COPD Flashcards
What is COPD?
COPD is characterised by airflow obstruction. The airflow obstruction is usually progressive, not fully reversible and does not change markedly over several months. This disease is predominantly caused by smoking.
What is COPD an umbrella term for?
Emphysema and Bronchitis
What is emphysema?
Pathological process in which there is destruction of the terminal bronchioles and distal airspaces
This leads to loss of the alveolar surface area and therefore impairment of gas exchange.
It often progresses to the development of larger redundant airspaces called bullae within the lung.
Also destruction of supporting tissues surrounding the small airways. This means they collapse during expiration when the pressure outside the airways rises.
This results in airflow obstruction particularly affecting the small airways.
Also destruction of elastic tissue - hyperinflation of the lungs as they are unable to resit the natural tendency of the rob cage to expand outwards.
What is chronic bronchitis?
Chronic mucus hyperexcretion that commonly occurs in smokers.
Mucus hyper secretion is caused by inflammation in the large airways leading to proliferation of mucus producing cells in the respiratory epithelium.
The result is a chronic productive cough and frequent respiratory infections. In COPD, this frequently persists even after smoking has stopped.
Chronic bronchitis results in airflow obstruction due to remodelling and narrowing of the airways.
What are some causes of COPD?
Smoking (90% of cases)
Alpha-1-antitrypsin deficiency
Occupational exposure - coal dust
Pollution
Do all smokers develop COPD?
Approximately 15% of smokers will develop COPD
What are the symptoms of COPD?
Cough and sputum production. Although many don’t present until breathless
Breathlessness is often progressive
Exacerbations are associated with increased breathlessness and cough and sputum production -may be infective.
What is the MRC Dyspnoea score?
This is a score used to characterise breathlessness in relation to activities.
- Not troubled by breathlessness except on strenuous exercise
- Short of breath when hurrying or walking up a slight hill
- Walks slower than contemporaries on level ground because of breathlessness, or has to stop for breath when walking at own pace.
- Stops for breath after walking about 100m or after a few minutes on level ground.
- Too breathless to leave the house, or breathless when dressing or undressing
What are the signs of breathlessness?
Sometimes no signs
“Purse lip” breathing - protective manoeuvre to increase pressure within airways causing a reducing / delay in closure of airways
Tachypnoea
Using accessory muscle
Hyperinflation - diaphragm and other respects muscles working harder to ventilate lungs.
Wheeze or quiet breath sounds
Cyanosis, CO2 retention, right heart failure, with oedema
How does the spirometer of a COPD patient present?
FEV1 <80% predicted and FEV1/FVC ratio <70%.
This is an obstructive patter.
This is because there is limitation to the flow of air during expiration and therefore volume of air expired in the first second.
Made worse by airway collapse on expiration.
How can spirometry be used in COPD?
Diagnosis and severity of airflow obstruction.
Staging is used to categorise severity.
Mild = FEV1 - 50-80% Moderate = FEV1 - 30-49% Severe = FEV1 - <30%
How do you diagnose COPD?
Combination of signs, symptoms and spirometry (FEC1/FVC <70%).
Following features are suggestive of COPD:
- Smoker / ex-smoker
- Older and symptoms later
- Chronic productive cough
- Persistent and progressive breathlessness.
What other investigations can be done if suspect COPD?
Chest X-ray - exclude other diagnosis
HRCT - macroscopic alveolar destruction in emphysema.
ABG - respiratory failure
Alpha-1-antitrypsin blood test (younger people)
How common is COPD?
Common - 1 million people have COPD and often present between ages of 50-60yrs old.
How do you treat stable COPD?
'COPD care bundle' Stop smoking Pulmonary rehabilitation Bronchodilators Antimuscarinics Steroids Mucolytics Diet -supplement and review Supportive - flu vaccine
Long term oxygen therapy and lung volume reduction can be done if appropriate.
What drug therapy’s are there for stable COPD patients?
B2 agonists - salbutamol Steroids -inhaled Antimuscarinics Mucolytics Methylxanthines
What are the adverse effects of B2 agonists?
Tachycardia (atrial B-2 receptors) Tremors (skeletal B-2 receptors) Anxiety Lapitations Hypokalaemia (skeletal muscle uptake K+)
Give examples of anticholinergics
Atropine
Ipratropium
Tiotropium
Synergistic with B-2 agonist
What are some side effects of anticholinergics?
Local: Dry mouth and cough Sore throat Pharyngitis URTI Bitter taste
Severe: Supra-ventricular tachycardia AF Urinary difficulty Urinary retention Constipation
How do methylxanthines work?
Bronchodilation
Increase respiratory drive
Anti-inflammatory effects
They work by inhibiting phosphodiesterases which break down cAMP so, the increasing levels of cAMP causes bronchodilation
What are side effects of high dose, long term steroids?
Thin skin Bruising Cataracts Adrenal insufficiency - key if long term and stop taking - risk of adrenal crisis Osteoporosis Diabetes Increased weight (fluid retention) Mental disturbance GI symptoms Proximal myopathy
What is carbocysteine?
A mucolytic
Reduce thinckness of sputum hoping with airway clearance
What is pulmonary rehabilitation?
Supervised exercise program - get them fit so they stay fit and use muscles.
Stop them avoiding exercise because of the breathlessness.
What is long term oxygen therapy and who is it used for?
Extended periods of hypoxia causes renal and cardiac damage - can be prevented by LTOT
Continuousness oxygen therapy for most of the day - at least 16 hours per day for survival benefit.
LTOT offered if pO2 constantly below 7.3kPa or below 8kPa with cor pulmonale
Must be non-smokers and not retina high CO2
Oxygen does not hep with breathlessness, treatment of hypoxia to prevent end organ damage
What surgical options are there for COPD patients?
Lung volume reduction - the reduction of hyperinflation
Lung transplant - if younger
How do you manage a patients with COPD exacerbations?
Controlled O2 therapy / Target saturation’s
Nebulisers - bronchodilators
Steroids - oral
Antibiotics of infective features - raised CPP /WCC
Consider IV aminophylline
Repeat ABG
What is non-invasive ventilation?
The provision of ventilators suppport through the patients upper airway using a mask or similar
What are the contraindications to NIV?
Untreated pneumothorax Impaired conscious level Upper airway secretions Facial injury Vomiting Agitated Life threatening hypoxia
