Restrictive Lung Diseases

Question 1

Define restrictive lung disease and how it differs from obstructive lung disease.

Answer 1

✅ Answer:
Restrictive lung disease is characterized by reduced total lung capacity with relatively normal expiratory flow. Causes include:

Reduced chest wall movement (e.g., obesity, paralysis)

Interstitial lung diseases (e.g., pneumoconioses)

Infiltrative diseases (e.g., pneumonitis)

Question 2

What types of particles cause pneumoconioses and what is their typical size?

Answer 2

✅ Answer:

Caused by inhalation of 1–5 µm particles (e.g., coal dust, silica, asbestos)

Large particles (>10 µm) are cleared nasally

Small particles (<1 µm) are often exhaled

1–5 µm particles reach alveoli and trigger disease

Question 3

Describe the general pathogenesis of pneumoconiosis.

Answer 3

✅ Answer:

Inhalation of dust particles (1–5 µm)

Engulfed by alveolar macrophages

Attempted clearance via lymphatics

Macrophages die en route, triggering chronic inflammation

Fibrosis and scarring develop, reducing lung function

Question 3

How does the pathology of silicosis differ from CWP?

Answer 3

✅ Answer:

Site: Mid-lobule/alveolar junctions

Scars: Large, onion-skin layered collagen bundles

More severe than CWP

Leads to panlobular emphysema

Question 3

Where is the primary site of inflammation in CWP, and what are the histological features?

Answer 3

✅ Answer:

Site: Terminal bronchioles (proximal)

Features:

Stellate (star-shaped) scars

Centrilobular emphysema

Carbon-laden macrophages

Mild loss of function

Question 4

What vascular complication can arise from CWP and why?

Answer 4

✅ Answer:
Pulmonary hypertension due to:

Fibrotic scars compressing blood vessels

Impaired vasodilation and increased vascular resistance

Question 4

What unique microscopy technique helps identify silica particles?

Answer 4

✅ Answer:
Polarised light microscopy shows silica crystals as shimmering, star-like particles under rotation.

Question 4

Why does silicosis increase TB susceptibility?

Answer 4

✅ Answer:
Silica impairs macrophage function and antigen presentation, weakening immune response against mycobacterial infections.

Question 5

What makes asbestos fibres particularly harmful?

Answer 5

✅ Answer:

Long, thin fibres (∼100 µm) can’t be phagocytosed by single macrophages

Persist in alveoli → form foreign body giant cells

Induce diffuse fibrosis and inflammation

Highly carcinogenic, especially with smoking

Question 6

What histological features define asbestosis?

Answer 6

✅ Answer:

Diffuse, patchy fibrosis (no onion-skin or stellate pattern)

Ferruginous bodies (asbestos cores coated with hemosiderin)

Giant cells, extravasated RBCs

Pleural adhesions and massive functional loss

Question 7

Compare CWP, silicosis, and asbestosis.
Inflammation site/ Scarring pattern / Functional loss /Cancer risk

Answer 7

CWP : Terminal bronchioles, Stellate, Mild, Low

Silicosis: Mid-lobule, Onion-skin, Moderate, Moderate (TB risk)

Asbestosis: Alveoli, Diffuse & patchy, Severe, High (mesothelioma)

Question 8

List three complications common across all pneumoconioses.

Answer 8

✅ Answer:

Fibrosis → restrictive lung disease

Pulmonary hypertension

Recurrent infections (e.g., bacterial pneumonia)

Question 9

What cancer is uniquely associated with asbestosis?

Answer 9

✅ Answer:
Mesothelioma, a rare, aggressive cancer of the pleura, strongly linked to asbestos exposure, worsened by smoking.

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