COPD (Chronic Obstructive Pulmonary Disease) Flashcards
Define COPD.
A chronic disease of progressive airway obstruction, which is irreversible and does not change markedly over several months
List 3 causes of COPD.
Smoking
Environmental pollution
Alpha 1 anti-trypsin deficiency
How does smoking cause COPD?
i.e.
Describe the effect of cigarette smoking on the lungs. (6)
- Reduced cilia motility/destruction of cilia
a. Causes reduced mucous clearance
b. Leads to increased frequency of infection and damaged lungs - Airway inflammation
- Mucous gland and Goblet cell hypertrophy
a. Causes increased mucous production
b. Leads to increased frequency of infection and clear sputum production - Increased protease activity and decreased production of anti-proteases
- Oxidative stress caused by inflammatory cells
- Squamous metaplasia
a. Causes increased risk of lung cancer
Briefly list the 6 effects of smoking on the lungs.
- Reduced cilia motility/cilia destruction
- Airway inflammation
- Mucous gland/Goblet cell hypertrophy
- Increased protease activity and decreased production of anti-proteases
- Oxidative stress
- Squamous metaplasia
Which mutation is found in an alpha 1 anti-trypsin deficiency?
Normal alleles: M
Alleles causing disease: SS and ZZ
How does an alpha 1 anti-trypsin deficiency cause COPD? (2)
- Normally, alpha 1 anti-trypsin is a serine proteinase inhibitor which inhibits destructive enzymes in the lung
- Deficiency of anti-trypsin is unable to counter-balance proteinases in the lung
a. Therefore lung destruction occurs
What are the 2 main aspects of COPD pathophysiology?
Define them.
Chronic bronchitis:
“Production of sputum on most days for at least 3 months, over at least 2 years”
Emphysema:
“Abnormal, permanent enlargement of the airspaces distal to the terminal bronchioles”
Describe the pathophysiology of chronic bronchitis. (5)
- Infiltration of bronchiole wall with:
a. Neutrophil
b. T lymphocytes
c. Macrophages - Release of inflammatory mediators from inflammatory cells
- Loss of interstitial support
a. This causes increased risk of airway collapse - Increased mucous production, caused by:
a. Increased numbers of epithelial goblet cells
b. Mucous gland hyperplasia - Squamous metaplasia
List 8 inflammatory mediators which are involved in chronic bronchitis.
HINT: there are 4 categories.
Chemokines, e.g.
- TNF
- IL-8
From neutrophils, e.g.
- Neutrophil elastase
- Proteinase 3
- Cathepsin G
From macrophages, e.g.
- Elastase
- MMPs
Reactive oxygen species
What are the 2 types of chronic bronchitis?
Bronchitis
-Affects larger airways (4+mm diameter)
Bronchiolitis
-Affects smaller airways (2-3mm)
What are the main features of bronchitis? (1)
What are the main features of bronchiolitis? (2)
BRONCHITIS:
Chronic inflammation leads to scarring and thickening of the airways
BRONCHIOLITIS:
- Narrowing of bronchioles due to mucous plugs
- Further narrowing due to inflammation and fibrosis
What are the 3 types of emphysema?
Centri-acinar
Pan-acinar
Paraseptal
Where are the 3 types of emphysema found?
Centri-acinar: around respiratory bronchioles (most often in upper lobes)
Pan-acinar: throughout whole acinus
Paraseptal: along the edges of the septum between acini
What are the features of pan-acinar emphysema? (2)
What are the features of paraseptal emphysema? (2)
Pan-acinar emphysema:
- Uniformly enlarged from the terminal bronchiole
- May form large bullae
Paraseptal emphysema:
- May form bullae
- Appears as lines around the septa
Describe the pathophysiology of emphysema. (2)
- Loss of surface area for gas exchange
- Loss of elastic recoil in bronchioles
a. This causes airway collapse on expiration
Describe the pathophysiology of COPD. (5)
- Airway inflammation
- Loss of elasticity of the alveoli and small bronchioles (caused by: emphysema)
a. This causes loss of alveolar attachments
b. This causes airway collapse on expiration - Small airway collapse on expiration
a. This causes air trapping and hyperinflation
b. This causes increased work of breathing
c. This causes breathlessness - Goblet cell metaplasia
a. This causes increased mucous production
b. This causes mucous plugging of small airways - Smooth muscle hypertrophy and peri-bronchial fibrosis
a. This causes thickening of the bronchiole wall
How would you diagnose COPD? (4)
- Smokers or ex-smokers
- Above 35 yo
- Clinical history of:
- Breathlessness on exertion
- Chronic cough
- Regular sputum production
- Frequent winter “bronchitis”
- Wheeze - Spirometry:
- Obstructive pattern, i.e. FEV1/FVC <70%
Describe how to classify COPD severity. (4)
Stage 1: mild
-Predicted FEV1: 80+%
Stage 2: moderate
-Predicted FEV1: 50-80%
Stage 3: severe
-Predicted FEV1: 30-50%
Stage 4: very severe
-Predicted FEV 1: <30%
OR
-Predicted FEV 1: <50% WITH respiratory failure
What investigations can be done for COPD? (3)
What is seen on each?
Chest x-ray:
- Hyperinflation
- Reduced lung markings
Flow-volume loop:
-Church and steeple appearance
Volume-time plot:
- Slow-rising curve
- Reduced FEV1
What are the 2 types of respiratory failure which might be seen in COPD?
Type 1 (pink puffers)
Features:
-Low pO2 and low/normal pCO2
-High respiratory drive
Type 2 (blue bloaters)
Features:
-Low pO2 and high pCO2
-Low respiratory drive THEREFORE DO NOT GIVE HIGH FLOW OXYGEN
Describe the symptoms of type 1 respiratory failure. (6)
Type 1:
- Low pO2
- Low/normal pCO2
Desaturation on exercise Pursed lip breathing Use of accessory muscles while breathing In-drawing of intercostal muscles while breathing Wheeze Tachypnoea (RR 20+)
Describe the symptoms of type 2 respiratory failure. (8)
Type 2:
- Low pO2
- High pCO2
Cyanosis Warm peripheries Bounding pulse Flapping tremor Confusion/drowsiness Right heart failure Peripheral oedema Raised JVP
List the 7 types of drugs that can be given for COPD.
Inhaled beta 2 agonists
Inhaled anti-muscarinic drugs
Inhaled theophylline
Inhaled corticosteroids
Oxygen therapy
Mucolytic drugs
Nebulised therapy (bronchodilators/steroids)
Give 2 examples of inhaled corticosteroids used in COPD.
Budesonide
Fluticasone
