Obstructive Airway Diseases

Question 1

What observations are seen in obstructive lung disease?

Answer 1

• There is AIRFLOW LIMITATION
• Peak Expiratory Flow Rate (PEFR) is reduced
• FEV1 is REDUCED
• FVC may be reduced
• FEV1 is less than 70% of FVC

Question 1

What is chronic bronchitis and emphysema better known as?

Answer 1

COPD

Question 2

Is bronchial asthma considered reversible or irreversible?

Answer 2

REVERSIBLE! Either spontaneously or as a result of medical intervention.
Bronchial smooth muscle contraction and inflammation can be modified by drugs

Question 3

What causes chronic bronchitis and emphysema?

Answer 3

• Smoking
• Atmospheric pollution
• Occupation
• Effect of age and susceptibility
• Prevalence
• Men > Women but…
• Increasing in developing countries

Question 4

What is an extremely rare case of emphysema?

Answer 4

ALPHA-1-ANTIPROTEASE (antitrypsin) deficiency

Question 5

How is chronic bronchitis defined clinically?

Answer 5

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

(excludes TB, bronchiectasis etc)

Clinically may be confused with Chronic bronchial asthma

Question 6

Morphological changes in chronic bronchitis

Answer 6

LARGE AIRWAYS
- Mucous gland hyperplasia
- Goblet cell hyperplasia
- Inflammation and fibrosis is a minor component
SMALL AIRWAYS
- Goblet cells appear
- Inflammation and fibrosis in long standing disease

Question 7

Pathogenesis of emphysema

Answer 7

• SMOKING
• Protease - antiprotease imbalance
• Ageing
• Alpha-1-antitrypsin deficiency

Question 8

COPD: why hypoxemia?

Answer 8

• Ventilation / Perfusion abnormality (mismatch)
  ~ Airway Obstruction
• Alveolar Hypoventilation
  ~ Reduced Respiratory Drive
• Diffusion Impairment
  ~ Loss of Alveolar Surface Area
• Shunt
  ~ Shunt - Only during severe acute infective exacerbation

Question 9

What is physiological pulmonary arteriolar vasoconstriction?

Answer 9

• When alveolar oxygen tension falls
• Can be localised effect
• All vessels constrict if there is hypoxaemia

Question 10

What leads to pulmonary hypertension?

Answer 10

Global pulmonary arteriolar narrowing

Question 11

WHERE MUST BLOOD NOT BE SENT WHEN PROTECTIVE MECHANISM HAS KICKED IN?

Answer 11

alveoli which are short of oxygen

Question 12

Define FEV1

Answer 12

Forced Expiratory Volume of air exiting the lung in the first second of this exercise
(Normal FEV1 is about 3.5 – 4 litres)

Question 13

Define FVC

Answer 13

Final Total amount or air expired
(Normal FVC is about 5 litres)

Question 14

What are the forms of emphysema?

Answer 14

• Centriacinar - holes in the top part of the lung (cig smokers)
• Panacinar - holes in the bottom part of the lung (cig smokers)
• Periacinar
• Scar