Obstructive vs Restrictive Lung Disease

Obstructive = difficulty exhaling (↓FEV1/FVC), Restrictive = difficulty inhaling (normal or ↑FEV1/FVC with ↓total volumes).

Detailed Explanation

Obstructive Lung Diseases:

COPD (emphysema, chronic bronchitis)

Asthma

Bronchiectasis

Spirometry Pattern:

↓ FEV1

↓ or normal FVC

↓ FEV1/FVC ratio (<70% or <0.7)

↑ TLC, ↑ RV (air trapping)

Restrictive Lung Diseases:

Pulmonary fibrosis (IPF)

Pneumoconioses

Sarcoidosis

Chest wall disorders

Neuromuscular disease

Spirometry Pattern:

↓ FEV1

↓ FVC (more than FEV1)

Normal or ↑ FEV1/FVC ratio (>80%)

↓ TLC

Key Distinction:

FEV1/FVC < 0.7 = Obstructive

FEV1/FVC normal/high + ↓TLC = Restrictive

Clinical Correlation

A 65-year-old smoker with barrel chest and prolonged expiration has obstructive disease (COPD). A construction worker with progressive dyspnea and ground-glass opacities on CT likely has restrictive disease (asbestosis, silicosis).

Memory Trick

"Obstructive = can't get air OUT (like blowing through a straw). Restrictive = can't get air IN (like breathing with a tight corset)."