Pathology of lung disease

Question 1

Asthma definition

Answer 1

> irritability of the bronchial tree
-temporary reversible narrowing of airways due to inflammatory process occurring within those airways
Paroxysmal airway narrowing
Reversible
-spontaneous
-after treatment

Question 2

Atopic asthma

Answer 2

Triggered by environmental agents e.g. dust
Family history of asthma, hay fever etc.
Type I hypersensitivity reaction

Question 3

Atopy

Answer 3

Refers to genetic tendency to develop allergic diseases
-such as allergic rhinitis, asthma and atopic dermatitis (eczema)
Typically associated with heightened immune responses to common allergens, especially inhaled allergens and food allergens

Question 4

Inflammatory reaction (DIAGRAMS)

Answer 4

Caused by mast cells in bronchi
-on surface of these are IgE antibodies formed to some sort of allergen, usually some component of house dust
Upon inhaling allergen, it binds to specific IgE on surface of mast cell and cross links those antibodies
Cross-linking triggers mast cell to de-granulate
-releases large number of inflammatory mediators from mast cell into surrounding cells in bronchus causing acute inflammatory reaction

Question 5

Treating atopic asthma

Answer 5

Avoidance of the allergen
-e.g. cat/ dog allergy
-not possible for many e.g. pollen
Get rid of inflammatory mast cells from lungs
-inhaled steroid drugs e.g. beclomethasone
Prevent mast cells from granulating when antigen binds to specific IgE antibodies
-disodium cromoglycate
Reverse effects of chemical mediators released when mast cells degranulate
-salbutamol (beta-adrenergic stimulant)

Question 6

Chronic obstructive airways disease

Answer 6

Emphysema

Chronic bronchitis

Question 7

Chronic bronchitis definition

Answer 7

Cough and sputum for 3 months in 2 consecutive years

Question 8

Chronic bronchitis aetiology

Answer 8

Mainly cigarette smoking
Air pollution (Clean Air Act 1956)

Question 9

Chronic bronchitis - clinical features

Answer 9

Middle-aged men

Heavy cigarette smokers

Question 10

Chronic bronchitis - pathology

Answer 10

Mucous hypersecretion
Chronic inflammation
Squamous metaplasia
Dysplasia (but a feature of the causative agent)

Question 11

Chronic bronchitis - microbiology (infections/ acute exacerbations on top of chronic bronchitis)

Answer 11

Bacteria
-haemophilia influenzae
-streptococcus pneumoniae
Viruses
-respiratory syncytial virus
-adenovirus

Question 12

Definition of emphysema

Answer 12

Anatomical
Enlargement of airspaces distal to the terminal bronchioles with destruction of elastin in walls
-destruction of walls of alveoli can lead to coalescence of spaces to make larger air spaces
< SA for gas exchange
shows darker on radiograph

Question 13

Lung cancer epidemiology - deaths per year

Answer 13

Males in UK - 52400 deaths/ year
Females in UK - 12600 deaths/ year
-higher incidence in areas with higher social deprivation (smoking, diet?)

Question 14

Causes of lung cancer

Answer 14

Cigarette smoking 85-90% all cases
Asbestos exposure
Radon exposure (e.g. granite areas in Dark Peaks)
Nickel, chromate etc.

Question 15

Progression of cells in lung cancer

Answer 15

Ciliated columnar –metaplasia–> squamous –> dysplastic –> invasive cancer

Question 16

Types of lung cancer

Answer 16

Small cell
Non-small cell
-adeno
-squamous

Question 17

Prognosis of lung cancer

Answer 17

Only 15-20% of lung cancer are resectable at time of presentation
All the rest are unresectable due either to locally advanced tumours (e.g. gross involvement of subcarinal lymph nodes) or metastasis

Question 18

Prognosis of lung cancer

Answer 18

4. 9% overall 5 year survival rate

- this reflects the low percentage of resectable tumours and poor response to systemic chemotherapuy

Question 19

In pure economic terms does lung carcinoma have a positive or negative economic balance in Britain?

Answer 19

Probable +ve economic balance

• tax from cigarette purchases for 40 years
• develop disease just before or around retirement age
• treatment relatively cheap

Question 20

Economics of cigarette smoking

Answer 20

However even in economic terms alone cigarette smoking has an overall debit due to

• COPD
• ischaemic heart disease

Question 21

Industrial lung disease

Answer 21

Coalworker’s pneumoconiosis

-problem is the silica, not usually the coal dust

Question 22

Silicosis

Answer 22

Silicates = inorganic minerals abundant in stone and sand
Silicates are toxic to macrophages
Nodules and fibrosis

Question 23

Asbestos-related diseases

Answer 23

Pleural plaques
Pleural fibrosis
Mesothelioma
Asbestosis
Lung carcinoma
-body's reaction to asbestos contains iron

Question 24

Mesothelioma

Answer 24

Almost always associated with asbestos exposure especially crocidolite (Cape blue asbestos)
Malignant tumour of pleura
Long latent period
Incidence will continue to rise into 21st C

Question 25

Lung carcinoma and asbestos

Answer 25

> in subjects with asbestos exposure

Mutiplicative effect with cigarette smoking

Question 26

Pink puffers (look up)

Answer 26

Breathe fast

Okay oxygens

Question 27

Blue bloaters (look up)

Answer 27

Don’t breathe as fast
Look blue
Not enough oxygen going round

Question 28

Vaping

Answer 28

A bit safer, less carcinogens
-not burning things as much
Lung cancer risks considerably lower
May not lower risk of ischaemic heart disease