COPD Flashcards
How is COPD defined?
A disease state characterised by airflow limitation that is not fully reversible. The airflow limitation is usually both progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases
What causes COPD?
COPD is caused by long-term exposure to toxic particles and gases
In developed countries, cigarette smoking accounts for over 90% of cases
What is the most consistent pathological finding in COPD?
The most consistent pathological finding in COPD is increased numbers of mucus-secreting goblet cells in the bronchial mucosa, especially in the larger bronchi
In more severe cases, the bronchi become overtly inflamed and pus is seen in the lumen
What part of the airways is mainly affected in COPD?
The small airways are particularly affected early in the disease, initially without the development of any significant breathlessness.
This initial inflammation of the small airways is reversible and accounts for the improvement in airway function if smoking is stopped early.
In later stages the inflammation continues, even if smoking is stopped
What microscopic changes can be seen in COPD?
Infiltration of the walls of the bronchi and bronchioles with acute and chronic inflammatory cells → lymphoid follicles may develop in severe cases
Further progression of the airways disease leads to progressive squamous cell metaplasia, and fibrosis of the bronchial walls
What is emphysema?
Emphysema is defined as abnormal, permanent enlargement of air spaces distal to the terminal bronchiole, accompanied by destruction of their walls and without obvious fibrosis. Emphysema leads to expiratory airflow limitation and air trapping
What does the loss of lung elastic recoil result in in COPD?
The loss of lung elastic recoil results in an increase in total lung capacity. Premature closure of airways limits expiratory flow while the loss of alveoli decreases capacity for gas transfer.
What loss ini FEV1 can be seen in COPD patients, compared to normal individuals?
There is a loss of 50mL per year in FEV1 in patients with COPD compared to 20mL per year in healthy people
What mechanisms (3) have been suggested for the limitation of airflow in the small airways in COPD?
- Loss of elasticity and alveolar attachments of airways due to emphysema. This reduces the elastic recoil and the airways collapse during expiration.
- Inflammation and scarring cause the small airways to narrow.
- Mucus secretion, which blocks the airways.
What three factors contribute to the pathogenesis of COPD?
- Cigarette smoking
- Infections
- alpha-antitrypsin deficiency
What do bronchoalveolar biopsies in COPD patients reveal histologically?
Bronchoalveolar lavage and biopsies of the airways of smokers show increased numbers of neutrophil granulocytes. These granulocytes can release elastases and proteases, which may help to produce emphysem
How does smoking contribute to the development of COPD?
α1-Antitrypsin is a major serum antiprotease which can be inactivated by cigarette smoke
It has been suggested that an imbalance between protease and antiprotease activity causes the damage
Mucous gland hypertrophy in the larger airways is thought to be a direct response to persistent irritation resulting from the inhalation of cigarette smoke. The smoke has an adverse effect on surfactant, favouring overdistension of the lungs.
What are the characteristics symptoms of COPD?
- Productive cough with white or clear sputum
- Wheeze
- Breathlessness
What factors worsen the symptoms in COPD?
Symptoms can be worsened by cold, foggy weather and atmospheric pollution
With advanced disease, breathlessness is severe even after mild exercise such as getting dressed. Apart from the pulmonary features, there are systemic effects including hypertension, osteoporosis, depression, weight loss and reduced muscle mass with general weakness.
What are the signs of COPD?
In mild COPD, there may. be no signs or just a quiet wheeze throughout the chest.
In severe disease there are more signs:
- Tachypnoeic
- Prolonged expiration
- Use of accessory muscles during inspiration
- Pursing of the lips on expiration
- Poor chest expansion and lungs are hyper-inflated, leading to hyper-resonance
- Loss of normal cardiac and liver dullness
What happens to the respiratory quality in the later stages of COPD?
The later stages of COPD are characterised by the development of respiratory failure.
For practical purposes this is said to occur when there is either a PaO2 <8 kPa (60 mmHg) or a PaCO2 >7 kPa (55 mmHg).
What is one of the complications in late-stage COPD?
Cor pulmonale
What is cor pulmonale?
Patients with advanced COPD may develop cor pulmonale, which is defined as symptoms and signs of fluid overload secondary to lung disease.
The fluid retention and peripheral oedema is due to failure of excretion of sodium and water by the hypoxic kidney rather than heart failure.
What is cor pulmonale characterised by?
It is characterised by pulmonary hypertension and right ventricular hypertrophy.
Initially there may be a prominent parasternal heave, due to right ventricular hypertrophy, and a loud pulmonary second sound.
In very severe pulmonary hypertension, the pulmonary valve becomes incompetent.
What are late-stage complications of fluid overload secondary to cor pulmonale?
With severe fluid overload, tricuspid incompetence may develop with a greatly elevated jugular venous pressure (JVP), ascites and upper abdominal discomfort due to liver swelling.
How is a COPD diagnosis made?
Usually based on history of:
- Breathlessness
- Sputum production
- Chronic smoking
In absence of smoking, asthma is a more likely diagnosis, unless there is a family history of alpha-antitrypsin deficiency
No individual clinical feature is diagnostic. Patient may have signs of:
- Hyperinflation
- Pursed lips respiration
- Barrel chest
What investigations are appropriate for suspected COPD?
- Lung function test (FEV1: FVC <0.7)
2. Chest X-ray (often normal)
What is the management of COPD?
- Smoking cessation!
2. Drug therapy
What is the drug therapy pathway for people with COPD?
- SABA or SAMA
2A. IF FEV >50% and no asthmatic features then LABA + LAMA
2B. IF FEV < 50% and asthmatic features, then LABA +ICS
- LABA + LAMA + ICS
Name a sama
ipratropium
Name a lama
tiotropium
What is the mechanism of action for LAMA or SAMAs?
Inhibition of the M3 muscarinic receptors in the smooth muscle of the lungs leads to relaxation of smooth muscle and bronchodilation
What dose tiotropium would you prescribe?
5 micrograms once daily inhaled
What dose ipratropium would you prescribe?
Nebulised 250-500 micrograms, 3-4 times a day
What corticosteroid would you give COPD patients?
Prednisolone 30 mg daily should be given for 2 weeks, with measurements of lung function before and after the treatment period
What is the use for antibiotics in COPD?
Prompt antibiotic treatment shortens exacerbations and should always be given in acute episodes as it may prevent hospital admission and further lung damage
What are features suggestive of an acute exacerbation of COPD?
Worsening breathlessness.
Increased sputum volume and purulence.
Cough.
Wheeze.
Fever without an obvious source.
Upper respiratory tract infection in the past 5 days.
Increased respiratory rate or heart rate increase 20% above baseline.
What are symptoms associated with a severe acute exacerbation in COPD?
Marked breathlessness and tachypnoea.
Pursed-lip breathing and/or use of accessory muscles at rest.
New-onset cyanosis or peripheral oedema.
Acute confusion or drowsiness.
Marked reduction in activities of daily livi
What investigations would you do for a suspected exacerbation of COPD?
Check vital signs (including temperature, oxygen saturations [using pulse oximetry], blood pressure and heart rate).
Assess for confusion or impaired consciousness.
Examine the chest.
Check ability to cope at home.
What O2 would you use for COPD patients?
Venturi 24% mask at 2-3 l/min or Venturi 28% mask at a flow rate of 4 l/min or nasal cannula at a flow rate of 1-2 l/min (if a 24% mask is not available).
What is the target O2 saturation for patients with COPD?
88-92%
