Diffuse Lung Disease

Question 1

What is diffuse lung disease?

Answer 1

Not a disease per se; refers to lung conditions featuring dyspnoea, cough and a CXR showing diffuse lung involvement.

Question 2

What distinguishes diffuse lung disease from other lung disease patterns?

Answer 2

Diffuse disease generally involve either of both of the alveoli or the interstitium (inc pulmonary vasculature).

Question 3

What makes up the interstitium of the lung?

Answer 3

• Alveolar lining cell
• Epithelial basement membrane (CT w/ passing and fixed cell populations, fluid)
• Endothelial basement membrane
• Endothelial lining cell

Question 4

What processes can cause a diffuse lung pattern acutely?

Answer 4

• Water: altered Starling forces in pulmonary oedema
• Inflammation: actue inhalation injury, acute drug toxicity; acute infection
• Blood: diffuse leakage from inflamed vessels in vasculitits

Question 5

What are the physiological effects of acute diffuse lung disease?

Answer 5

-Stiff lungs
-Tachypnoea
-Cough
-Increased WOB
-Usually severe dyspnoea
Severe VQ impairment -> pts generally hypoxic.

Question 6

What are the causes of subacute or chronic interstitial lung disease?

Answer 6

• IPF
• Sarcoidosis
• Occupational (pneumoconiosis)
• Extrinsic allergic alveolitis
• Drugs
• Radiotherapy
• Pulmonary fibrosis ass/w CT disease
• Vasculitis

Question 7

Ix in diffuse lung disease?

Answer 7

• RFTs
• HRCT
• Blood tests (systemic illness and CT disease)
• Echo
• Lung biopsy (if required)

Question 8

Findings of RFTs in diffuse lung diseases?

Answer 8

• Restrictive (reduced VC, normal FEV1/FVC).

- CO diffusion markedly reduced (indicative of v impaired gas exchange)

Question 9

How does alveolar opacity appear on CXR?

Answer 9

Fluffy, cotton wool like opacity.

Question 10

What are the basic interstitial lung patterns?

Answer 10

1) Linear: septal lines = Kerley lines
2) Reticular: mesh like appearance with lines in all directions
3) Nodular: discrete opacities
4) Reticulonodular: combination of the above

Question 11

What are the most common malignancies producing a nodular interstitial pattern in the lung?

Answer 11

• Thyroid
• Breast
• Renal cell carcinoma

Question 12

What are the major categories for the differential diagnoses of interstitial opacity of nodular pattern?

Answer 12

• Nodular mets
• Nodular pneumoconioses
• Granulomatous diseases

Question 13

Drugs precipitating ILD?

Answer 13

• Methotrexate
• Amiodarone
• Bleomycin
• Busulphan
• Cyclophosphamide
• Nitrofurantoin