restrictive lung disease

Question 1

in restrictive lung disease, what is the lung volume

Answer 1

small

Question 2

examples of extrinsic disorders

Answer 2

compress lungs or limit expansion
-Pleural
-Chest wall

Question 3

what is an example of Intrinsic lung disease

Answer 3

alterations to lung parenchyma

interstitial lung disease (ILD)

Question 4

what is lung parenchyma

Answer 4

alveolar region of lung

Question 5

what is Interstitial space

Answer 5

space between alveolar epithelium and capillary endothelium.

-lymphatic vessels, fibroblasts, ECM.
-Structural support to lung
-Very thin for gas exchange

Question 6

what is Alveolar type 2 epithelial cell

Answer 6

surfactant to reduce surface tension, stem cell for repair

Question 7

what is Alveolar type 1 epithelial cell

Answer 7

gas exchange surface

Question 8

what is Fibroblasts

Answer 8

produce ECM e.g Collagen type 1

Question 9

some types of interstitial lung disease

Answer 9

idiopathic-idiopathic pulmonary fibrosis

auto-immune related- systemic sclerosis

exposure related-hypersensitivity pneumonitis

with cysts/airspace filling

sarcoidosis

Question 10

Investigations in ILD

Answer 10

-Blood tests e.g. (ANA), (RhF), (CCP)
-6-minute walk test
-High resolution CT scan
-invasive= surg-lung biopsy

Question 11

Lung physiology in ILD- what is?
-Lung volumes (TLC, FRC, RV),
-FVC,
-diffusing capacity of lung for carbon monoxide (DLCO),
-arterial PO2
-FEV1/ FVC ratio

Answer 11

↓ Lung volumes (TLC, FRC, RV)

↓ FVC

↓ diffusing capacity of lung for carbon monoxide (DLCO)

↓ arterial PO2 – particularly with exercise

Normal or ↑ FEV1/ FVC ratio (0.8+)

Question 12

what can be seen in [usual interstitial pneumonia] - HRCT vs histopathology

Answer 12

usually in IPF:
HRCT:
honeycombing on peripheral/base of lungs

Histopathology- microscopic honeycomb cyst +
fibroblastic foci-> proliferating fibroblast= active disease

Question 13

what can be seen in [organising pneumonia]

Answer 13

ground glass opacities- alveoli filled with a bit of fluid

consolidation- alveoli completely filled with fluid

Question 14

what are the proposed predisposing factors for IPF

Answer 14

Genetic susceptibility
-MUC5B, DSP

Environmental triggers
-smoke, viruses, pollutants, dusts

Cellular ageing
-telomere attrition, senescence

Question 15

pathology pathway for IPF

Answer 15

1. alveoli injury
2. profibrotic macrophage/fibroblast produce a lot of ECM-> accumulates.
3. remodelling + honeycomb cyst form
4. interstitial thickens, gas exchange not as effective

Question 16

what can be seen in IPF on CT- in relation to bronchi

Answer 16

traction bronchiectasis = bronchi widening/dilating

Question 17

what should you NOT prescribe in IPF and why

Answer 17

Immunosuppressants - ie. prednisone + azathioprine +N-acetylcysteine

increase risk of death

Question 18

IPF treatment

Answer 18

antifibrotics
-nintedanib - tyrosine kinase inhibitor

-pirfenidone

Question 19

what is hypersensitivity pneumonitis and where it involves

Answer 19

immune- mediated response in sensitised individuals to inhaled environmental antigens (ie. bird droppings)

small airways and parenchyma

Question 20

what are the 2 types of HP and what are they

Answer 20

Acute HP -
-Intermittent, high exposure.
-Sudden onset, flu-like syndrome 4-12 hrs after exposure
-ie. holiday- contact with animal faecels

Chronic HP -
-Long-term, low-level exposure
-Nonfibrotic (purely inflammatory)
-Fibrotic – associated with higher mortality
-ie. bird keeper

Question 21

explain the immunological dysregulation behind hypersensitivity pneumonitis

Answer 21

1.Antigen exposure

2.innate immune system
Inflammatory response mediated by T-helper cells and Ig-G antibodies

3.Accumulation of lymphocytes and formation of granulomas

Question 22

how to diagnose HP

Answer 22

-hx
-inspiratory squeaks- from bronchiolitis
-IgG antibodies
-HRCT- air trapping/ground -glass nodules
-bronchoalveolar lavage lymphocyte count 30%+

Question 23

-HRCT- air trapping/ground -glass nodules - what are the cause in HP

Answer 23

ground glass= interstitial inflammation

air-trapping= narrowing of small airways

Question 24

HP treatment

Answer 24

-antigen removal
-corticosteroids
-immunosuppressants- but poor evidence based
-progressive-> fibrotic HP= nintedanib (antifibrotic)

Question 25

Systemic sclerosis associated ILD- What it is ? more common in?

Answer 25

autoimmune connective tissue disease -> immune dysregulation and progressive fibrosis affects skin + internal organ

young women

Question 26

Systemic sclerosis associated ILD- the 2 types, what is more common in? and antibodies suggesting diagnosis?
where are symptoms normally seen

Answer 26

limited cutaneous SSc- pulmonary hypertension
->Anti-centromere
-face and distal limb

diffuse cutaneous SSc- ILD
->Anti-Scl-70
-trunk+ proximal limb

Question 27

clinical features of SSc

Answer 27

CREST syndrome
calcinosis
raynaud’s phenomenon
esophageal dysfunction
sclerodactyly
telengectasias

+ digital ulcers

Question 28

pathogenesis of SSc-ILD

Answer 28

1. tissue injury/vascular injury/autoimmunity
2. fibrosis
3. inflammation

Question 29

HRCT in SSc-ILD

Answer 29

non-specific interstitial pneumonia pattern- peripheries are generally fine. opacities are more central

Question 30

SSc-ILD management

Answer 30

monitor-HRCT every 3-6m

Corticosteroid risk of renal crisis with high doses

Immunosuppressives – cyclophosphamide, mycophenolate mofetil

Progressive fibrotic phenotype– Nintedanib (antifibrotic)