W4 - Obstructive Lung Diseases

Question 1

Name 4 obstructive airway diseases

Answer 1

Chronic bronchitis
Emphysema
COPD (Chronic bronchitis + emphysema)
Asthma

Question 2

Define FEV1 and FVC

Answer 2

FEV1 is Forced Expiratory Volume - air exiting lung in first second

FVC - Final total of air expired

Question 3

What is the typical value of FEV1 and FVC in litres and as a ratio? How does obstructive disease change these values?

Answer 3

FEV1:FVC ratio: 70-80% (or 0.7-0.8)
FEV is 3.5 - 4 litres
FVC is 5 litres

In obstructive disease:
FEV1 is reduced
FVC may be reduced
Ratio is less than 70%

Question 4

How are spirometry valuees predicted?

Answer 4

Predicted FVC is based on age, sex and height

Question 5

What is normal PEFR value?

Answer 5

400 - 600 litres/min

Question 6

Which obstructive disease is a Type I Hypersensitivity Response? Mast cell degranulation leads to what two things?

Answer 6

Bronchial asthma

Mast cell degranulation leads to factors attracting inflammatory cells and factors causing smooth muscle contraction

Question 7

The airway of chronic asthma exhibits what 5 features?

Answer 7

Inflammation
Oedema
Mucus
Plasma exudation
Epithelial shedding/damage

Question 8

Name 7 COPD aetiologies

Answer 8

Smoking
Air pollution
Jobs
Alpha-1 Antitrypsin deficiency
Age and susceptibility
Men more than women
Developing countries increasing

Question 9

Provide the clinical definition of chronic bronchitis

Answer 9

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

Question 10

When does chronic bronchitis become complicated chronic bronchitis? (2 ways)

Answer 10

When sputum turns mucopurulent
or FEV1 falls

Question 11

What morphological changes does chronic bronchitis lead to in large airways? (3 ways)

Answer 11

Mucous gland hyperplasia

Goblet cell hyperplasia

Inflammation and fibrosis is a minor component

Question 12

What morphological changes does chronic bronchitis lead to in small airways? (2 ways)

Answer 12

Goblet cells appear

Inflammation and fibrosis in long standing disease

Question 13

Provide the pathological definition of emphysema

Answer 13

Increase beyond normal size of airspaces distal to terminal bronchiole arising from dilation or destruction of their walls, without obvious fibrosis

Question 14

Name 4 forms of emphysema

Answer 14

Centriacinar
Panacinar
Periacinar
Scar “irregular” / bullous emphysema

Question 15

What is the most common form of emphysema? What is it characterised by? Where does it occur in the lung? What is it most associated with?

Answer 15

Centriacinar Emphysema

Where tissue around acini are damaged, making holes in the middle of them

Occurs in upper lobes

Associated with smoking

Question 16

What is panacinar emphysema characterised by? What causes it? Where does it happen in lungs?

Answer 16

Rare emphsema where whole acini is destroyed

Caused by Alpha-1 Trypsin Deficiency

Tends to be base of lungs

Question 17

What is periacinar emphysema? What complication can it lead to?

Answer 17

Damage on edge of acini, with space under pleura. Spontaneous busting can cause pneumothorax

Question 18

What is a bulla and bleb?

Answer 18

Bulla - an emphysematous space of 1cm+

Bleb - describes the space just under pleura

Question 19

What 3 things cause emphysema?

Answer 19

Smoking
Ageing
Alpha-1 Antitrypsin Deficiency

Question 20

While COPD is irreversible, which 2 mechanisms of the disease respond to pharmacological intervention?

Answer 20

Smooth muscle tone

Inflammation

Question 21

What 4 things cause hypoxaemia in COPD?

Answer 21

Airway obstruction
Reduced respiratory drive
Loss of alveolar surface area
Shunt (during severe acute infective exacerbation)

Question 22

Explain the steps leading to cor pulmonale in COPD

Answer 22

1. Alveoli short of oxygen
   
   2. Pulmonary arteriolar vasoconstriction to avoid sending blood to oxygen-poor alveoli.
   3. Pulmonary hypertension
   4. Muscle hypertrophy in pulmonary arterioles and intimal fibrosis
   5. Loss of capillary bed
   6. Secondary polycythaemia
   7. Bronchopulmonary arterial anastamoses
      Hypertrophy of right ventricle, affecting function and/or structure of lung