Obstructive airway diseases Flashcards
What are the three main obstructive airway diseases?
Chronic bronchitis
Emphysema
Asthma
Whats is chronic bronchitis and emphysema better know as?
COPD (chronic obstructive pulmonary disease)
What is PEFR ?
Peak expiratory flow rate
What are the characeristics of an obstructive lung disease?
- Airflow limitation
- Peak expiratory flow rateis reduced
- FEV1 reduced
- FVC may be reduced
- FEV1 is less than 70% of FVC
Describe bronchial asthma?
Type 1 hypersensitivity in the airways.
Degranulation of mast cells causing smooth muscle contraction and inflammation.
CONSIDERED REVERSIBLE
Name the aetiology of chronic bronchitis and emphysema:
- Smoking
- Atmospheric Pollution
- Occupation eg dust
Higher prevalence in men
Define chronic bronchitis clinically
Cough productive of sputum most days in at least 3 consectutive months for 2 or more consecutive years.
What is “complicated” Bronchitis?
If mucous is yellow or green - infection present. or FEV1 falls
What are the morphological changes in chronic broncitis in the large airways?
- Mucous gland hyperplasia
- Goblet cell hyperplasia
- Inflammation and fibrosis is a minor component.
What are the morphological changes in chronic broncitis in the small airways?
- Goblet cells appear
- Inflammation and fibrosis if disease is long standing.
What is the pathological definition of emphysema?
Increase beyond the normal size of airspaces distal to the terminal bronchiole arising either from dilation or from destruction of there walls without any obvious fibrosis.
What is the acinus?
After terminal bronchiole no longer completely lined in respiratory epithelium. (1-2cm in diameter)
What are the forms of emphysema?
- Centriacinar
- Panacinar
- Scar “irregular”
Describe centiacinar emphsema
Patchy diffusion in central acinus. Tends to happen in upper lobes
Describe panacinar emphysema?
Through out acinar.
Most in lower lobes
What is a bulla?
A bulla is an emphysematous space greater than 1 cm.
How many ribs should you be able to see in a normal chest x ray?
Normally 9-10
Describe the unlikely cause of emphysema
Alpha-1-antitrypsin deficiency
What does alpha-1-antitrypisin stop?
Healthy lung tissues being digested.
What does smoking cause?
- Increase in neutophils, macrophages
- Increase elastease/ Proteases
- Decreases Anti-elastase
- Decrease repair mechanisms
What aprts of emphysema respond to pharmacological intervention?
- Smooth muscle tone
- Inflammation
What is MOST important in emhysema?
Loss of alveolar attachments( like guy ropes for tent)
What do alveolar attachments do?
Pull small alveolar airways open.
Stop airways shutting too soon.
