Interstitial Lung Disease

Question 1

What is interstitial lung disease?

Answer 1

A group of >200 lung diseases characterised by inflammation and fibrosis of the pulmonary connective tissue, particularly the interstitium of the alveolar wall

Question 2

Describe the features of interstitial lung disease on spirometry

Answer 2

Restrictive pattern: decreased CO diffusion capacity, decreased lung volume, decreased compliance

Question 3

How does interstitial lung disease present?

Answer 3

Dyspnoea, end-inspiratory crackles, cyanosis, pulmonary hypertension, cor pulmonale

Question 4

Describe the histological features of end-stage interstitial lung disease

Answer 4

Honeycomb lung - variably sized cysts in a background of densely scarred lung tissue. Enlarged airspaces surrounded by fibrosis with hyperplastic or bronchiolar type epithelium

Question 5

Name the four categories of interstitial lung disease

Answer 5

Fibrosing, granulomatous, eosinophilic, smoking-related

Question 6

State at least 4 causes of fibrosing interstitial lung disease

Answer 6

Cryptogenic fibrosing alveolitis (idiopathic), pneumoconiosis, cryptogenic organising pneumonia, connective tissue disease, drug-induced, radiation pneumonitis

Question 7

State 3 causes of granulomatous interstitial lung disease

Answer 7

Sarcoid, extrinsic allergic alveolitis, vasculitides

Question 8

Is cryptogenic fibrosing alveolitis more common in males or females?

Answer 8

Male

Question 9

Describe the histological features of cryptogenic fibrosing alveolitis

Answer 9

Progressive patchy interstitial fibrosis with loss of normal lung architecture and honeycomb change, beginning at the periphery of the lobule, usually sub-pleural. Hyperplasia of type II pneumocytes causing cyst formation (honeycomb fibrosis)

Question 10

Describe the clinical features of cryptogenic fibrosing alveolitis

Answer 10

Increasing exertional dyspnoea and non-productive cough in a 40-70 year old, with hypoxaemia, cyanosis, and pulmonary hypertension with or without cor pulmonale and clubbing

Question 11

How is cryptogenic fibrosing alveolitis managed?

Answer 11

Steroids, cyclophosphamide, azathioprine (little impact on survival)

Question 12

What is pneumoconiosis?

Answer 12

A non-neoplastic lung reaction to inhalation of mineral dusts or inorganic particles. Usually affects the upper lobe

Question 13

Name three pneumoconioses

Answer 13

Coal workers pneumoconiosis, silicosis, asbestosis

Question 14

Define BOOP

Answer 14

Bronchiolitis obliterans organising pneumonia, also known as cryptogenic organising pneumonia

Question 15

Which lobe of the lung does asbestosis tend to affect?

Answer 15

Lower lobe

Question 16

What is a granuloma?

Answer 16

Collection of histiocytes, macrophages, and multinucleate giant cells

Question 17

Name at least 4 granulomatous infections

Answer 17

TB, histoplasma, Cryptococcus, coccidioides, aspergillus, mucor, pneumocystis

Question 18

What is extrinsic allergic alveolitis?

Answer 18

An immune-mediated lung disorder causes by prolonged or intense exposure to inhaled organic antigens producing widespread alveolar inflammation

Question 19

Describe the histological features of extrinsic allergic alveolitis

Answer 19

Granuloma formation and organising pneumonia - presence of polypoid plugs of loose connective tissue within alveoli

Question 20

Describe the clinical features of acute extrinsic allergic alveolitis/ hypersensitivity pneumonitis

Answer 20

Fever, chills, dyspnoea, cough within hours of exposure to the antigen, usually settling by the following day

Question 21

Describe the clinical features of chronic extrinsic allergic alveolitis

Answer 21

Progressive persistent productive cough, dyspnoea, finger clubbing, severe weight loss

Question 22

State at least 3 examples of chronic extrinsic allergic alveolitis

Answer 22

Farmers lung (Saccharopolyspora rectivirgula in mouldy grain), Pigeon fancier’s lung (proteins in pigeon excreta and feathers), Humidifer’s lung (Thermatinomyces species in heated water reservoirs), Malt-workers lung (Asperigillus clavatus or fumigatus in germinating barley), Cheese washer’s lung (Aspergillus clavatus or penicillium casei in mouldy cheese)