Pathology of lung disease

Question 1

Define asthma

Answer 1

Reversible airway obstruction due to crosslinking of receptor bound IgeE antibodies = mast cell degranulation of histamine = mucus plugging, mucosal oedema, mucus hypersecretion and bronchocontriction

Question 2

What is atopic asthma?

Answer 2

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

Question 3

What causes the asthmatic response?

Answer 3

Inflam reaction caused by mast cells in the bronchi.
On surface of mast cells = IgE antibodies = formed by body to some sort of allergen
Asthmatic inhales the allergen = binds to specific IgE antibodies on the mast cell surface and cross links the antobodies
Crosslinking antibodies = mast cells degranulate = releases inflam mediators from the mast cell to surrounding cells in the bronchus = acute inflam rxn

Question 4

How to treat atopic asthma?

Answer 4

Avoidance of antigen
Reduction in mast cells steroids
Stabilisation of mast cell membranes
Reversal of effects of chemical mediators salbutomol

Question 5

What is chronic obstructive airways disease?

Answer 5

Emphysema and chronic bronchitis

Question 6

Define chronic bronchitis

Answer 6

Cough and sputum for 3 months in 2 consecutive years

Question 7

Chronic bronchitis aetiology?

Answer 7

Cigarette smoking, air pollution

Question 8

Who is likely to have chronic bronchitis?

Answer 8

Middle aged men

Heavy cigarette smokers

Question 9

Pathology of chronic bronchitis?

Answer 9

Mucus hyper secretion
Chronic inflam
Squamous metaplasia
Dysplasia

Question 10

Microbiology of chronic bronchitis?

Answer 10

Bacteria 
- Haemophilus influenzae
- Streptococcus pneumoniae
 Viruses
- Rep syncytial virus
- Adenovirus

Question 11

Define emphysema

Answer 11

Enlargement of airspaces distal to the terminal bronchioles with destruction of elastin in walls

Question 12

Lung cancer prevalence?

Answer 12

52400 deaths/yr male

12600 deaths/yr female

Question 13

Causes of lung cancer?

Answer 13

Cigarette smoking
Asbestos exposure
Radon exposure
Nickel, chromate

Question 14

What happens to the lung’s epithelium when metaplasia occurs?

Answer 14

Lung goes from ciliated columnar, squamous, dysplastic, invasive cancer

Question 15

How to classify lung cancer?

Answer 15

Small cell

Non-small cell = adeno or squamous

Question 16

Prognosis of lung cancer?

Answer 16

15-20% of lung cancers are resectable
Rest are unresectable due to locally advanced tumours or metastasis
4-9% overall 5% survival rate = poor response to systemic chemo

Question 17

Economics of lung cancer? .

Answer 17

Probable positive economic balance

• Tax from cigarette purchases
• Develop the disease before or around retirement age
• Quick death
• Cheap treatment

Question 18

Economics of cigarette smoking?

Answer 18

Bad economically due to chronic obstructive airway disease, ischaemic heart disease

Question 19

What causes coalworker’s pneumoconisis?

Answer 19

Inhaling coal dust

Question 20

What causes silicosis?

Answer 20

Inhaling silicates (inorganic minerals abundant in stone and sand) = toxic to macrophages = cause inflam and fibrosis

Question 21

Asbestos-related diseases?

Answer 21

Pleural plaques
Pleural fibrosis
Mesothelioma
Asbestosis
Lung carcinoma

Question 22

What is mesothelioma?

Answer 22

Malignant tumour of pleural surface after asbestos exposure especially crocidolite
Long latent period

Question 23

How are lung cancer and asbestos linked?

Answer 23

Increased in subjects with asbestos exposure

Multiplicative effect with cigarette smoking