Airflow Obstruction

Question 1

How is airflow obstruction diagnosed?

Answer 1

Spirometry showing reduced FEV1 and reduced FEV1/FVC ratio.

Question 2

What spirometry pattern indicates obstruction?

Answer 2

Low FEV1 with low FEV1/FVC ratio.

Question 3

Why is spirometry essential?

Answer 3

Symptoms alone cannot distinguish asthma, COPD, or bronchiectasis.

Question 4

What happens to airway cross-sectional area peripherally?

Answer 4

It increases markedly.

Question 5

Why does narrowing of a large airway cause early symptoms?

Answer 5

Large airways contribute significantly to resistance.

Question 6

Why can small airway disease be asymptomatic initially?

Answer 6

Large total cross-sectional area masks early obstruction.

Question 7

Relationship between resistance and airway radius?

Answer 7

Resistance is inversely proportional to radius (Poiseuille’s law).

Question 8

Three common obstructive airway diseases?

Answer 8

Asthma, COPD, bronchiectasis.

Question 9

Definition of asthma?

Answer 9

A heterogeneous disease with chronic airway inflammation and variable expiratory airflow limitation.

Question 10

Key symptom pattern in asthma?

Answer 10

Symptoms vary over time and in intensity.

Question 11

Acute changes in asthma?

Answer 11

• Smooth muscle contraction
• Mucus hypersecretion
• Oedema
• Plasma leakage
• Sensory nerve activation

Question 12

Chronic changes in asthma?

Answer 12

• Subepithelial fibrosis
• Smooth muscle hypertrophy

Question 13

How is reversibility tested?

Answer 13

Pre- and post-bronchodilator spirometry (400 mcg salbutamol).

Question 14

Positive reversibility criteria?

Answer 14

≥200 mL and ≥12% increase in FEV1.

Question 15

Greater confidence threshold?

Answer 15

≥400 mL and ≥15% increase.

Question 16

Is PEFR effort dependent?

Answer 16

Yes.

Question 17

How long should PEFR be monitored?

Answer 17

2–4 weeks (twice daily in adults).

Question 18

Significant variability in PEFR?

Answer 18

> 10% (GINA) to >20% (NICE).

Question 19

What does bronchial challenge test detect?

Answer 19

Bronchial hyperresponsiveness.

Question 20

Mannitol challenge mechanism?

Answer 20

Triggers inflammatory mediator release → bronchoconstriction.

Question 21

Normal FeNO level?

Answer 21

<25 ppb.

Question 22

High FeNO level?

Answer 22

> 50 ppb.

Question 23

NICE threshold supporting asthma diagnosis?

Answer 23

> 40 ppb.

Question 24

What does high FeNO predict?

Answer 24

Good response to inhaled corticosteroids.

Question 25

Gold standard for airway eosinophilia?

Answer 25

Sputum eosinophils.

Question 26

Role of blood eosinophils in COPD?

Answer 26

Predict response to inhaled steroids.

Question 27

Blood tests for atopy?

Answer 27

Total IgE, specific IgE (RAST).

Question 28

Other test for atopy?

Answer 28

Skin prick testing.

Question 29

Allergic asthma characteristics?

Answer 29

- Childhood onset - eosinophilic inflammation - identifiable triggers.

Question 30

Non-allergic asthma types?

Answer 30

- Eosinophilic - neutrophilic - paucigranulocytic.

Question 31

Asthma with persistent airflow limitation?

Answer 31

Fixed or incompletely reversible obstruction.

Question 32

Asthma and obesity phenotype?

Answer 32

Prominent symptoms, little eosinophilic inflammation.

Question 33

Definition of COPD?

Answer 33

Preventable, treatable disease with persistent symptoms and airflow limitation due to airway/alveolar abnormalities.

Question 34

Main risk factor for COPD?

Answer 34

Smoking.

Question 35

Other COPD risk factors?

Answer 35

- Biofuels - occupation - genetics - chronic asthma - passive smoking.

Question 36

Key pathological features of chronic bronchitis?

Answer 36

* Mucus gland hypertrophy * Goblet cell hyperplasia * Smooth muscle hypertrophy * Inflammation

Question 37

Definition of emphysema?

Answer 37

Abnormal enlargement of distal airspaces with destruction of walls and no fibrosis.

Question 38

Why does emphysema cause obstruction?

Answer 38

Loss of elastic recoil → reduced radial traction → airway collapse.

Question 39

Main mechanism of hypoxia in COPD?

Answer 39

Ventilation-perfusion (V/Q) mismatch.

Question 40

What happens to pulmonary arteries in chronic hypoxia?

Answer 40

Vasoconstriction and remodelling → pulmonary hypertension.

Question 41

What is cor pulmonale?

Answer 41

Right heart failure due to chronic lung disease.

Question 42

What is bronchiectasis?

Answer 42

Permanent abnormal dilatation of bronchi.

Question 43

Main symptoms bronchiectasis?

Answer 43

Chronic purulent sputum, recurrent infections.

Question 44

Gold standard diagnostic test for bronchiectasis?

Answer 44

High-resolution CT (HRCT).

Question 45

Why does bronchiectasis cause airflow obstruction?

Answer 45

Small airway fibrosis and secretions cause narrowing despite bronchial dilatation.

Question 46

Variable obstruction + reversibility + high FeNO = ?

Answer 46

Asthma.

Question 47

Persistent obstruction + smoking history = ?

Answer 47

COPD.

Question 48

Dilated bronchi on HRCT + purulent sputum = ?

Answer 48

Bronchiectasis.

Question 49

Loss of elastic recoil + hyperinflation = ?

Answer 49

Emphysema.

Question 50

Chronic hypoxia → pulmonary hypertension → ?

Answer 50

Cor pulmonale.