- Signs and symptoms
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- Bronchitis – Cough and sputum production on most days for at least 3 months during the last two years.
- Emphysema – Enlarged airspaces distal to the terminal bronchioles, with destruction of the alveolar walls.
- Previously patients were often diagnosed with “chronic bronchitis” or “emphysema” – often dependent on their clinical symptoms. However, it is now best practice to avoid using the terms, and instead to use the diagnosis of COPD
- COPD should be distinguished from the other main form of chronic respiratory disease – the restrictive pulmonary diseases. These are a group of disorders characterised by decreased lung capacity where FEV1 and FVC are both decreased proportionately, resulting in a normal FEV1:FVC.
- See restrictive vs obstructive lung disease for more information
In COPD the FEV1:FVC ratio is <70%. COPD can also be diagnosed in patients with FEV1:FVC ratio is >70% on the basis of clinical signs and symptoms – such as shortness of breath, or cough.
Patients typically follow a slowly progressive course, with recurrent “exacerbations”.
Long term management often involves combinations of inhaled steroids and bronchodilators, smoking cessation and pulmonary rehabilitation. It is also important to prevent exacerbations with flu and pneumonia vaccination.
Exacerbations are often mild and can be treated in primary care, but COPD also frequently present to hospital with exacerbations. Treatment of exacerbations typically involves oral steroids, increases in doses of inhaled agents, oxygen therapy and in many (but not all cases) antibiotics.
Severe long-term cases may result in the use of home oxygen therapy.
- Prevalence of about 1.5m in the UK
- Mortality is 23,000 /year in the UK
- It is severely under-diagnosed. Airway obstruction affects 10% off the UK population, but only about 4% of these are diagnosed with COPD – i.e. 40-60% of patients are undiagnosed
- The 4th highest cause of death world-wide – and soon likely to be the 3rd
- Smoking accounts for 90-98% of all cases
- Symptoms will improve in 90% of patients with smoking cessation
- Number of cases has stabilised in men, but is rising among women
- Most commonly seen in ex-smokers > 35 years of age
- Most patients done show symptoms until in their 50s
- COPD is unlikely to develop with a smoking history less than 10 pack years
- The number of deaths from COPD each year has been greatly reduced from 200 per 100 000, to 70 per 100 000 in the last 25 years
- It is responsible for 1 in 8 hospital admissions
- 25% of patients will die within the first 5 years of diagnosis
- Associated with other co-morbidities: cardiovascular disease, lung cancer, osteoporosis, depression
- 10 – 20% of all smokers will develop COPD
- Up to 50% of those with a >20 pack year smoking history will get COPD
- Coal mining
- Exposure to air pollution – particularly from indoor fires and cooking in the developing world
- Genetic, i.e. α1 –antitrypsin deficiency causes emphysema
- Low socioeconomic status and low birth weight are predisposing factors
- Low birth weight is associated with reduce maximum lung capacity in adulthood
- Asthma and COPD may also co-exist
Signs and symptoms
- Breathlessness (dyspnoea)
- Cough – may or may not be productive (just normal sputum)
- Regular exacerbations
- Use of accessory muscles of respiration
- Reduced cricosternal distance (<3cm) – this is the distance between the cricoid cartilage and the sternal angle – this is reduced because of hyperinflation – thus the thorax is raised in relation to the cricoid cartilage.
- Reduced chest expansion
- Resonant chest sounds – suggestive of hyperinflation
- Quiet breath sounds – over areas of emphysematous bullae
- Wheeze – this is an abnormal high pitched or low pitched breath sound heard on expiration. Often a wheeze is polyphonic- this means it is made up of many different notes, and thus this shows it is caused by many abnormal airways. Wheeze is normally caused by abnormal small airways. A monophonic wheeze is caused by a single airway obstruction, and is more likely to be cancer.
- Stridor is the name for a wheeze heard on inspiration. It is caused by abnormal large airways – and thus not normally heard in COPD. It is more likely to be heard in cancer.
- Cor pulmonale
- Prolonged expiration – because their FEV1 is low, they have to have a prolonged expiratory phase to allow for adequate respiration.
- Pursed lip breathing – This is a technique that many COPD patients adopt by themselves, but it is also taught in pulmonary rehab clinics. It will reduce the respiratory rate, as well as helping some areas of trapped air in the lungs. There is evidence to suggest it reduces dyspnoea. The respiratory rate is reduced because it just physically reduces the opening of the airway to a small size, and thus exchange of air across the opening is a slow process. This also creates an area of high pressure at the pursed lips themselves, and this high pressure will mean that the dynamic closure point is moved to a more distal area of the lung. In COPD, some of the airways will collapse at a point proximal to many of the alveoli – this point is known as the dynamic closure point. I presume this occurs due to the destruction of elastin tissue that occurs in emphysema. Anyway, pursed lip breathing keeps the pressure in the lungs higher, and thus the closure point is kept open, and thus ventilation can occur in a greater number of alveoli (more alveoli are ‘recruited’), and the VQ mismatch is reduced.
- Lung function tests (spirometry)
- FVC<80% predicted
- FEV1/FVC<0.7, OR <LLN (lower limit of normal)
- Increased residual volume
- Possibly hyperinflation, but often normalF
- Flat hemidiaphragms
- Large central pulmonary arteries
- Decreased peripheral vascular markings
- Cylindrical heart
- Right atrial and ventricular hypertrophy suggestive of cor pulmonale, leading to large p waves on ECG →p pulmonale
- ABG – often normal, but in advanced disease, there may be:
- Decreased PaO2
- Increased PaCO2
- Full Blood Count
- Polycythaemia – measure the haematocrit – >45
- Normocytic normochromic anaemia of chronic disease – prevalence of up to 20%.
- HB and PCV may be raised
- Tests for α1-antitrypsin
- Gas transfer – reduced
This is a test to measure the effectiveness of gas transfer across the alveoli. Requires a known Hb value for calibration The patient inhales a known value of carbon monoxide (which has a very high affinity for haemoglobin – higher even than oxygen). In emphysema and severe fibrosis, the gas transfer value is reduced.
0 – at risk
I – Mild
II – Moderate
Mild to moderate
III – Severe
IV – very severe
- If there is no history of cigarette smoking then a tentative diagnosis of asthma is usually given instead of COPD. UNLESS, there is also a family history of lung disease suggestive of α1- antitrypsin deficiency.
- There are no clinical features that are diagnostic. Be wary of giving a diagnosis of emphysema just on the basis of hyperinflation. Asthma may also cause this. Also be aware that in elderly patients, there may appear to be a barrel chest, but in actual fact, it is just curvature of the spine as a result of osteoporosis.
Differentiating COPD and asthma
Age of onset >35
Age of onset <35
No diurnal variation in FEV1
Diurnal variation in FEV1
No sputum produced
History of many years of smoking
(generally patients too young to have this)
- Hypersecretion of mucus due to marked hypertrophy of mucus-secreting glands and hyperplasia of goblet cells. Reduces lumen size and increasing distances for gas diffusion
- Abnormal dilation of air spaces with destruction of alveolar walls
- Inflammation and scarring, reducing size of lumen of airways and reducing lung elasticity
- Initially small airways are affected and this initial inflammation is reversible, whereas in later stages larger airways become affected and the process is no longer reversible
- Epithelial layer becomes ulcerated and squamous epithelium may be replaced by columnar cells, resulting in increased gas diffusion distance
Defined as cough and sputum production on most days for at least 3 months during the last two years.
- An enlargement in mucus secreting glands (hypertrophy)
- An increased number of goblet cells (hyperplasia)
- Loss of elasticity of the alveoli
- Inflammation and scarring – reducing the size of the lumen, as well as reducing elasticity
- Mucus hypersecretion – reducing the size of the lumen and increasing the distance gasses have to diffuse.
Pink Puffers and Blue Bloaters
- Pink Puffers – have a near normal PaO2, and a normal or low PaCO2 (due to hyperventilation). They ‘puff’ to increase their alveolar ventilation – and by doing so they are able to keep their blood gas values normal. These patients generally have emphysema or at least a higher degree of emphysema than bronchitis. These are likely to enter type I respiratory failure.
- Blue Bloaters – these have decreased alveolar ventilation. They have a low PaO2 and a high PaCO2. They are cyanosed but not breathless (because their respiratory centre has become sensitised). They rely on hypoxic drive to maintain adequate ventilation. They often go on to develop cor pulmonale. These patients are more likely to be type II respiratory failure. ‘Bloater’ – due to cor pulmonale.
- Streptococcus pneumoniae – this is a Gram-positive diplococcus.
- Haemophilus influenzae – this is a Gram-negative coccobascillus.
- Oxygen therapy – beware of CO2 retention
- Give controlled O2 therapy to maintain sats at 88-92%
- Perform repeat ABGs (e.g. every 20 minutes) to assess for a rise in PaCO2
- If PaCO2 has risen > 1.5kPa consider use of CPAP or other assisted ventilation
- PaCO2 is dependent on VENTILATION – i.e. the volume of air inhaled and exhaled
- PaO2 is dependent on alveolar gas transfer (“OXYGENATION”) and the percentage of oxygen inhaled
- VENTILATION and OXYGENATION are not the same!
- In COPD, the normal respiratory drive, (usually driven by PaCO2) is not longer effective – the feedback mechanism between respiratory rate and PaCO2 has been lost. So, a patient may be adequately oxygenating due to the quality of O2 inhaled, but may not be adequately ventilating to “blow off” CO2
- Rising PaCO2 can lead to reduced level of consciousness and is a poor prognostic factor
- Give nebulised salbutamol (2.5-5mg in solution), and ipratropium (0.5mg)
- Repeat doses as required
- Give steroids – typically 50mg OD for 5-7 days
- Treat the cause
- Could be viral
- Not all exacerbations need antibiotics
- If bacterial, most common causes are Streptococcus pneumonia or Haemophilus influenza
Management of long-term disease
- Smoking cessation – whatever stage the disease, this can slow down the progression
- Long-term oxygen therapy – give 2L via nasal prongs for at least 15 hours per day
- Known as LTOT – long term oxygen therapy
- Smoking cessation and LTOT are the only two things that can prolong the life expectancy in COPD.
- Pulmonary rehabilitation
- Drugs – salbutamol, ipratropium
- Surgery, i.e. bullectomy in those who have large emphysematous bullae, or lung transplant in those with end-stage emphysema.
- Exercise training
- Diet – to promote weight gain if weight loss experienced
Drugs – in many cases these are similar to those used in asthma, despite the fact that on paper, it appears they shouldn’t work. However, in practice, many patients get great symptom relief from these drugs:
- Short acting beta agonist or anti-cholinergic – i.e. salbutamol – 200μgevery 4-6 hours
- Long acting beta agonist or anti-cholinergic – i.e. ipratropium – 40μg 4x a day
Steroids – a trial of these is indicated in virtually any patient with symptoms. The trial is typically 40mg prednisolone for 2 weeks. If the trial increases the FEV1 by >15% then you should prescribe a long term inhaled corticosteroid – i.e. beclomethasone – 400μg twice daily. If there is no response in the trial, then there is no point giving the inhaled corticosteroid.
- The long-term effectiveness of these drugs is yet to be established.
Antibiotics – these should be given promptly during exacerbations, as they reduce the duration of the exacerbation, and prevent hospital admission and further lung damage.
- Patients are sometimes given their own supply of antiobiotics to keep at home, and instructed to take them as soon as their sputum turns yellow or green. They are NOT FOR PROPHYLAXIS!
- However – there is some new evidence emerging that long term AB therapy can preserve lung function, as lung function may be lost during exacerbations.
- Note that about 10-20% of H influenzae is now amoxicillin resistant – although this is not a major problem, as co-amoxiclav is a very useful alternative drug.
Diuretics – these are often also taken by many patients (I presume due to the secondary cor pulmonale)
- Only 30% of those not receiving LTOT survive more than 5 years after diagnosis.
- By giving the LTOT you reduce the pulmonary arterial pressure. Moderate reduction is pressure is achieved after 15 hours, and a larger reduction after 19 hours a day.
Indications for LTOT
- PaO2 <7.3kPa
- PaO2 <8kPa, and patient also has polycythaemia, hypoxaemia, peripheral oedema or pulmonary hypertension
- FEV1 30-49% predicated
- Any of the indications above
- Some patients who have a large emphysematous bullae may benefit form a bullectomy. This enables adjacent areas of collapsed lung to re-expand into the space, and function again. This improves VQ mismatch.
- Another option – you can put a valve in on bronchoscopy – this will allow air out of an emphysematous bullae, but not allow air in, and this eventually allows the bullae to collapse.
- Another option is lung volume reduction surgery. This aims to increase the elastic recoil of the lung. Patients have to be carefully selected, and have an FEV1 <1L. it improves symptoms, but does not improve mortality.
- Lung transplant can be performed on certain patients with end stage emphysema. It has a 3-year survival of 75%, and again, the treatment improves symptoms, but does not really affect quality of life.
Weight loss and COPD
- Cardiac output will be normal or slightly increased
- Salt and fluid retention will occur as a result of renal hypoxia
- Technically, respiratory failure occurs when the PaO2 <8kPa, or the PaCO2 >7kPa.
Type one respiratory failure
- Pulmonary oedema
- Fibrosing alveolitis
- Treat the underlying cause
- Give O2 (35-60%) by face mask to correct the hypoxia
- If PaO2 does not rise above 8kPa then give assisted ventilation
Type two respiratory failure
- Pulmonary disease (COPD, asthma, pulmonary fibrosis, obstructive sleep apnoea)
- Reduced respiratory drive – can be a result of sedentary drugs, trauma or CNS tumour
- Neuromuscular disease – e.g. cervical cord lesion, diaphragmatic paralysis, polio, myasthaenia gravis
- Thoracic wall disease
- Give controlled oxygen therapy, starting at 24% O2
- Recheck the ABG after 20 minutes – if the PaCO2 is steady or lower, then you can increase the O2 to 28%.
- If the PaCO2 has risen >1.5kPa– then consider giving a respiratory stimulant such as doxapram (1.5-4mg/min IV) or assisted ventilation.
- You can also see CO2 retention as physical signs – the patient will become drowsy and confused
- If this fails consider intubation / ventilation
- This is right sided heart failure, as a result of pulmonary hypertension
- The patient is likely to be cyanosed – look at the hands!
- They are also likely to have ankle oedema and ascites due to fluid retention
- Likely to have severe breathlessness
- There may be an especially loud pulmonary heart sound, and there may be a diastolic murmur, as a result of incompetence of the pulmonary valve.