Obstructive Airway Disease (OAD)

Obstructive Airway Disease (OAD): Clinical Reference

Obstructive Airway Disease

Air Trapping & Expiratory Limitation

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Interactive Study:
Definition
Disorders where airway resistance increases, making it difficult to exhale fully, leading to air trapping.
Common Types

Asthma

Reversible obstruction, bronchial hyperresponsiveness, eosinophilic inflammation.

COPD

Progressive, irreversible; includes chronic bronchitis and emphysema (alveolar destruction).

Bronchiectasis

Permanent dilatation of bronchi; chronic productive cough, recurrent infections.

Diagnostics
Spirometry
↓ FEV1/FVC (< 0.7), ↑ RV (Residual Volume), ↑ TLC.
CXR
Hyperinflation, flattened diaphragms (esp. emphysema).
Pathophysiology
  • Inflammation: Mucus plugging (Asthma, Chronic Bronchitis).
  • Elastic Recoil Loss: Airway collapse during expiration (Emphysema).
  • Structural: CFTR mutations in Cystic Fibrosis → thick mucus.
High-Yield Pearls

• Reversibility with bronchodilators is the hallmark of Asthma.

Barrel chest results from chronic hyperinflation.

• Pursed-lip breathing increases airway pressure to prevent collapse.

1. What is the defining spirometry ratio for obstructive lung disease?

Answer: FEV1/FVC < 0.7 (or < 70%).

2. Which OAD is characterized by "permanent dilatation" of the bronchi?

Answer: Bronchiectasis.

3. What happens to Residual Volume (RV) in obstructive disease?

Answer: It increases (↑ RV) due to air trapping.

4. Which specific condition involves alveolar wall destruction and loss of elastic recoil?

Answer: Emphysema.

5. Defining criteria for chronic bronchitis: Productive cough for ___ months over ___ years.

Answer: 3 months / 2 consecutive years.

6. In Asthma, which inflammatory cell type is classically elevated?

Answer: Eosinophils.

7. What genetic mutation leads to thick mucus and OAD in Cystic Fibrosis?

Answer: CFTR (Cystic Fibrosis Transmembrane Conductance Regulator).

8. Why do patients with OAD use "pursed-lip breathing"?

Answer: To create back-pressure and keep small airways open during exhalation.

9. What finding on CXR suggests severe emphysema?

Answer: Flattened diaphragms and hyperinflated (lucent) lung fields.

10. True or False: COPD airway obstruction is typically reversible with bronchodilators.

Answer: False (It is progressive and largely irreversible).

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