch

Question 22

V/Q in emphysema

Answer 22

Destroyed whole unit (alveolus and capillary), so may not get hypoxemia

Question 23

Alveolar hypoventilation in emphysema

Answer 23

Increased work of breathing –> decreased central ventilatory drive AND increased dead space due to tissue destruction (this area is ventilated but not perfused = V/Q mismatch)

Question 24

Symptoms of COPD

Answer 24

Dyspnea, cough (w/ sputum), exacerbations

Question 25

What precipitates an exacerbation?

Answer 25

Viral infections, pollution, bronchospasm

Question 26

Exam findings with emphysema

Answer 26

Prolonged expiratory phase, decreased breath sounds, wheezing (expiratory), ronchi

Question 27

Exam findings with severe emphysema/COPD

Answer 27

Barrel-shaped chest, purse-lipped breathing (increases pressure in airways to stent open airways), emaciation

Question 28

How can you see emphysema on X-ray/CT?

Answer 28

Hyperinflation by counting ribs and “moth eaten” appearance on CT

Question 29

Causes of pulmonary HT in COPD

Answer 29

Hypoxia and other vessel changes, thromboembolism, parenchymal destruction (decreased vessels), LV dysfunction, hyperinflation

Question 30

Chronic bronchitis and smoking (3 histological changes)

Answer 30

Mucus hypertrophy and hyperplasia, broncial wall inflammation, impaired mucociliary clearance

Question 31

Chronic emphysema and smoking (2 histological changes)

Answer 31

Increased number of neutrophils –> increased elastase, oxidation of alpha-1 antitrypsin –> decreased function

Question 32

What are other risk factors for emphysema?

Answer 32

Occupational exposures and indoor air pollution (cooking with biomass fuels)

Question 33

Blue bloater

Answer 33

Chronic bronchitis: overweight, cyanotic, elevated Hb, peripheral edema, ronchi and wheezing

Question 34

Pink puffer

Answer 34

Emphysema: older and thin, severe dyspnea, quiet chest, xray: hyperinflation with flattened diaphragm

Question 35

What is the diagnostic requirement for COPD?

Answer 35

Airflow obstruction: you can have ephysema and chronic bronchitis without COPD

Question 36

How is COPD a systemic disease?

Answer 36

SYSTEMIC inflammation related to ischemic HD, osteoporosis, metabolic syndrome, depression via systemic inflammation

Question 37

Emphysema tx

Answer 37

Proven survival benefit: smoking cessation and supplemental O2 for hypoxemic pts

Question 38

Emphysema sx management

Answer 38

Inhaled bronchodilators and corticosteroids

Question 39

Describe lung volume reduction surgery

Answer 39

Reduces lung volume to reduce physiologic dead-space, increases elastic recoil, improve mechanic functioning of diaphragm