Lecture 11.0 - Restrictive Lung Disease Notes Flashcards

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1
Q

Name the 2 sites where the causes of interstitial fibrosis mostly occur in the lung

A
  1. At the lower lung
  2. Sparing of the lower lung/lung bases (occur not in these regions)
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2
Q

Name the causes of interstitial fibrosis occuring at the lower lung

A
  1. Organising DAD
  2. Acute interstitial fibrosis (Hamman-Rich)
  3. Chronic idiopathic pulmonary fibrosis:
    a.Primary
    b.Secondary - ie with systemic disease (ie rheumatoid arthritis, systemic sclerosis)
  4. Chronic oedema
  5. Asbestosis
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3
Q

Name the causes of interstitial fibrosis sparing the lower lung

A
  1. Sarcoidosis
  2. Extrinsic allergic alveolitis /
    hypersensitivity pneumonia
  3. Silicosis
  4. Chronic berylliosis
  5. Infections with a granulomatous pattern
    (may involve the whole lung, ie TB)
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4
Q

What are the 2 clinical presentations of DAD?

A
  • Hypoxia (low oxygen levels)
  • Bilateral lung opacities on chest imaging
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4
Q

ALI / ARDS / DAD (Diffused Alveolar Damage)

A

Same disease process just different names used in different departments

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4
Q

PATHOGENESIS OF ADA:
Name the 2 stages of ADA

A
  1. Early / exudative
    ○ Endothelial activation
    ○ Adhesion and extravasation of neutrophils
    ○ Accumulation of intra-alveolar fluid and formation of hyaline
    membranes
  2. Organising / proliferative
    -Type 2 pneumocyte hyperplasia
    -Increase of fibroblasts and myofibroblasts within the alveoli wall
    - Interstitial inflammation and fibrosis

● Chronic or fibrotic stage which resolves the injury

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4
Q

PATHOLOGIC FINDINGS OF DAD:
What are the expected findings of DAD macroscopically?

A

Heavy, firm, red, boggy lung

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4
Q

What are the characteristics of DAD survivors?

A

Survivors:
- Recover, some may have persistent impairment in cognitive and physical function
- Chronic lung disease : scarring, interstitial fibrosis, end stage/honeycomb lung

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4
Q

Restrictive Lung Diseases are classified according to the anatomical occassion that is affected. What 2 anatomical occassions are normally affected on RLD?

A
  1. Chest wall disorders
    These include:
    -Neuromuscular diseases
    incases of-
    ○ Poliomyelitis
    ○ Severe obesity
    ○ Pleural disease
    ○ Kyphoscoliosis
  2. Chronic diffuse ‘interstitial diseases’ of the lung parachyma
    These include:
    -Fibrosing diseases
    ○ Granulomatous disorders
    ○ Smoking-related interstitial diseases
    ○ Other:
    ■Langerhans cell histiocytosis
    ■Pulmonary alveolar proteinosis
    ■Lymphoid interstitial pneumonia
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5
Q

PATHOLOGIC FINDINGS OF DAD:
What are the expected findings of DAD microscopically?

A

Early stage:
- Congestion
- Interstitial and intra-alveolar oedema
- Fibrin deposition
- Waxy hyaline membranes
- Fibrin-rich oedema fluid
- Cytoplasmic and lipid remnants of necrotic epithelial cells

Organising stage:
- Proliferation of type II pneumocytes
- Granulation tissue in alveolar walls and spaces
- Fibrous scarring may occur, not always
* May have superimposed bronchopneumonia

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6
Q

What do the patients hospitalized for DAD normaly present with?

A

Patients usually hospitalised for ALI:
- Dyspnoea, tachypnoea, cyanosis, hypoxaemia, respiratory failure
- Radiology : diffuse bilateral infiltrates
- Ventilation required : V/Q mismatch (uneven distribution of injured lung, some unaerated and collapsed, other regions almost normal), respiratory acidosis

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6
Q

Name the conditions or disoders that fall under fibrosing diseases

A

● Usual interstitial pneumonia
● Non-specific interstitial pneumonia
● Cryptogenic organising pneumonia
● Connective tissue disease-associated

● Pneumoconiosis
○Silicosis
○Asbestosis
○Coal workers pneumoconiosis

● Drug reactions
● Radiation pneumonia

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7
Q

What is pneumoconiosis?

A

● Non-neoplastic lung reaction to mineral dusts, particulates, chemical fumes and vapours in the workplace
● It is an occupational lung disease
● Examples of mineral dusts:
○ Silica - gold miners, stone workers, sandblasters
○ Asbestos : asbestos mines, ship builders, insulation, electrical work
○ Coal

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8
Q

Discuss the pathogenesis of pneumoconiosis

A
  1. Amount of dust retained in lung and airways
    a. Dust concentration duration of exposure, effectiveness of clearing mechanisms
  2. Size, shape and buoyancy of the particles
    a. Most dangerous particles : 1 -5 μm in diameter
  3. Particle solubility and physiochemical properties
    a. Small particles of high solubility may cause rapid onset lung damage
    b. Larger particles may resist dissolution
  4. Possible additional effects of other irritants
    a. Tobacco smoke
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8
Q

What is silicosis?

A

Common lung disease caused by inhalation of silica (crystallin silicon dioxide)

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9
Q

What is the site mostly affected by silicosis?

A

Upper lobes of the lung field

9
Q

Name 2 forms of silica

A
  • Amorphous ((quartz,cristobalite,tridymite)
  • Crystallline (silica particles with the capacity to cause fibrosis)
10
Q

What is the macroscopic and microscopic finding of silicosis?

A

-macroscopic: Tiny white nodules (+black if coal
dust present) on lung surface
- microscopic: Silicotic nodule/islet = concentric layers of hyalinized collagen surrounded by dense capsule of more condensed collagen

10
Q

Discuss the timeline of silicosis presentation following exposure

A
  • Presents after decades of exposure, or
  • occasionally as acute (accelerated or rapid) silicosis with heavy exposure for a few months to years.
10
Q

What is a life threatening disease associated with silica?

A

Associated with increased susceptibility to TB (due to effect of silica on pulmonary macrophages)

-Inhaled silica particles are phagocytosed by macrophages
○Activation of inflammatory mediators (Il-1 and IL-18)

10
Q

Differs from other inorganic dusts as it has oncogenic properties

A

asbestosis

11
Q
  1. Tiny white nodules (+black if coal dust present) in upper zones of lungs
  2. May undergo central softening and
    cavitation (superimposed
    TB/ischemia)
  3. Evolves to progressive massive fibrosis (PMF), area of scarring >1cm
  4. Fibrotic lesions may occur in hilar lymph nodes and pleura
A

Pathology of silicosis

12
Q

What are the 2 forms of asbestos?

A

● Serpentine
○Curly and flexible
○More common type

● Amphibole
○Straight, stiff and brittle
○More pathogenic due to aerodynamic properties and
solubility

13
Q

Discuss the pathology of asbestos-related disease

A

● Diffuse pulmonary interstitial fibrosis with asbestos bodies
● Fibrosis
○ Begins in lower lobes / bases and sub-pleurally
○ Fibrosis distorts lung architecture, eventual honeycomb-lung
● Asbestos bodies
○ Golden-brown, fusiform/beaded rods with a translucent center
○ Consist of asbestos fibers coated with an iron-containing proteinaceous material

14
Q

Macroscopic finding of asbestosis

A

pleural plaque- pleural thickening arising in the parietal pleura

15
Q

Which lung zones are affected on silicosis and asbestosis?

A

silicosis- Apex of the lung (upper zones)
Asbestosis- base (lower)

16
Q

How severe is coal worker pneumoconiosis (CWP)?

A

● Inhalation of coal particles and other dust
● Drastic decreased incidence worldwide due to dust reduction measures
● Usually benign, 10 % cases develop PMF (progressive massive fibrosis)

17
Q

Discuss the pathology of CWP

A

● Anthracosis (also seen in urban dwellers and tobacco smokers)
○ Inhaled carbon pigment engulfed by macrophages
● Coal macule and nodule: are small, discrete black spots seen in the lungs of individuals with coal workers’ pneumoconiosis (CWP),
○The maculaes represen Carbon-laden macrophages and delicate network of collagen fibres
● Progressive massive fibrosis (PMF)
○Intensely blackened scar >1cm-10cm, dense collagen and pigment, central necrosis due to ischemia

18
Q

Severe, rare lung disease resulting in right heart failure (corpulmonale)

A

Pulmonary hypertension

● Characterised by high blood pressure in the pulmonary arteries (arteries which deliver blood from the heart to the lung), mean arterial pressure >25mmHg

18
Q

Clinical features of pulmonary hypertension

A

shortness of breath, syncope, fatigue, chest pain,
tachycardia

19
Q

Ratio of right
ventricular weight
To left ventricular
weight is called?
The normal ratio is
1:2.3 - 3.3

A

Fultons ratio

The normal ratio is
1:2.3 - 3.3

If the ratio of <1:2.3
then cor pulmonale is
present

19
Q

What are the macroscopical and microscopical findings in pulmonary hypertension?

A
  • Macro-Right ventricular hypertrophy
  • Micro- Vasculopathy:
    Medial hypertrophy of the pulmonary muscular and elastic arteries and intimal
    fibrosis
  • Pulmonary arterial atherosclerosis
  • Severe : plexiform lesion (tuft of capillary formations producing web across
    the lumen of the vessel and outside it)