Pathology of Restrictive Lung Diseases Flashcards

1
Q

What is the interstitial of the lung?

A

The connective tissue space around the airways and vessels and the space between the basement membranes of the alveolar walls - capillaries and pneumocytes pushed apart

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2
Q

What can the alveolar wall be thickened by?

A

Interstitial infiltrate

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3
Q

How is lung compliance affected?

A

Reduced (stiff lungs)

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4
Q

How is FEV1 and FVC affected?

A

Both reduced

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5
Q

How is the FV1/FVC ratio?

A

Normal ratio

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6
Q

What do obstructive lung diseases do to residual volume?

A

Increase

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7
Q

How does restrictive lung disease affect residual volume?

A

Reduces it

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8
Q

How does restrictive lung disease affect expiratory reserve volume?

A

Reduces it

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9
Q

How is gas transfer affected?

A

Reduced due to diffusion abnormality

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10
Q

Why is gas transfer reduced in restrictive lung diseases?

A

The distance between alveoli and capillaries is increased as there is increases tissue in the interstitium

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11
Q

What does a diffuse lung disease present as?

A

Abnormal CXR
Dyspnoea - exertion then rest
Type I respiratory failure
Heart failure

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12
Q

Why do sufferers of restrictive lung disease experience type 1 respiratory failure?

A

It is much easier for carbon dioxide to diffuse across the thickened alveolar walls than it is for oxygen

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13
Q

What is diffuse avleolar damage associated with?

A
Major trauma
Chemical injury / toxic inhalation
Circulatory shock
Drugs 
Infection
Auto(immune) disease
Radiation
idiopathic
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14
Q

What is the evolution of DADs?

A

Oedema -> Hyaline membranes ->interstitial inflammation -> interstitial fibrosis

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15
Q

What are the histological features of DADs?

A
Protein rich oedema
Fibrin
Hyaline membranes
Denuded basement membranes
Epithelial proliferation
Fibroblast proliferation
Scarring-interstitium and airspaces
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16
Q

What is the acute response to parenchymal (interstitial) lung injury?

A

Diffuse alveolar damage (DAD)

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17
Q

What is another response of parenchymal lung injury, which can also carry on from the acute response?

A

Chronic response which leads to fibrosis or end-stage honeycomb lung

18
Q

What are three conditions that arise from the chronic response?

A
Interstitial Pneumonitis (UIP)
Granulomatoud responses: sarcoidosis, hypersensitivity pneumoniitis
19
Q

What are sarcoidosis?

A

A multisystem granulomatous disorder of unknown aetiology

20
Q

Describe the histopathology of sarcoidosis

A

Epithelioid and giant cell granulomas

Necrosis/caseation unusual

21
Q

What are the different presentation of sarcoidosis?

A
  1. Young adult - acute arthralgia, erythema nodosum, bilateral hilar lymphadenopathy
  2. Incidental abnormal CXR - no symptoms
  3. SOB, cough and abnormal CXR
22
Q

If patient experiences symptoms of sarcoidosis (i.e. presentation 1) when should they resolve?

A

After 2 years

23
Q

What treatment is given for sarcoidosis?

A

Costicosteroids (for SOB, cough)

24
Q

How is sarcoidosis diagnosed?

A

Clinical findings
Imaging finding
Serum Ca ++ and ACE
Biospy

25
Q

What are the antigens for hypersensitivity pneumonitis?

A

Thermophilic actinomycetes
Bird / animal proteins
Fungi (aspergillus spp.)
Chemicals

26
Q

What is the acute presentation of hypersensitivity pneumonitis?

A

Fever, dry cough, myalgia
Chills after Ag exposure
Crackles, tachypnoea, wheeze
Precipitating antibody

27
Q

What is the chronic presentation of hypersensitivity pneumonitis?

A

Insidious
Malaise, SOB, cough
Low grade illness
Crackles and some wheeze

28
Q

What is the histopathology of hypersensitivity pneumonitis?

A
Immune complex mediated by combine Type II and Type IV hypersensitivity reaction 
Soft centriacinar epithelioid granuloma 
Interstitial pneumonitis
Foamy histiocytes 
Bronchiolitis obliterans
29
Q

What is bronchiolitis obliterans in hypersensitivity pneumonitis?

A

Obstruction of the smallest airways of the lungs (bronchioles) due to inflammation

30
Q

What part of the lung is common for hypersensitivity pneumonitis?

A

Upper zone

31
Q

Where might UIP be seen?

A
Connective tissue disorders 
Drug reaction 
Post infection 
Industrial exposure: asbestos 
Most cryptogenic or idiopathic
32
Q

What is the histopathology of UIP?

A

Patchy interstitial chronic inflammation
Type II pneumocyte hyperplasia
Smooth muscle and vascular proliferation

33
Q

What are clinical signs of UIP?

A
Dyspnoea 
Cough 
Basal crackles 
Cyanosis 
Clubbing
34
Q

What are the investigations for UIP?

A
CXR
PFT (shows restriction)
Gas transfer (reduced)
35
Q

What are other patterns than can cause fibrosis or honey combing of the lung?

A
Asbestos
Silicosis 
Smoking related fibrosis 
Cryptogenic organizing pneumonia (COP)
Bronchiolitis obliterans organizing pneumonia (BOOP)
36
Q

What are the levels for Type I and Type II respiratory failure?

A

Type I - PaO2 < 8kPa (PCO2 normal)

Type II - PaCO2 > 6.5 kPa (PaO2 low)

37
Q

What are 4 abnormal states associated with hypoxaemia?

A

Shunt
V/Q mismatch
Diffusion impairment
Alveolar hypoventilation

38
Q

How does alveolar hypoventilation lead to low PaO2?

A

Increase PACO2, and thus PaCO2

Increase in PACO2 decrease PAO2, which causes PaO2 to fall

39
Q

How is a fall in PaO2 due to hypoventilation corrected?

A

Raising FlO2 (fraction of inspired air which is oxygen)

40
Q

What is the normal V/Q ratio?

A

Breath 4min/l, CO is 5l/min so normal V/Q = 0.8

41
Q

How does diffusion impairment affect equilibrium across alveoli?

A

Takes longer for blood and alveoli air to equilibrate, particularly for O2 - usually 0.25s, but may take 0.75s in disease