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The importance of an early diagnosis in COPD patients

The importance of an early diagnosis in COPD patients

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory condition of the airways characterised by persistent airflow obstruction.1 In contrast to asthma where the airway inflammation leads to variable airflow obstruction, the airflow obstruction in patients with COPD is usually irreversible and progressive.

COPD is expected to become the third most common cause of morbidity and mortality worldwide by 2020. In the UK the prevalence of COPD has been estimated at around 2%, but this is most likely underestimated as many patients complaining of respiratory symptoms remain undiagnosed in primary care.2 

Aetiology and pathophysiology
Cigarette smoking is the most important risk factor for the development of COPD. In developing countries, the burning of indoor biomass cooking fuels is being recognised as a significant risk for the disease. Other factors include: passive smoking, genetics (eg. alpha-1 anti-trypsin deficiency), environmental air pollution, occupational exposures (eg. coal mine workers), childhood respiratory illness (which predisposes to chronic adult disease), recurrent bronchopulmonary infections, and chronic asthma.
Airway inflammation.
Mucus gland hyperplasia.
Airway fibrosis. 
Emphysema with alveolar wall destruction of the alveolar walls.

Making the diagnosis
COPD should be considered in patients >35 years of age who are current or ex-smokers and who are short of breath on exertion, have sputum production or a chronic cough. Exercise tolerance should be assessed using the Medical Research Council Dyspnoea Scale (see Table 1) together with a record of activities of daily living and how these have changed over the past years.
‘Pack-years’ (one pack year = 20 cigarettes smoked per day for one year) should be calculated as there is a clear relationship between the risk of COPD and the amount smoked. Direct questions about other symptoms may reveal associated comorbidities; haemoptysis and weight loss (possible lung carcinoma), ankle oedema or chest pain (concomitant cardiac disease) and nocturnal wakening (sleep-related disorder). The frequency of disease exacerbations (antibiotic courses, hospital admissions) in the last year should also be recorded.

Abnormal signs are usually present in acute exacerbations, but in stable disease attention should be paid to nicotine-stained fingernails, clubbing and lymphadenopathy (associated lung carcinoma), anaemia, bounding pulse (carbon dioxide retention), raised jugular venous pressure and ankle oedema (right ventricular failure, pulmonary hypertension). Hyperinflated lungs, indrawing of the intercostal muscles and pursed lips breathing are important signs. Breath sounds may sometimes be difficult to hear.

Airflow obstruction is defined as an FEV1 (forced expiratory volume in one-second) less than 80% predicted and an ‘obstructive’ FEV1/FVC ratio of less than 70% (where FVC is forced vital capacity). In COPD there is usually poor bronchodilator reversibility; that is, 20 minutes after inhaling a short-acting beta-2-agonist (eg. 400μg salbutamol) the change in FEV1 is less than 15% compared to baseline values.

Pulse oximetry
Finger pulse oximetry is useful in primary care to monitor oxygenation levels in stable patients with COPD, especially when assessing patients who may need long-term oxygen therapy (LTOT). Oxygen saturations ≤92% at rest indicate an outpatient hospital evaluation for oxygen therapy.

Sputum analysis
Patients who regularly expectorate sputum should have samples sent off for microbiological analysis including culture and antibiotic sensitivities.

Supporting investigations
Patients should have their body mass index (BMI) assessed, especially if there is weight loss, blood tests for anaemia or polycythaemia (secondary to hypoxaemia) and a chest radiograph undertaken (to exclude other pathology). Testing for alpha-1-antitypsin deficiency should be undertaken, especially in young people (<50 years) with a minimal smoking history.

Classification of severity
The severity of COPD has usually been graded on the degree of lung function impairment as a percentage of the predicted FEV1, where National Institute of Health and Care Excellence (NICE) and/or British Thoracic Society (BTS) guidelines grade COPD disease severity as mild (FEV1 50-80%), moderate (FEV1 30-49%) or severe (FEV1<30%).3 
The recent 2011 COPD GOLD guidelines propose a new system of COPD assessment that incorporates:
Symptoms and/or health status using the modified Medical Research Council Dyspnoea Scale (mMRC) and the eight-question COPD Assessment Tool (CAT), where an mMRC score of >2 or a CAT score of >10 is indicative of high impact of symptoms; and
Future risk determined by the GOLD classification of degree of airflow limitation and patients’ exacerbation history, where severe/very severe patients (GOLD three and four) or those with >2 exacerbations in the previous year confer a high risk group.1 Disease exacerbations are associated with an increased rate of decline in lung function, morbidity and mortality.

Treating the condition
Multidiciplinary team
A multidisciplinary approach is necessary in managing patients with COPD in the community and incorporates strategies of smoking cessation, pharmacotherapy, long-term oxygen therapy, nutritional supplementation, and pulmonary rehabilitation. An annual influenza vaccination and pneumococcal vaccination should be offered to all patients with COPD. It should be appreciated that anxiety and depression can co-exist in COPD patients that may worsen their perception of breathlessness and simple questionnaires may help screen out such patients in primary care in addition to the clinical history.

Smoking cessation
Smoking cessation advice should be undertaken at every opportunity to patients that continue to smoke. Smoking cessation programs combine pharmacological treatments with psychosocial support to overcome the nicotine cravings and the drugs available are bupropion, varenicline and nicotine replacement therapies (chewing gum, inhalation, patches and tablets). The Royal College of Physicians have recently updated their policy on the use of e-cigarettes on their website.

These are first line agents for patients with COPD and include inhaled beta-2-agonists (short- and long-acting), inhaled anti-muscarinics (short- and long-acting) and oral methylxanthines. They help control the symptoms of breathlessness and wheeze in patients. Combining bronchodilator drugs that have different pharmacological properties may result in additional bronchodilation and improved symptom control. Inhaler technique should be checked at every opportunity.

Inhaled corticosteroid (ICS) monotherapy does not affect the rate of decline in lung function in patients with COPD, however ICS combination with long acting beta-agonists (LABA) have been shown to reduce disease exacerbations and improve quality of life.4 NICE guidelines recommend inhaled ICS-LABA combinations are used in patients with FEV1 <50% predicted and with >2 exacerbations per year. Recent data suggest ICS use may be associated with an increased risk of pneumonia and this association needs to be directly addressed in future research. Oral corticosteroids are usually prescribed in disease exacerbations, where they improve lung function and gas exchange and help towards the resolution of the exacerbation, but they are associated with systemic adverse effects and therefore used for five to seven days.

Long-term oxygen therapy (LTOT)
COPD patients may become progressively hypoxaemic with disease progression, leading to a decreased exercise capacity. Long-term oxygen therapy (LTOT) for >15 hours a day increases survival in COPD patients with chronic respiratory failure and is prescribed in stable patients who have a PaO2 <7.3 kPa, which corresponds to arterial oxygen saturations SaO2 <88%. Patients with a PaO2 between 7.3-7.8 kPa at rest and right ventricular failure secondary to lung disease may also benefit from LTOT. Active smoking is contraindicated with oxygen therapy, but some patients continue to smoke on LTOT and the effects of oxygen treatment on this group of patients remains unknown. 
Supplemental as-needed oxygen therapy can sometimes be used in patients who have arterial desaturations that are exercise-induced or in those who have episodic breathlessness, activity-limiting dyspnoea or in the palliative care of end-stage disease. 
Diuretics may often be helpful in controlling peripheral ankle oedema in patients with right heart failure secondary to lung disease.

Pulmonary rehabilitation (PR)
PR involves a multidisciplinary approach with interventions tailored to individual patient’s needs that include:
Disease education.
Nutritional advice.
Drug management.
Physical training.
Psychosocial support. 
PR has been demonstrated to provide improvements in dyspnoea, exercise performance and health status and may have an economic health benefit by reducing disease exacerbations and hospital admissions.5 

Not uncommon as in the general population, patients with COPD may have a high BMI and should be referred for dietary advice. Particular dietary attention should be given to those with a low BMI to increase their daily intake of calories.

Mucolytics and anti-tussives
Mucus hypersecretion and sputum retention in the airways can contribute to COPD, however there is little data to support regular mucolytic therapy.1 Antitussive treatments such as codeine should be avoided as opiates can decrease the respiratory drive. They may, however, be helpful in the palliative care of the breathless patient with end-stage COPD.

Managing COPD in primary care
A late diagnosis of COPD poses a problem as the disease may be rather advanced before the cause of the patient’s respiratory problems are diagnosed. Primary care can play a very important role in helping an early diagnosis of the COPD with timely use of spirometry to assess a patient with breathlessness, exertional dyspnoea or persistent cough. Most patients with COPD are managed in the community and often prefer to be treated at home when they have a disease exacerbation. Hospital-at-home schemes reduce hospital admissions and involve a multi-disciplinary team overseeing the assisted-discharge and rehabilitation of a patient into the community. Patients may benefit from a variety of patient groups that provide an environment for informal discussions in a supportive atmosphere for patients with chronic lung conditions. Patients with end-stage disease should have access to palliative care services and healthcare professionals should engage with patients when they are stable regards end-of-life decisions; for example, regarding mechanical ventilation in the event of further deterioration. Palliation of breathlessness in terminal illness is extremely important and palliative care physicians and nurses can provide valuable support.

A clinical diagnosis of COPD should be considered in any  patient in primary care who has dyspnoea, chronic cough or sputum production and/or a history of exposure to risk factors 

for the disease.

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