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
Give 1 example of a mucolytic drug used in COPD.
Carbocysteine
Apart from respiratory failure, what other complication can be caused by COPD?
List 2 features of this condition.
Cor pulmonale
FEATURES:
Right sided heart failure secondary to lung disease
Salt and water retention leading to peripheral oedema
How is end-stage COPD treated? (2)
Non-invasive ventilation (continuous positive airway pressure)
Long term oxygen therapy
What are the 3 criteria for long term, home oxygen therapy?
Non-smoker
pO2 <7.3
pO2 7.3-8.0 with any of the following:
- Secondary polycytaemia
- Nocturnal hypoxaemia
- Peripheral oedema
- Pulmonary hypertension
How do you measure pack years for smoking?
Pack years = (number of packs per day) x years of smoking
NOTE: one pack is 20 cigarettes
Summarise chronic COPD treatment. (10)
LIFESTYLE CHANGES:
- Smoking cessation
- Regular exercise
DRUG THERAPY:
- Inhaled beta 2 agonist
- Inhaled anti-muscarinic drugs (e.g. tiotropium, ipratropium bromide)
- Inhaled theophylline
- Inhaled corticosteroids
- Oxygen therapy
- Mucolytic drugs (e.g. carbocysteine)
- Nebulised therapy (e.g. bronchodilators, steroids)
RISK ASSESSMENT:
A-B: low risk of exacerbations
C-D: high risk of exacerbations
How would you treat end-stage COPD? (3)
Non-invasive ventilation (continuous positive airway pressure)
Pulmonary rehabilitation
Long term oxygen therapy
Which investigations would you do for an acute exacerbation of COPD? (6)
ABGs
CXR (to exclude infection, pneumothorax)
Bloods, e.g.
- FBC
- U&Es
- CRP
- Theophylline levels
ECG
Sputum cultures
Blood cultures (if pyrexial)
How would you treat an acute exacerbation of COPD?
- Nebulised bronchodilators, e.g.
a. Salbutamol
b. Ipratropium - Controlled oxygen therapy (start at 24-28%; aim for sats 88-92%)
- Steroids, including:
a. IV hydrocortisone
b. Oral prednisolone - Antibiotics (if evidence of infection)
- IV theophylline (if no response to nebulisers/steroids)
- Non-invasive ventilation (if no response to theophylline)
- Intubation and ventilation (if no response to NIV)
What is the empirical antibiotic therapy for non-severe infectious exacerbations of COPD?
For how long?
What route?
Oral amoxicillin, OR
Oral doxycycline, OR
Oral clarithromycin
Duration: 5 days
What is the empirical antibiotic for severe infectious exacerbations of COPD?
For how long?
What route?
IV amoxicillin, OR
IV clarithromycin
Duration: 7 days