Diffuse Interstitial Lung Diseases

Front 1

Define pulmonary interstitium

Back 1

Connective tissue
- alveolar septa
- peribronchial tissue
- perivascular tissue

Front 2

What are the aetiologies of acute ILD?

Back 2

1. Lung injuries

2. Systemic injuries

Front 3

give examples of lung injuries causing acute ILD?

Back 3

1. Common (gastric aspiration, viral pneumonitis)

2. Uncommon (toxic fume inhalation, drowning, post-lung tx)

Front 4

give examples of systemic injuries causing acute ILD?

Back 4

1. common (sepsis, shock, severe trauma)

2. uncommon (acute pancreatitis, drug OD)

Front 5

describe the pathogenesis of acute ILD (6)

Back 5

1. injury epithelium, endothelium, or both

2. release inflamm. cytokines (TNFa, IL1b)

3. necrosis of alveolar wall (pneumocytes, endo.)

4. loss of alveolar surfactant, capillary leak

5. air space collapses

6. ventilation/perfusion mismatch

Front 6

what are the physiological effects in acute ILD? (5)

Back 6

when diffuse, leads to pulmonary function impairment.

1. reduced lung compliance (increased stiffness, impaired DL)

2. VQ mismatch (severely impaired GE)

Front 7

Contrast mild acute ILD and severe acute ILD

Back 7

Mild disease is interstitial pneumonitis (e.g. viral pneumonitis)

Severe disease is diffuse damage, or life-threatening diffuse alveolar damage

Front 8

What is the PG of acute interstitial pneumonitis e.g. severe viral infections?

Back 8

1. inhale infectious agents (virus, rickettsia, chlamydia, mycoplasma)

2. damage alveolar wall (pneumocytes, endothelium, interstitial cells, lymphocyte infiltration)

Front 9

What is DAD?

b) mortality

c) what happens to surviving patients?

Back 9

acute, rapidly deteriorating RF, severe hypoxemia (ARDS)

b) 30-40%

c) recover fully; or lung fibrosis

Front 10

What happens in DAD? (7)

Back 10

1. alveolar wall necrosis
2. oedema
3. escape of RBC
4. leakage of serum protein
5. hyaline membrane formed by fibrinous exudate and cell debris
6. loss of surfactant (surface tension increased)
7. poor lung expansion (alveolar collapse)

Front 11

what is chronic ILD?

b) what is it caused by?

c) what may it result in?

Back 11

group of heterogeneous diseases causing extensive injury to lung interstitium

b) chronic inflamm, fibrosis of lung w. functional impairment

c) recurrent or continuous lung damage (initial injury may/may not be noticed)

Front 12

what are the etiologies of chronic ILD?

Back 12

1. toxic damages (toxic fume, irradiation, cytotoxic drugs, prolonged tx w. hyperbaric O2)

2. mineral dust deposition (pneumoconiosis)

3. auto-immune diseases (systemic sclerosis, SLE)

4. others (sarcoidosis, allergic condition like extrinsic allergic alveolitis)

Front 13

give 2 examples of chronic interstiital lung disease

Back 13

1. idiopathic pulmnary fibrosis/cryptogenic fibrosing alveolitis

2. pneuconiosis (due to mineral dust deposition0

Front 14

What is idiopathic pulmonary fibrosis/cryptogenic fibrosing alveolitis?

Back 14

chronic and ultimately fatal disease characterized by a progressive decline in lung function. The term pulmonary fibrosis means scarring of lung tissue and is the cause of worsening dyspnea

Front 15

Idiopathic interstitial pneumonitis:
a) Cause

b) Characteristic patterns?

Back 15

a) unknown and heterogeneous

b) Bronchiolitis obliterans organizing pneumonia

Front 16

what is BOOP?

Back 16

bronchiolitis obliterans organizing pneumonia:
proliferation of young fibroblasts into small bronchioles and alveolar spaces

Front 17

Describe the pathogenesis of IPF (3)

Back 17

1. a diffuse insult (lung injury)

2. activate B, T and macrophage: causes chronic inflammation - persistent and chronic damage;

3. interstitial inflammation of variable severity
Injury to type 1 pneumocytes, hyperplasia and hypertrophy of type II pneumocytes)
bronchiolar epithelium extends to line airspaces

Front 18

what happens in end stage disease of IPF? (2)

Back 18

honeycomb lung:
1. acini are simplified -> cystic spaces
2. bronchiolar epithelium grows into cystic spaces

Front 19

what are the pathological features of IPF? (4)

Back 19

1. interstitial fibrosis
2. obliteration of some air spaces
3. cystic dilatation of other air spaces
4. chronic inflamm cells (but not always present)

Front 20

What is the macroscope appearance of IPF? (2)

Back 20

1. thickened alveolar wall. rigid shrunken lung (restrictive pattern)

2. honeycomb lung (end-stage changes)

Front 21

How does each tissue reaction affect lung function:
1. fibrosis tissues (3)
2. decrease capillaries (2)
3. alveolar wall fibrosis (3)

Back 21

1. decrease compliance, increase elastic recoil. this causes restrictive lung function and stiff rigid lungs.

2. decrease gas exchange and impairs perfusion

3. decrease SA and diffusion capacity. reduces ventilation and cause V/P mismatch.

Front 22

what are the clinical features of end-stage diffuse ILD? (7)

Back 22

1. impaired GE (SOB, no wheeze)
2. chronic hypoxia
3. dry cough
4. coarse lines and nodules on CXR
5. increase risk of lung cancer
6. severe cases die within several years

Front 23

what is diagnosis of ILD based on? (5)

Back 23

1. History and relevant tests

2. clinical features (restrictive lung function pattern)

3. radiological features (interstitial thickening, distribution pattern)

4. pathological (tissue reaction pattern)

5. Tissue exam: assess disease activity (active inflammation? fibrosis? asbestos bodies?)

NB if no cause -> IPF`

Front 24

what is pneumoconiosis?

b) what determines its presentation? (2)

c) what history must you obtain from px?

Back 24

lung fibrosis due to inhalation of inorganic dusts.

b)
1. dust: chemical nature, physical state and particle size (determines chronic inflammation)
2. duration and concentration of exposure

c) occupation (it may be occupation disease -> compensatable)

Front 25

what is silicosis

Back 25

ILD after prolonged (>10-20 years) or massive exposure to silica (SiO2)

Front 26

where can you contact silica?
(give 3 examples)

Back 26

major component of earth's crust

quartz-mining, rock-cutting, glass-making, pottery, sand-blasting

Front 27

what is the pathologic feature of silicosis? (3)

Back 27

silicotic nodules:
1. interstitial macrophage releases fibrogenic factors
2. fibroblasts produce collagen
3. lymphocytes collect

Front 28

what can silicosis lead to? (3)

Back 28

advanced silicosis leads to:
- honeycomb lung
- respiratory failure
- cor pulmonale

Front 29

what is asbestos? (2)

b) what is it used in?

Back 29

fibrous magnesium silicate,
long thin fibers that are curved OR straight

b) fire-resistant, acoustic and thermal insulator

Front 30

what is asbestosis?

b) how does it develop? (3)

Back 30

diffuse interstitial fibrosis developing after prolonged or heavy exposure.

b)
1. prolonged or heavy exposure to asbestos fibres
2. interstitial macrophages ingest fibres
3. fibroblasts collect outside the distal air space releasing collagen (interstitial fibrosis)

Front 31

what is the hallmark of asbestos exposure? (2)

Back 31

Asbestos bodies:
1. long, beaded brownish in bronchial fluids and sputum.
2. asbestos fibers covered by a film of protein impregnated with haemosiderin.

Front 32

what are asbestos-related conditions? (2)

Back 32

1. lung cancer ~ higher risk in smokers

2. malignant mesothelioma (from mesothelium or lining of pleura, pericardium, peritoneum).
AGGRESSIVE TUMOUR!

Front 33

what is pulmonary vasoconstriction? (2)

Back 33

1. increase in fibroblasts and SM cells
-> obliterates vessel lumen

2. thickening of tunica intima and media

Front 34

what does it cause? (3)

Back 34

1. chronic hypoxia

2. reduced vascular channels (increase vascular resistance)

3. Pulmonary HT (systolic BP > 30 mmHg)
cor pulmonale (right heart failure)

Front 35

what is the difference between early and late p. vasoconstriction?

Back 35

early - reversible constriction
late - structural change, irreversible

Front 36

what are the signs of chronic hypoxia? (3)

Back 36

1. right ventricular hypertrophy and dilatation (from primary diseases affecting function/structure of lung and its vessels - excluding diseases of left heart and congenital heart disease)

2. right heart failure (systemic venous congestion)

3. increased RBC (polycythaemia, increased viscosity) to compensate for decrease in PaO2

Front 37

what are the acute forms of ILD? (2)

Back 37

interstitial pneumonitis, DAD

Front 38

1. what are the causes of chronic ILD?

2. what is the outcome of chronic ILD?

Back 38

1. heterogeneous

2. same end-stage of diffuse interstitial fibrosis, with similar functional impairment and clinical features