COPD Flashcards
How common is COPD?
In the UK, it is estimated that more than 3 million people currently have chronic obstructive pulmonary disease (COPD), with the disease being undiagnosed in about 2 million of these people.
Who is affected by COPD?
Smokers - usually >50yo
More common in men than women
What is the pathophysiology COPD?
COPD = chronic bronchitis + emphysema
The two disease are quite distinct and have different aetiologies, but together form COPD.
COPD has both pulmonary and systemic components. The presence of airflow limitation, combined with premature airway closure, leads to gas trapping and hyperinflation, reducing pulmonary and chest wall compliance. Pulmonary hyperinflation also flattens the diaphragmatic muscles and leads to an increasingly horizontal alignment of the intercostal muscles, placing the respiratory muscles at a mechanical disadvantage. The work of breathing is therefore markedly increased, first on exercise, when the time for expiration is further shortened, but then, as the disease advances, at rest.
Emphysema may be classified by the pattern of the enlarged airspaces as centriacinar, panacinar or paraseptal. Bullae form in some individuals. This results in impaired gas exchange and respiratory failure.
What risk factors are there, and how can they be reduced?
- Smoking (95% cases) - cessation
- Indoor air pollution; cooking with biomass fuels in confined areas in developing countries
- Occupational exposures, such as coal dust, silica and cadmium
- Low birth weight may reduce maximally attained lung function in young adult life
- Lung growth: childhood infections or maternal smoking may affect growth of lung during childhood, resulting in a lower maximally attained lung function in adult life
- Infections: recurrent infection may accelerate decline in FEV1; persistence of adenovirus in lung tissue may alter local inflammatory response, predisposing to lung damage; HIV infection is associated with emphysema
- Low socioeconomic status
- Cannabis smoking
- Genetic factors: α1-antiproteinase deficiency; other COPD susceptibility genes are likely to be identified
- Airway hyper-reactivity
What is the presentation of COPD?
- COPD should be suspected in any patient over the age of 40 years who presents with symptoms of chronic bronchitis and/or breathlessness. Important differential diagnoses include chronic asthma, tuberculosis, bronchiectasis and congestive cardiac failure.
- Cough and associated sputum production are usually the first symptoms, often referred to as a ‘smoker’s cough’. Haemoptysis may complicate exacerbations of COPD but should not be attributed to COPD without thorough investigation.
- Breathlessness usually precipitates the presentation to health care. The severity should be quantified by documenting what level of exertion the patient can manage before stopping
- In advanced disease, enquiry should be made about the presence of oedema, which may be seen for the first time during an exacerbation, and morning headaches, which may suggest hypercapnia.
What symptoms should you look out for?
- Productive cough
- Breathlessness
- Morning headache
- Decreased exercise tolerance
- Frequent chest infections
What signs may the patient have on examination?
Signs correlate poorly with lung function and are non-specific
- Breath sounds typically quiet
- Crackles my accompany infection (but if persistant may point to bronchiectasis)
- Finger clubbing NOT a symptom of COPD
- Pitting oedema due to cor pulmonale
- Hyperexpansion of chest
- CO2 flap
What other conditions might present in a similar way?
Asthma
Congestive heart failure
Bronchitis
Emphysema
How would you investigate this patient?
Bedside tests
- peak flow
Other
- spirometry (post-bronchodilator FEV1/FVC of less than 70%)
- CXR
What would you tell the patient and how would you explain the condition to them?
Chronic obstructive pulmonary disease (COPD) is the name for a group of lung conditions that cause breathing difficulties.
It includes:
emphysema – damage to the air sacs in the lungs
chronic bronchitis – long-term inflammation of the airways
COPD is a common condition that mainly affects middle-aged or older adults who smoke. Many people don’t realise they have it.
The breathing problems tend to get gradually worse over time and can limit your normal activities, although treatment can help keep the condition under control.
How do you think the patient and/or family might be affected by the diagnosis? Will it affect their ability to work/care for themselves?
It has the potential to have a profound effect on the patient’s life/work/family. It can cause significant morbidity and is likely to be life-limiting. Lifestyle changes are essential in management.
What questions are they likely to have?
Is is curable? Is it life-limiting? Will I still be able to work? Is it progressive? Is it reversible? What can be done to halt its progression.
What pharmacological treatments would you discuss with the patient? What are the risks and benefits?
Mild - active reduction of lifestyle factors, ‘flu vaccine, short-acting beta2 agonist PRN
Moderate - Add regular treatment with one or more long-acting bronchodilators PRN and rehabilitation
Severe - Add inhaled glucocorticoids
Very severe - Add long-term O2 if in chronic resp. failure, consider surgical treatments
Benefits - amelioration of symptoms, improved QoL and ability to perform tasks of daily living
Risks - certain long-acting bronchodilators can cause paroxysmal bronchospasm, tolerance etc. Glucocorticoids can cause oral candidiasis etc. 02 therapy can be very inconvenient
What non-pharmacological treatments would you discuss with the patient? What are the risks and benefits?
Lifestyle changes
e. g. smoking cessation, occupational considerations etc
- Benefits - slows/halts progression of disease
- Risks - inconvenience (change of job etc)
Pulmonary rehabilitation
e.g. exercise encouraged at all stages - pt. encouraged that while distressing, breathlessness is not life-threatening
What surgical treatments would you discuss with the patient? What are the risks and benefits?
Bullectomy - patients in whom large bullae compress surrounding normal tissue, who otherwise have minimal flow limitation and lack of generalized emphysema
Lung volume reduction surgery - patients with predominantly upper lobe emphysema, with preserved gas transfer and no evidence of pulmonary hypertension may benefit.
What other healthcare professionals may be involved in their care?
Physiotherapists
Occupational therapists
Specialist nurses
What is emphysema?
Structural changes arising from alveolar destruction result in a loss of elastic recoil and loss of outward traction on the small airways such that they collapse on expiration, contributing to obstruction, air trapping and hyperinflation. There is also a loss of surface area to volume ratio for O2/CO2 exchange ->hypercapnia and hypoxaemia.
What is chronic bronchitis?
Hypersecretory disorder defined as the presence of cough productive of sputum on most days for at least 3 months of 2 successive years
What pulmonary changes can be observed in COPD?
- Enlargement of mucus-secreting glands and increase in number of goblet cells, accompanied by an inflammatory cell infiltrate, result in increased sputum production leading to chronic bronchitis.
- Pulmonary vascular remodelling and impaired cardiac performance
- Loss of elastic tissue, inflammation and fibrosis in airway wall result in premature airway closure, gas trapping and dynamic hyperinflation leading to changes in chest wall and pulmonary compliance
- Unopposed action of proteases and oxidants leading to destruction of alveoli and appearance of emphysema
What systemic changes can be observed in COPD
- Muscular weakness reflecting deconditioning and cellular changes in skeletal muscle
- Increasing circulating inflammatory markers
- Impaired salt and water excretion leading to peripheral oedema
- Altered fat metabolism contributing to weight loss.
- Increased prevalence of osteoporosis
