CSIM 1.70: Respiratory Disease 2

Question 1

What are the four COPD diseases?

Answer 1

• Emphysema
  
  • Chronic bronchitis
  • Asthma
  • Bronchiectasis

Question 2

Describe emphysema pathogenesis and the commonest patterns of its pathology.

Answer 2

The abnormal and permanent enlargement of airspaces distal to terminal bronchioles, coupled with the destruction of the alveolar walls.

Centriacinar emphysema
• nearer to the larger-calibre airways
• This is because neutrophils recruited during inflammation release elastase, which break down the elastin the the alveolar walls
• This is in response to smoking (similar to interstitial lung disease pathogenesis)
• DISTAL ALVEOLI ARE SPARED

Panacinar emphysema
• Not centred
• The liver ceases to produce enough alpha-1 antitrypsin (which usually inhibits elastase), therefore elastase in ALL lung tissues is dysregulated, and breaks down too much elastin
• This is why this pathology leads to more widespread emphysema - termed panacinar emphysema

The loss in functional surface area results in a loss of perfusion and therefore a response to lower perfusion. Therefore pulmonary BP will increase, causing heart failure

IMG 172

Question 3

What are the symptoms of emphysema?

Answer 3

‘Pink Puffers’
• Breathlessness
• Heart failure
• Pneumothorax

Question 4

What is irregular paraseptal emphysema

Answer 4

A more benign form of emphysema in which distal lung tissue adjacent to the pleura in the upper lobes undergoes fibrosis

Question 5

Describe chronic bronchitis? What are the clinical features of this?

Answer 5

• Persistent cough with sputum production
  
  • Three months within 2 years for diagnosis
  • Hypertrophy of mucus glands with hypersecretion

Clinical features: blue bloater
  •  Cyanotic
  •  Peripheral oedema 
  •  Cor pulmonale
  •  Wheezing 

NB: emphysema and chronic bronchitis are usually concurrent. Blue bloater vs pink puffer is not always useful, although one is usually more dominant over the other

Question 6

Define asthma. Describe it’s pathogenesis.

What 3 changes occur in asthma when chronic?

Answer 6

Chronic disorder with increased irritability of the bronchial tree and REVERSIBLE narrowing
• Allergen exposure causes a type 1 hypersensitivity reaction (mast cells release IgE and vasoactive cytokines)
• Oedema and mucus plugs obstruct the airways
• EOSINOPHILIC infiltrate

Chronic changes:
• Thickening and fibrosis of bronchial basement membrane
• Mucus gland atrophy
• Smooth muscle hypertrophy

Question 7

What is non-atopic asthma?

Answer 7

An asthma not caused by any identifiable allergen - ‘innate’ inflammatory role. Usually triggered by infections but primary cause is unknown, occurs in adults.

Question 8

What is bronchiectasis?

What does this lead to in terms of mucus?

Answer 8

Chronic infection of bronchi and bronchioles which leads to permanent dilatation due to scarring and distortion

This leads to pooling and poor clearance of mucus causing sepsis and amyloid production

Question 9

What are the two forms of bronchiectasis?

Answer 9

Diffuse form
• All tissues of the lung, implying a genetic cause
• E.g. CF, immune deficiencies

Localised form:
• Scarring due to an external factor
• E.g. due to infection, tumour, irradiation

Question 10

In which decades of life does lung cancer typically present?

What type of PRIMARY lung cancer is the most common and what are the types of it?

Answer 10

6th-7th

95% are bronchogenic carcinomas:
• Adenocarcinoma [glandular differentiation] (40%)
• Squamous cell carcinoma [squamous differentiation] (30%) - IMG 173
• Large cell undifferentiated [lack the architectural features of small cell carcinoma and glandular or squamous differentiation] (10%)
• Small cell carcinoma (15%) - IMG 174

Remaining 5% are bronchial carcinoid tumours (mostly treatable with surgery) NO SMOKING ASSOCIATION

Question 11

Where do adenocarcinomae tend to appear in the lungs? Where do they typically spread to?

Answer 11

Found at the periphery - Spreads to the nodes and pleura

Question 12

Where are squamous cell carcinoma usually found? Describe these.

Describe what hormonal effect these can have

Answer 12

Central tumour (near hilum)
• Strongest association with smoking
• Keratinisation occurs

May secrete parathyroid-hormone-like peptides, which cause:
• hypercalcaemia
• hypertrophic pulmonary osteopathy

Question 13

Where are small cell carcinoma usually found? Describe these

Answer 13

Centrally (near hilum)
• Most aggressive
• Poorly differentiated cells
• Neuroendocrine differentiation (ADH, ACTH)

Question 14

What are the most common sources of metastases to the lung?

Answer 14

• Breast
  
  • GI: Colon & Gastric

NB: lymphovascular spread