Pathology of Restrictive Lung Disease

Question 1

What is the interstitium of the lung

Answer 1

The connective tissue space around the airways and vessels and the space between the basement membranes of the alveolar walls

Question 2

What is in direct contact in normal alveolar walls

Answer 2

Most of the alveolar epithelial (pneumocyte) and interstitial capillary endothelial cell basement membranes

Question 3

What can enter the alveolar wall space in restrictive lung diseases

Answer 3

Inflammatory cells, fibroblasts and collagen

Question 4

What does the presence of inflammatory cells, fibroblasts and collagen in the alveolar wall space cause

Answer 4

Increased diffusion distance of air

Question 5

What do inflammatory cells, fibroblasts and collagen in the alveolar wall develop into and what does this cause

Answer 5

Fibrosis causing the lungs to become stiff due to an increase in the amount of elastic tissue and reduction in stretch ability due to the excess components present in the alveoli wall

Question 6

What are the 4 main features of restrictive lung diseases

Answer 6

Reduced lung compliance (stiff lungs)
Low FEV1 and FVC but FEV1/FVC ratio is normal
Reduced gas transfer (Tco or Kco) – diffusion abnormality
Ventilation/perfusion imbalance – when small airways are affected by pathology

Question 7

Why is there a reduction in FEV1 and FVC

Answer 7

Because there is a lung volume reduction

Question 8

Do restrictive lung diseases have air flow limitation

Answer 8

No

Question 9

How can gas transfer be measured

Answer 9

By the movement of CO that is breathed in in a single breath and can be measured in the blood to calculate the transfer of CO from air to the blood

Question 10

How much V/Q imbalance is seen in some restrictive lung diseases

Answer 10

Small amount

Question 11

How are diffuse lung diseases normally found

Answer 11

Abnormal CXR

Question 12

How will diffuse lung diseases present

Answer 12

Dyspnoea

Type 1 respiratory failure leading to heart failure

Question 13

Is the dyspnoea found in diffuse lung disease upon exertion or at rest

Answer 13

Upon exertion but as the disease progresses it will be present at rest also

Question 14

How many ribs will be seen on a chest X-Ray of interstitial lung disease

Answer 14

Less than 10 with more markings between the ribs

Question 15

Where is the site of inflammation in interstitial lung disease

Answer 15

Parenchymal

Question 16

What type of inflammation can parenchymal lung injury cause

Answer 16

Acute or Chronic

Question 17

How many pathways does chronic inflammation have. Name them

Answer 17

3
Usual interstitial pneumonitis (UIP)
Granulomatous responses
Other patterns

Question 18

What do all of the chronic inflammation pathways lead to

Answer 18

Fibrosis or End-stage Honeycomb Lung

Question 19

What can end stage pulmonary fibrosis lead to

Answer 19

Respiratory failure

Question 20

Which process is most likely to lead to end stage pulmonary fibrosis

Answer 20

UIP

Question 21

Which process is least likely to lead to end stage pulmonary fibrosis

Answer 21

Granulomatous response

Question 22

Give an example of acute inflammation due to parenchymal lung injury

Answer 22

Diffuse Alveolar Damage DAD

Question 23

What is DAD associated with

Answer 23

Major trauma
Chemical injury / toxic inhalation
Circulatory shock
Drugs 
Infection
Auto(immune) disease
Radiation
But it can be idiopathic

Question 24

What does DAD cause

Answer 24

A large leak in the capillaries of the alveolar walls

The damage to the capillaries is most likely mediated by neutrophil polymorphs

Question 25

What do some patients with DAD present with

Answer 25

Severe respiratory failure and admitted straight to ITU | Over 50%

Question 26

Where is fibrosis found in DAD

Answer 26

Interstitial space and alveoli walls

Question 27

What are the histological features of DADS

Answer 27

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

Question 28

Why is proliferation seen in DADS

Answer 28

To try and repair the damage caused

Question 29

What is the fluid and protein found in DADS transformed to

Answer 29

Fibrous tissue which forms a solid lung

Question 30

What can a granulomatous response cause

Answer 30

Sarcoidosis | Hypersensitivity pneumonitis

Question 31

What is sarcoidosis

Answer 31

A multisystem granulomatous disorder of unknown atiology

Question 32

What are the characteristic features of sarcoidosis in histopathology

Answer 32

Epithelioid and giant cell granulomas Necrosis/caseation very unusual Little lymphoid infiltrate Variable associated fibrosis

Question 33

Can sarcoidosis lead to fibrosis

Answer 33

Yes but unlikely to lead to end-stage fibrosis

Question 34

Who is commonly affected by sarcoidosis

Answer 34

Young adults | Females more than males

Question 35

What is the incidence of sarcoidosis in the UK

Answer 35

3-4/100,000

Question 36

What is the incidence of sarcoidosis in Afro-Americans the USA

Answer 36

20/100,000

Question 37

What will a young adult with sarcoidosis show

Answer 37

Acute arthralgia Erythema nodosum Bilateral hilar lymphadenopathy

Question 38

Can sarcoidosis be discovered when there are no symptoms

Answer 38

Yes in an incidental abnormal CXR | May resolve, persist or progress

Question 39

What else can patients with sarcoidosis present with

Answer 39

SOB Cough Abnormal CXR May resolve, persist or progress

Question 40

Do young patients presenting with acute arthralgia, erythema nodosum and bilateral hilar lymphadenopathy require treatment

Answer 40

No | It is a self-limiting condition which resolves within 2 years

Question 41

How is sarcoidosis treated with

Answer 41

Corticosteroids

Question 42

What 4 things can be used to diagnose sarcoidosis

Answer 42

Clinical findings Imaging findings Elevated serum Ca++ and ACE Biopsy

Question 43

What is hypersensitivity pneumonitis

Answer 43

A reaction to inhaled antigens (normally of organic origin)

Question 44

Name some type of antigens which can cause hypersensitivity pneumonitis

Answer 44

``` Thermophilic actinomycetes (e.g. Micropolyspora faeni, Thermoactinomyces vulgaris) Bird/Animal proteins - faeces, bloom Fungi - Aspergillus spp Chemicals Others ```

Question 45

What do you see in the acute presentation of hypersensitivity pneumonitis

Answer 45

Fever, dry cough, myalgia, Chills 4-9 hours after antigen exposure Crackles, tachyopnoea, wheeze Precipitating antibody

Question 46

What do you see in the chronic presentation of hypersensitivity pneumonitis

Answer 46

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

Question 47

What is one of the most important aspects when seeing a patient with suspected hypersensitivity pneumonitis

Answer 47

History

Question 48

Is acute or chronic hypersensitivity pneumonitis seen more often

Answer 48

Chronic

Question 49

What type of hypersensitivity reaction is hypersensitivity pneumonitis

Answer 49

Immune complex mediated | Type III and type IV hypersensitivity reaction

Question 50

What can hypersensitivity pneumonitis lead to

Answer 50

Soft centriacinar epithelioid granulomata Interstitial pneumonitis Foamy histiocytes Bronchiolitis obliterans

Question 51

Which part of the lung does hypersensitivity pneumonitis affect

Answer 51

Upper Zone