L10 - interstitial lung disease

Question 1

obstructive spirometry

Answer 1

lower FEV1 and same FVC

Question 2

Restrictive spirometry

Answer 2

much lower FEV1 and FVC, lower expiratory flow rate

Question 3

measuring ILD

Answer 3

can be seen in x-rays through scarring

Question 4

ILD

Answer 4

disease of gas exchange, increased barrier due to scarring so oxygen must travel further whilst CO2 can still escape therefore less gas exchange

Question 5

lung disunion factor in ILD

Answer 5

reduced for carbon monoxide

Question 6

Incremental shuttle walk test

Answer 6

walking bleep test around 2 cones

Question 7

Six minute walk test

Answer 7

walking continuously around 2 cones for 6 minutes and recording distance walked

Question 8

Resistriction of lung volumes

Answer 8

measured by FVC

Question 9

reduction in lung gas transfer effieicny

Answer 9

Dlco/Tlco

Question 10

Physiology testing

Answer 10

hypoxia in exertion/exercise

reduction in exercise capacity

Question 11

IPD cause

Answer 11

unclear cause, therefore idiopathic

occurs through fibrosis of lung parenchyma

Question 12

IPD mehcnaism

Answer 12

fibroblast repair damaged tissue, migrate to lungs to become myofibroblass which deposit collagen in the extracellular matrix and then proliferate to form fibroblastic foci
the thickened tissue leads to lower gas exchange efficiency int he lungs

Question 13

IPD genetic susceptability

Answer 13

mutations in genes involved in telmere length maintenance

variations in genes responsible for cell adhesion nd integrity
single nucleotide polymorphism in MUC5B promote region

Question 14

IPD Lung microbiome

Answer 14

increased risk of disease progression in patients due to increased overall bacterial burden, abundance of streptococcal and staphylococcal organisms
Risk of IPF is increased by genetic variation in TOLLIP

Question 15

TOLLIP

Answer 15

gene encoding a protein that inhibits responses to microbes

Question 16

Genes in maintenance of telomere length

Answer 16

TERT, TERC, PARN and RETEL1

Question 17

IPD key featues

Answer 17

fibroblasts collections, thickening of alveolar interstitial, destruction of alveoli, periphery and base of lungs affected, spatial heterogeneity

Question 18

Spatial heterogeneity

Answer 18

normal lung tissue next to abnormal lung tissue

Question 19

Hypersensitivity pneumonitis

Answer 19

immune-mediated hypersensitivity reaction in a genetically predisposed individual

Question 20

HP inducers

Answer 20

recurrent exposure to environmental agents

Question 21

HP pathogenesis

Answer 21

very different to IPD

inflammation nd air trapping, may progress to fibrosis and look like UIP pattern on HRCT

Question 22

type I

Answer 22

IgE, rapid onset

e.g. latex allergy and asthma

Question 23

type II

Answer 23

cytotoxic, antibody e.g. acute transplant rejection

Question 24

type III

Answer 24

immune complex deposition (antibody and antigen) e.g. hypersensitivity pneumonitis

Question 25

Type IV

Answer 25

T cell, delayed e.g. chronic transplant rejection

Question 26

HP type

Answer 26

type III

Question 27

HP mechanism

Answer 27

prior sensitisation required, IgG antibodies produced by lymphocytes retain antigen immune memory
on second exposure antigen-antibody complexes are formed and deposit in lungs without being properly cleared

Question 28

Repeated exposure in HP

Answer 28

leads to repeated symptoms and physiological decline

Question 29

HP immunopathological mechanism

Answer 29

associated with increase of CD4+ T cells, CD4/8 ratio and Th2 activity
CD4+ Th17 cells involved in lung fibrosis development
tolerance may be mediated by regulatory T cells

Question 30

CTP-ILD common

Answer 30

System sclerosis, rheumatoid arthritis and idiopathic inflammatory myositis

Question 31

Idiopathic NSIP

Answer 31

up to 15% diagnosed with this are later found to have CTD

Question 32

Interstitial pneumonia with autoimmune features

Answer 32

ILD can occur in presence of autoimmune features that do not meet specific CTD classification

Question 33

CTP-ILD hypothesis

Answer 33

lung injury triggers local inflammation which induces auto-antigen expression causing auto-antibody generation in lung

Question 34

ILD mechanism

Answer 34

unknown triggers cause inflammatory cells to invade interstitial and alveolar spaces
lung epithelial damage
recruitment and activation of moo/fibroblasts
which produce increased amounts of extracellular matrix proteins and populate fibrogenic cell scarring within lung
results in interstitial lung disease

Question 35

Sarcoidosis

Answer 35

granulomatous disease characterised by presence of non-caseating granulomas involving multiple organ systems
lungs affected in over 90% of cases

Question 36

Sarcoidosis cause

Answer 36

exact cause remains unknown but many studies suggest right combination of antigen exposure in a genetically predisposed individual under favourable environmental conditions contributes to disease devleopment

Question 37

sarcoidosis exposures

Answer 37

insecticides, agricultural employment, work environments with mould and occupational areas with musty odours

Question 38

sarcoidosis mechanism

Answer 38

antigen exposure and internalisation, with presentation in regional lymph nodes
CD4+ cell activation, proliferation and Th1 polarisation induced by antigen recognition and co-stimulator signals
Newly-activated circulating CD4+ cells bone, via chemokine, to tissue sites with antigen, and stimulate macrophages to organise into granulomas
chronic inflammation nd pulmonary fibrosis