pathology of obstructive airway diseases

Question 1

which three conditions are obstructive airway diseases?

Answer 1

emphysema
chronic bronchitis
asthma

Question 2

which two conditions together are called COPD?

Answer 2

emphysema and chronic bronchitis

Question 3

what is predicted FVC based on?

Answer 3

age, sex and height

Question 4

what is a marked fall in PEFR?

Answer 4

<50% of best

Question 5

what is a moderate fall in PEFR?

Answer 5

50-80% of best

Question 6

in obstructive lung disease what happens to PEFR, FEV1 and FVC?

Answer 6

reduced (FVC may be reduced)

Question 7

what is FEVcompared to FVC in obstructive lung disease?

Answer 7

<70%

Question 8

what causes airway narrowing in bronchial asthma?

Answer 8

1. inflammation and oedema

2. twitching/contraction of smooth muscle

Question 9

when can bronchial asthma become irreversible?

Answer 9

when it becomes chronic

Question 10

what is the aetiology of COPD?

Answer 10

• smoking
• atmospheric pollution
• occupation: dust

Question 11

what is your susceptibility to COPD?

Answer 11

how your metabolism handles the chemicals in cigarettes or pollution.

Question 12

does congenital alpha 1 antitrypsin deficiency cause chronic bronchitis?

Answer 12

no, only emphysema

Question 13

what is the clinical definition of COPD?

Answer 13

• Cough productive of sputum most days
• in at least 3 consecutive months
• for 2 or more consecutive years

Question 14

what are the morphological changes in chronic bronchitis in the large airways?

Answer 14

• mucous gland hyperplasia
• goblet cell hyperplasia
• inflammation and fibrosis is a minor component

Question 15

what are the morphological changes in chronic bronchitis in the small airways?

Answer 15

• goblet cells appear

- Inflammation and fibrosis in long standing disease

Question 16

what is the pathological definition of emphysema?

Answer 16

Increase beyond the normal in the size of airspaces distal to the terminal bronchiole arising either from dilatation or from destruction of their walls and without obvious fibrosis.

Question 17

what is centri-acinar emphysema?

Answer 17

loss of alveolar tissue around the middle of the acinus (around the bronchioles)

Question 18

what type of emphysema is associated with smoking?

Answer 18

centri-acinar

Question 19

where does centri-acinar emphyema normally occur?

Answer 19

in the apex of the lung

Question 20

whar is pan-acinar emphysema?

Answer 20

emphysema that causes a “total wipeout” of aleolar tissue, alveolar tissue is lost everywhere

Question 21

what type of emphysema occurs in congenital alpha 1 antitrypsin deficiency?

Answer 21

pan-acinar

Question 22

what is peri-acinar emphysema?

Answer 22

loss of aveolar tissue at the distal end of acinar

Question 23

how can peri-acinar emphysema cause a pneumothorax ?

Answer 23

Bullae (large air spaces) rupture and air enters the pleural space form the lung

Question 24

what does smoking do to cause emphysema?

Answer 24

it induces the production of neutrophils and macrophages. These produce proteases such as elastase. These damage lung tissue. Normally the body has ways to prevent damage from these enzymes. However, smoking inhibits these processes: it inhibits anti-elastase and other anti-proteases such as alpha 1 antitrypsin, it also inhibits the repair mechanisms of the lung and elastin synthesis.

Question 25

what are the reversible components of COPD (with pharmacological intervention)

Answer 25

• smooth muscle contraction

- inflammation

Question 26

what are alveolar attachments?

Answer 26

where alveolar tissue attaches to the bronchioles.

Question 27

what causes the collapse of bronchioles on expiration in emphysema?

Answer 27

the loss of alveolar attachments so they are no longer able to hold open the bronchioles druing the pressure exerted on them on expiration.

Question 28

what are the 4 abnormal states associated with hypoxaemia ?

Answer 28

• Ventilation / Perfusion imbalance (V/Q)
• Diffusion impairment
• Alveolar Hypoventilation
• Shunt

Question 29

why does airway obstruction cause hypoxaemia?

Answer 29

oxygen can’t get to alveoli to diffuse into the blood.

Question 30

why does reduced respiratory drive cause hypoxaemia?

Answer 30

the central chemoreceptors in people with copd will become sensitised to carbon dioxide as it will be constantly high. So the drive to breath comes from PO2

Question 31

why does loss of alveolar surface area cause hypoxaemia?

Answer 31

less surface area for gas exchange so O2 levels drop

Question 32

why does hypoxaemia occur during acute infective exaceration?

Answer 32

pus in the alveoli prevents gas exchange

Question 33

what is a ventilation/perfusion mismatch?

Answer 33

some ventilation of abnormal alveoli, just not enough

Question 34

what is shunt?

Answer 34

no ventilation to abnormal alveoli. So blood is unoxygenated when it passes through the lung and enters the left side of the heart

Question 35

which conditions cause ventilation/ perfusion mismatch?

Answer 35

bronchitis

bronchopneumonia

Question 36

which conditions cause shunt?

Answer 36

severe bronchopneumonia

Question 37

what is FIO2?

Answer 37

the fraction of inspired air which is oxygen

Question 38

does shunt respond to increase in FIO2 treatment?

Answer 38

no

Question 39

how can hypoventilation be treated?

Answer 39

raising PIO2

Question 40

what is chronic (hypoxic) cor pulmonale?

Answer 40

hypertrophy of the right ventricle resulting from disease affecting the function and or structure of the lung. Vasoconstriction of arterioles in the lung, loss of capillary beds and secondery polycythaemia increases pulmonary arterial pressure so right side of the heart has to work harder.

Question 41

which abnormal states cause type I respiratory failure?

Answer 41

shunt and V/Q mismatch

Question 42

which abnormal states cause type II respiratory failure?

Answer 42

alveolar hypoventilation