Questions: COPD: Emphysema and Chronic Bronchitis

Question 1

A patient with advanced emphysema uses pursed-lip breathing during exhalation. Which of the following best explains why this behavioral adaptation develops?

• A. It reduces the work of inhalation by relaxing accessory muscles during each breath cycle
• B. It creates back-pressure that splints open small airways, compensating for the loss of elastic recoil
• C. It increases the FEV₁/FVC ratio by slowing forced expiratory flow to normal levels
• D. It drives more oxygen into alveoli by increasing airway resistance upstream

Answer: (B)

Without elastic recoil, small airways collapse during exhalation and trap air. Pursed-lip breathing creates auto-PEEP — positive end-expiratory back-pressure that keeps small airways open long enough to allow more complete exhalation. It is a mechanical compensation for the lost recoil, not a technique for improving inhalation.

Question 2

A patient diagnosed with COPD quits smoking after 30 years. What is the most accurate prediction about the course of their disease?

• A. Lung function will gradually recover over 5–10 years as alveolar walls slowly regenerate
• B. Smoking cessation is largely cosmetic — disease progression continues at the same rate regardless
• C. The accelerated FEV₁ decline will slow toward the normal age-related rate, but destroyed alveolar tissue will not regenerate
• D. The chronic bronchitis component will permanently resolve, but the emphysema component will worsen without the inflammatory stimulus

Answer: (C)

Smoking cessation halts the abnormal acceleration of FEV₁ decline — patients will lose lung function at the normal age-related rate rather than the faster COPD rate. But alveolar destruction from the protease-antiprotease imbalance is irreversible; structural changes do not reverse. This distinction between halting damage and reversing it is clinically critical.

Question 3

Dyspnea in emphysema is primarily a mechanical problem — the hyperinflated chest and flattened diaphragm put respiratory muscles at a disadvantage — rather than primarily a failure of gas exchange.

• T. True
• F. False

Answer: True

Loss of elastic recoil causes air trapping and hyperinflation, which flattens the diaphragm (reducing its mechanical advantage) and forces the patient to breathe at high lung volumes using accessory muscles. This mechanical disadvantage is the primary driver of dyspnea, especially early in the disease when gas exchange may still be relatively preserved.

Question 4

Chronic bronchitis is defined pathologically by mucus gland hypertrophy and goblet cell metaplasia visible on biopsy.

• T. True
• F. False

Answer: False

Chronic bronchitis is defined clinically — specifically as a productive cough for at least three months in each of two consecutive years in a patient without other explanatory conditions. While mucus gland hypertrophy (reflected in the Reid index) and goblet cell metaplasia are observed histologically, the diagnosis is made on clinical criteria. Pathological changes may be present without meeting the clinical definition.

Question 5

Explain why emphysema and chronic bronchitis both reduce airflow but through fundamentally different mechanisms.

Model answer: In emphysema, alveolar walls are destroyed by protease activity, eliminating the elastic recoil that normally drives passive exhalation. Without recoil, small airways collapse during exhalation and trap air — obstruction from the outside in, from lost driving force. In chronic bronchitis, chronic inflammation causes mucus gland hypertrophy, goblet cell metaplasia, and airway wall edema that narrow the lumen from the inside, creating intrinsic obstruction. Emphysema is a problem of lost driving pressure; chronic bronchitis is a problem of increased resistance.

Both result in a reduced FEV₁/FVC ratio on spirometry, but the pathophysiology is distinct. This matters for understanding symptoms ('pink puffer' dyspnea vs. 'blue bloater' productive cough and hypercapnia), and for recognizing why treatments must often address both mechanisms in patients with mixed COPD.