Respiratory: Pathology - Pathology of obstructive airways disease Flashcards
What are the two types of distinctive lung diseases?
Obstructive lung disease
Restrictive lung disease
How can the airways be narrowed/obstructed?
- Muscle spasm
- Mucosal Oedema
- Airway collapse
- Localised obstruction due to tumour/foreign body
What are the two main respiratory obstructive diseases?
- Asthma
- COPD
What is chronic bronchitis?
A cough productive of sputum on most days for 3 months of at least 2 successive years
What does chronic irritation of the airways leads to?
leads to a defensive increase in mucous production with an increase in the numbers of epithelial cells; in particular, goblet cells
What are the symptoms of chronic obstructive disease?
- Chronic Irritation
- Non-reversible obstruction
- May be a reversible asthmatic component
- Small airways
- Goblet cell metaplasia
- Macrophage accumulation
- Fibrosis around bronchioles
What is emphysema?
Increase beyond the normal size of the airspaces distal to the terminal bronchiole (the gas-exchanging compartment of the lung)
What are the pattern types of emphysema?
o Centriacinar (centrilobular) – around bronchioles o Panacinar – around lobes, lung appears generally ‘ragged’ o Others (e.g. localised around scars in the lung)
How can emphysema be diagnosed?
- reduced breath sounds
- Radiology CT
What is the dilation in emphysema related too?
o Loss of alveolar walls - tissue destruction.
o Holes appear in lung tissue
o Loss of elastic recoil and support of small airways leading to tendency to collapse with obstruction
o Loss of support on bronchiolar walls
What are the chronic effects of COPD?
- PaO2 decrease leads to
Dyspnoea (shortness of breath) and increased respiratory rate
Pulmonary vasoconstriction (and pulmonary hypertension
What is the epidemiology of COPD?
- Smoking
- Atmospheric pollution
- Genetic factor
What does a high rate of emphysema suggest?
Alpha-1-antitrypsin deficiency
What is the pathology of emphsema?
- Proteases breaks down the protein walls
- Elastases
- Alpha-1-antitrypsin acts as an anti-elastase
What does Alpha-1-antitrypsin act as?
An anti-elastase
What actions does Tobacco smoke on the body?
- Increases number of neutrophils and macrophages in lung
- Slows transit of these cells
- Promotes neutrophil degranulation
- Inhibits alpha-1 antitrypsin
What is Bronchial asthma?
A chronic inflammatory disorder characterised by hyperreactive airways leading to episodic reversible bronchoconstriction
What is the pathology of bronchial asthma?
Narrowed oedematous airways
Mucus plugs
Inflammatory cells (lymphocytes, plasma cells, eosinophils)
Epithelial cell damage
What is asthma?
Type 1 hypersensitivity - allergen binds to IgE on surface of mast cells
Degranulation (histamine)
o muscle spasm
o inflammatory cell influx (eosinophils)
o inflammation/oedema
Inflammatory infiltrate tends to chronicity
