Pathology of Obstructive Lung Diseases Flashcards
Name 3 types of obstructive airway diseases
Chronic Bronchitis
Emphysema
Asthma
What is Chronic Bronchitis and emphysema better known as
Chronic Obstructive Pulmonary Disease (COPD)
What is FEV1
The Forced Expiratory Volume of air that can exit the lung in the first second after taking a deep breath in
What is FVC
Forced vital capacity
The final total amount of air expired
How much of FEV1 makes up FVC
About 70-80%
What is the normal FEV1 in litres
3.5 - 4 L
What is the normal FVC in litres
5 L
What is the normal FEV1:FVC ratio
0.7-0.8
What is predicted FVC based on
Age, sex and height
How can the obstructed lung disease be demonstrated
Using PEFR (Peak Expiratory Flow Rate)
What is a normal PEFR in litres
400-600 litres/min
What is considered the normal range for PEFR
80-100% of best values
What is considered a moderate fall for PEFR
50-80% of best values
What is considered a marked fall for PEFR
Under 50% of best values
What is the main limitation caused by obstructive lung disease
Aiflow limitations
What happens to the PEFR, FEV1 and FVC values in obstructive lung diseases
PEFR and FEV1 is reduced
FVC may be reduced
FEV1 is less than 70% of FVC
What type of hypersensitivity does bronchial asthma have
Type 1 hypersensitivity of the airway
What occurs in bronchial asthma
Simultaneous contraction of smooth muscle and inflammation
What is the identifying factor of bronchial asthma
Its reversibility
Why is bronchial asthma considered a reversible airway obstruction
As it can be reversed spontaneously or with medical intervention
What can mimic bronchial asthma in adults
Chronic bronchitis
What are the causes of chronic bronchitis and emphysema
Smoking
Atmospheric Pollution
Occupation: dust
What is an extremely rare cause of emphysema
Alpha-1-antiprotease (antitrypsin) deficiency
Why is chronic bronchitis more common in the elderly
As these conditions are caused by the buildup of pollution and smoking which will cause these individuals to become more susceptible
Why is chronic bronchitis and emphysema more common in men
Due to higher patterns of smoking in men and their occupation
In what type of countries are chronic bronchitis and emphysema increasing
Developing countries
What is the clinical definition of chronic bronchitis
Cough productive of sputum most days in at least 3 consecutive months for 2 or more consecutive years (excludes TB, bronchiectasis etc)
When is chronic bronchitis considered chronic
When it becomes mucopurulent (acute infective exacerbation) or FEV1 falls below 0.7
What morphological changes occur in the large airways in chronic bronchitis
Mucous gland hyperplasia
Goblet cell hyperplasia
Minor component of inflammation and fibrosis
What morphological changes occur in the small airways in chronic bronchitis
Goblet cells appear
Inflammation and fibrosis in long standing disease
What is the pathological definition of emphysema
An increase beyond the normal in the size of airspaces distal to the terminal bronchiole arising either from dilatation or from destruction of their walls and without obvious fibrosis
What is emphysema
The loss of lung tissue due to the destruction of alveolar walls
Name the 4 different types of emphysema
Centriacinar
Panacinar
Periacinar
Scar (‘irregular’ and ‘Bullous emphysema’)
What is centriacinar emphysema associated with
Smoking
What does centriacinar emphysema begin with
Bronchiolar dilatation then causes alveolar tissue to be lost
What does panacinar emphysema cause and where is it mainly found
A massive loss of lung tissue and predominates in the lower zones of lungs
What is a bulla
Emphysematous space greater than 1cm
What is a bleb
The space just underneath the pleura
What does periacinar emphysema tend to affect
The acinar that are near the pleura by forming a bleb which can burst causing a pneumothorax
How do people with emphysema find it easier to breath
Find it easier to breath while retaining a small amount of air in their lungs
What is constantly present in low levels in alpha 1 antitrypsin deficiency
Anti-elastase
What is increased and decreased in smoking
Increased: Neutrophils Macrophages Elastases Decreased: Anti-elastases Repair mechanism elastin synthesis
How do the large airways contribute to airway obstruction in COPD
There is a small contribution by the glands and mucous
How do the small airways contribute to airway obstruction in COPD
Through: Smooth muscle tone Inflammation Fibrosis Partial collapse of airway walls on expiration
Which part of the small airways in COPD is able to respond to pharmacological intervention
Smooth muscle tone
Inflammation
What causes airflow limitation in emphysema
Loss of alveolar attachment
What does alveolar hypoventilation cause
Type 2 respiratory failure
