L5 COPD Flashcards
What is Cronic Obstructive Pulmonary Disease (COPD)?
Involves emphysema and chronic bronchitis and is characterised by reduced airflow in the lungs.
Generally affects middle aged and older people.
Smoking is major risk factor.
COPD is usually permanent and irreversible.
Compare the inflammatory mediators present in asthma and COPD, and their response to corticosteroids.
ASTHMA: CD4+ T lymphocytes, B lymphocytes, mast cells and eosinophils.
COPD: macrophages and neutrophils.
What are the symptoms of COPD?
Cough Mucus production Shortness of breath, particularly with exercise Wheezing upon inhalation Tightness in chest
Which factors should be avoided, and what can worsen COPD?
Smoking cessation decreases rate of decline in lung function by 50%
Smoking, dust, fumes and pollutants must be avoided
respiratory infection can worsen progress of disease
Define emphysema.
Alveolar enlargement caused by destruction of alveolar walls.
Abnormal accumulation of air in alveoli, due to reduced ability of the alveoli to recoil (loss of elasticity).
As ir continues to collect in the alveoli, they become enlarged, may break, or become damaged and form scar tissue.
What is usually the first symptom of emphysema?
Shortness of breath during exertion.
Describe the pathophysiology of emphysema.
Environmental insult such as tobacco smoke stimulates alveolar macrophages to produce chemokines to attract neutrophils.
Neutrophils and macrophages release proteinases that degrade elastin.
Alveoli degrade and coalesce to form enlarged airspaces typical of emphysema.
Also increase in mucous production and fibrosis.
What is a genetic disorder that may lead to development of emphysema?
What is the normal role of the enzyme, and how does cigarette smoke affect it?
alpha-1 trypsin deficiency.
Usually neutralises proteases. Cig smoke can activate and attract inflammatory cells into the lung, and so promotes the release of proteases such as elastase.
Cig smoke also inactivates endogenous protease inhibitors including alpha-1 anti-trypsin, further supporting protease activity and increasing risk of tissue damage.
What are the symptoms of emphysema?
Marked dyspnoea
later development of productive cough
rapid breathing (tachypnoea) with prolonged expiration
barrel chest
normal or elevated haematocrit
later development of ‘cor pulmonale’ (change in right ventricle due to respiratory disorder.
What treatments are available for emphysema?
Smoking cessation
prophylactic Abx
bronchodilators
cautious oxygen administration
What is the pathophysiology of chronic bronchitis?
Inflammation and swelling of the lining of the airways, resulting in airway narrowing and obstruction.
Production of mucous which can further obstruct the airways. Obstruction increases likelihood of bacterial lung infections.
How is a clinical diagnosis of chronic bronchitis made?
Chronic cough with production of sputum for 3 or more months during 2 consecutive years, that cannot be attributed to another cause.
What is the first symptom of chronic bronchitis?
Persistent, productive cough.
What causes the airway obstruction in chronic bronchitis? What are the precipitating causes of CB?
Inflammation and thickening of the mucous membrane lining airways, colliery impairment and accumulation of mucous and pus.
precipitating causes include cigarette smoke, air pollutants and infection.
What are the symptoms of chronic bronchitis?
Exercise intollerance late dyspnoea Wheezing productive cough Hypoxemia leacing to increased haematocrit and cyanosis early col pulmonale
Even though drugs do not modify decline in lung function in COPD, what benefits do they have?
Provide relief of symptoms
Improve exercise tollerance
Improve quality of life
Prevent or treat exacerbations and complications of COPD
List treatments available for chronic bronchitis.
Bronchodilators (both relievers and controllers)
Expectorants
Postural drainage
Possible steroids (late in disease)
Possible antibiotics for acute exacerbations.
List drugs for stable COPD
Short acting bronchodilators such as SA beta-2 agonists (salbutamol and terbutaline), and ipratropium (anticholinergic)
Long acting bronchodilators such as LABAs (salmeterol, eformoterol and indacaterol) and tiotropium.
Inhaled corticosteroids.
Theophylline.
What benefits do short-acting bronchodilators have in COPD treatment? What are their limitations?
Releive symptoms, inprove exercise tollerance and used for initial COPD management. Anticholinergics may be preferred, because many COPD patients have concomitant coronary artery disease.
Most patients with COPD have chronic breathlessness and so SA relievers are less beneficial than LA drugs in COPD.
What are the indications for use of indacarerol, its duration of action and common adverse effect?
Indicated for maintenance treatment of COPD only. has up to 24 hour duration of action, so only needs to be taken once daily.
Common adverse effect is a post inhalation cough.
What is tiotropium, its dosage form and counselling.
Long acting anticholinergic bronchodilator used only for the maintenance of COPD. available as DPI (spiriva).
Should not be used for immediate relief of symptoms.
Powder should not come into contact with eyes. Tell doctor if you have eye pain, blurred vision or visual halos.
Describe anticholinergic effects.
Anticholinergic inhalers alone are unlikely to cause anticholinergic effects, but the effects of many drugs together which have anticholinergic properties may summate.
Common effects include dry mouth, that irritation and dizziness. less frequent is blurred vision, and rare is urinary retention, constipation, closed angle glaucoma and palpitations.
Describe the use of inhaled corticosteroids for stable COPD treatment.
May be added to LA bronchodilators in patients with 2 or more exacerbations per year.
Possibility of increased pneumonia in patients on inhaled corticosteroids needs investigation.
Macrophages and neutrophils are less responsive to corticosteroids so drug is of limited benefit. They do however decrease the frequency and severity of acute exacerbations of COPD.
When is theophylline used for treatment of COPD?
Only used in patients who remain symptomatic despite optimal use of inhaled therapy.
