Lecture 6: The pathology of COPD Flashcards
(46 cards)
What is Chronic Obstructive Pulmonary Disease (COPD)?
A chronic slowly progressive disorder characterized by airflow obstruction
How is COPD diagnosed?
Reduced FEV1 and FEV1/VC ratio
What is the pathophysiology of COPD?
Implicates varying degrees of airway remodelling, inflammation, and tissue destruction.
How does COPD affect large airways (trachea, bronchi) ?
Glandular hypertrophy, reduced number of cilia so increased cough with or without sputum.
How does COPD affect small airways (bronchioles)?
Goblet cell metaplasia; smooth muscle hypertrophy; fibrosis and scar tissue this increases mucus production, increased expiratory flow resistance.
How does COPD affect alveoli?
Loss of alveolar fine structure - Loss of lung recoil – this is important to push air out of the lungs, reduced gas exchange because of reduced surface area
What are the structural changes of COPD?
- Remodelling of the upper airways
- Dysanapsis: disproportionate scaling of airway dimensions to lung volume or a mismatch of airway tree caliber to lung size.
- Inflammation and mucus hypersecretion
- Ventilation heterogeneity
- Loss of alveolar attatchment
- Alveoli with emphysema
What are the clinical symptoms of COPD?
- Symptoms include cough, sputum, dyspnea (shortness of breath), and wheeze.
- Patients who have chronic cough and sputum production with a history of exposure to risk factors should be tested for airflow limitation, even if they do not have dyspnea.
What are the diagnostic features of COPD?
- History of heavy smoking for many years.
- Cough and sputum production for many years.
- Cough often present only on waking at first; later cough occurs throughout the day.
- Sputum usually mucoid – becomes purulent with exacerbation of disease, but not excessive.
- Cough and sputum often worse in winter due to infection.
- Insidious onset of breathlessness on exertion with wheezing or tightness of chest
What are the diagnostic features of COPD?
- History of heavy smoking for many years.
- Cough and sputum production for many years.
- Cough often present only on waking at first; later cough occurs throughout the day.
- Sputum usually mucoid – becomes purulent with exacerbation of disease, but not excessive.
- Cough and sputum often worse in winter due to infection.
- Insidious onset of breathlessness on exertion with wheezing or tightness of chest
What are the two clinical phenotypes of COPD?
- Emphysema
- Chronic bronchitis
What is the clinical diagnosis of chronic bronchitis?
Daily productive cough for three months or more, in at least two consecutive years
What are the signs of chronic bronchitis?
- overweight and cyanotic
- Elevated hemoglobin
- Peripheral edema
- Rhonchi and wheezing
What is the pathologic diagnosis of emphysema?
Permanent enlargement and destruction of airspaces distal to the terminal bronchiole
What are the sings of emphysema?
- Older and thin
- severe dyspnea
- Quiet chest
- Xray, hyperinflation with flattened diaphragsm
What are the three types of chronic bronchitis?
- Simple mucoid bronchitis
- Mucopurulent (pus) bronchitis
- Chronic obstructive bronchitis
What are the clinical manifestations of chronic bronchitis?
- Excessive mucus production
- Leading to Bronchospasm, dyspnea and wheezing
- Hypoxia and hypercapnia (Blue in color)-elevated CO2
- Productive cough
- Increase body weight
What are the complications of chronic bronchitis?
Cor-pulmonale
What is cor-pulmonale
Also known as right sided heart failure, is an enlargement of the right ventricle due to high blood pressure in the lungs usually caused by chronic lung disease
What is the clinical definition of chronic bronchitis?
Clinically defined as persistent productive cough for at least three consecutive months in at least two consecutive years.
What is emphysema?
An abnormal permanent enlargement of air spaces distal to the terminal bronchioles, accompanied by destruction of their walls.
What does emphysema cause?
- loss of intricate alveolar architecture
- progressive simplification of small and highly effective gas-exchanging units into large, inefficient cyst-like spaces.
- loss of alveolar gas-exchanging units and the capillary bed so blood oxygen levels eventually fall and pressures within the pulmonary circulation rise
What is the effect of emphysema?
- Alveolar enlargement leads to progressively larger lungs that are fixed within an anatomically constrained chest cavity, limiting ventilation.
- Severe difficulty breathing
- Chronic respiratory failure, evidenced by low blood oxygen levels (hypoxemia), elevated levels of carbon dioxide (hypercapnia, hypercarbia, chronic respiratory acidosis)
- Eventually death
Describe the airways of obstructive chronic bronchitis
- Thick, sticky mucous blocks up the airways rather than clears
- Inflammation and swelling further narrows airways
