Restrictive lung disease

Question 1

What is a restrictive lung disease?

Answer 1

Where lung volume is lower due to restriction of expansion of the lung due to either intrinsic or extrinsic disorders

Question 2

What are intrinsic lung diseases?

Answer 2

Alterations to the lung parenchyma

Question 3

What are extrinsic lung diseases?

Answer 3

Disorders that compress the lungs or limit expansion, can be pleural, chest wall related or neuromuscular

Question 4

What is the lung parenchyma?

Answer 4

The alveolar regions of the lung

Question 5

What are the important cellular components of the lung parenchyma?

Answer 5

Alveolar type 1 and 2 epithelial cells, fibroblasts, alveolar macrophages and the interstitial space

Question 6

What is the function of alveolar type 1 cells?

Answer 6

The gas exchange surface

Question 7

What is the function of alveolar type 2 cells?

Answer 7

Surfactant to reduce surface tension, stem cells for repair

Question 8

What is the function lung parenchyma fibroblasts?

Answer 8

Produce ECM

Question 9

What is the function of alveolar macrophages?

Answer 9

Phagocytise foreign material, surfactant

Question 10

What is the lung parenchyma interstitial space?

Answer 10

Space between the alveolar epithelium and capillary endothelium

Question 11

What does the lung parenchyma interstitial space contain and what is its function?

Answer 11

Contains lymphatic vessels, fibroblasts and ECM. Provides structural support to the lung and is very thin to facilitate gas exchange

Question 12

What are the six classifications of interstitial lung diseases (ILD)?

Answer 12

Idiopathic, autoimmune related, exposure related, those with cysts or airspace filling, sarcoidosis and others

Question 13

Different patterns of fibrosis influence survival of ILD, which pattern decreases survival the most?

Answer 13

UIP

Question 14

What are the signs and symptoms associated with ILD?

Answer 14

Progressive breathlessness, non-productive cough, limitation in exercise tolerance, occupational and exposure history, medication history (drug induced ILD) and family history of ILD ( up to 20% of idiopathic ILDs are familial)

Question 15

What is found on clinical examination of a patient with ILD?

Answer 15

Low oxygen saturations, fine bilateral inspiratory crackles, digital clubbing

Question 16

What investigations are undertaken to diagnose ILD?

Answer 16

Blood tests, pulmonary function tests, 6 minute walking test, high resolution CT scan, invasive testing - bronchoalveolar lavage (BAL), surgical lung biopsy

Question 17

What parameters are looked at in diagnostic blood testing for ILD?

Answer 17

Anti-nuclear antibody, rheumatoid factor, anti-citrullinated peptide (CCP)

Question 18

Outline the physiology of ILD

Answer 18

Scarring makes lung stiff decreasing compliance, decreasing lung volume, decreasing diffusing capacity of lung for carbon monoxide, lowering arterial PO2

Question 19

What is the expected FEV1:FVC ratio of a patient with ILD?

Answer 19

Normal or raised

Question 20

What is idiopathic pulmonary fibrosis (IPF)?

Answer 20

Progressive scarring lung disease of unknown cause,

Question 21

What is the average decline in forced vital capacity (FVC) associated with IPF?

Answer 21

150-200mls per year

Question 22

What are the proposed mechanisms of IPF?

Answer 22

Predisposing factors such as genetic susceptibility, environmental triggers and cellular ageing

Question 23

What are the characteristic features of IPF on a CT scan?

Answer 23

Subpleural honeycombing and traction bronchiectasis. Basal predominance in coronal plane

Question 24

Is immunusupression used to treat IPF?

Answer 24

No, has been shown to be harmful

Question 25

What treatment is given to slow disease progression in IPF

Answer 25

Antifibrotics

Question 26

What is hypersensitivity pneumonitis?

Answer 26

ILD caused by immune-mediated response in susceptible and sensitised individuals to inhaled environmental antigens, involves the small airways and parenchyma

Question 27

What are the two classifications of HP and how are they different?

Answer 27

Acute HP - intermittent, high level exposure, abrupt symptom onset, flu-like syndrome
Chronic HP - long-term, low-level exposure, is either non-fibrotic or fibrotic

Question 28

Which type of chronic HP has the higher mortality?

Answer 28

Fibrotic

Question 29

Outline how immunological dysregulation drives HP

Answer 29

Antigen exposure and processing by the innate immune system causes an inflammatory response mediated by T-helper cells and antigen-specific immunoglobulin antibodies. This leads to accumulation of lymphocytes and formation of granulomas

Question 30

What will be heard on auscultation of a patient with HP?

Answer 30

Inspiratory ‘squeaks’ caused by the coexisting bronchiolitis

Question 31

How is HP treated?

Answer 31

Complete antigen removal/ avoidance, corticosteroids, immunosuppressants

Question 32

What is systemic sclerosis associated ILD

Answer 32

Autoimmune connective tissue disease characterised by immune dyes regulation and progressive fibrosis that affects the skin, with variable internal organ involvement

Question 33

How is SSc associated ILD classified?

Answer 33

Based on skin involvement: can be limited cutaneous SSc or diffuse cutaneous SSc

Question 34

Limited cutaneous SSc is more associated with _____, whereas diffuse cutaneous SSc is more commonly associated with _______

Answer 34

Limited cutaneous more associated with pulmonary hypertension whereas diffuse cutaneous SSc more associated with ILD

Question 35

What is the most common type of ILD?

Answer 35

IPF