18 COPD
An Update on the Diagnosis and Management of COPD Written by P.C. Ridge; S.M. Walsh Department of Respiratory Medicine, University Hospital Galway, Ireland | National University of Ireland, Galway Correspondence: Dr Padraic Ridge, Department of Respiratory Medicine, Galway University Hospitals, Galway, Ireland E mail: p.macaniomaire1@gmail.com Assessment of a patient with suspected COPD The three main symptoms of COPD are dyspnoea, chronic cough, and sputum production. The first and most common symptom reported by patients is dyspnoea on exertion. Less commonly, patients describe symptoms of wheeze, fatigue and anorexia.
Dr Padraic Ridge
Introduction Chronic obstructive pulmonary disease (COPD) is a common condition characterised by persistent respiratory symptoms with non-variable airways disease (obstruction) and/or alveolar damage (emphysema). It is caused by significant exposure to noxious gases or particles.1 In this article, we review the disease pathogenesis, epidemiology, approach to assessment, diagnosis and chronic disease management for a patient. Pathogenesis Cigarette smoke is the most common risk factor for COPD worldwide, accounting for approximately 80% of cases. Pipe tobacco and marijuana are other risk factors.1 Passive exposure to cigarette smoke can also lead to COPD by increasing the total burden of inhaled particles and gases that the lungs are exposed to. Other causes include burning of biomass fuels, air pollution and occupational exposures, including those experienced by sculptors and gardeners.2 Interestingly, not all individuals who smoke will develop COPD. Even in those who are heavy smokers, less than 50% will develop COPD during their lifetime.3 This variability is believed to be due to a complex interplay between the type and intensity of noxious exposures and individual factors such as genetics, age, gender, airway
The key findings on clinical examination of a patient with COPD are usually absent until significant impairment of lung function has occurred.8 Tachypnoea occurs Dr Sinead Walsh with activity, with increasing respiratory rate in proportion to disease severity. Use of hyper-responsiveness, infections available on accessory requestrespiratory muscles andReferences overall lung development and paradoxical indrawing of the 1, 4, 5 in childhood. lower intercostal spaces (Hoover sign) indicates airway hyperinflation Epidemiology and a flattened diaphragm. Other findings on thoracic The prevalence of COPD is examination include a barrel chest, increasing worldwide and is hyperresonance on percussion, expected to continue to rise due diffusely decreased breath sounds, to ongoing exposure to COPD and prolonged expiration. risk factors, particularly smoking, in developing countries and an Diagnosis and staging aging population in developed 3, 6 countries. The global burden Diagnosis of COPD is based on of disease study reported COPD a triad of causative exposure, FIGURE 1: cause of as the third leading symptoms and spirometry. death worldwide.7 The estimated Spirometry is the most worldwide COPD mean prevalence reproducible and objective is 13.1%, however data in many measurement of airflow limitation.1 It measures the volume of air that a geographic areas is scarce.4, 6
Figure 1
FIGURE 2:
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patient can forcibly exhale from the point of maximal inspiration (forced vital capacity, FVC) and the volume of air that is exhaled during the first second of this manoeuvre (forced expiratory volume in one second, FEV1). The ratio of the FEV1/FVC is calculated. Airflow obstruction is a post-bronchodilator FEV1/FVC ratio less than 70%. At diagnosis patients should have the severity of their airflow limitation classified according to the GOLD (Global Initiative for Chronic Obstructive Lung Disease) guidelines. This classifies patients with a FEV1/ FVC ratio less than 70% into four categories (GOLD 1 – 4), based on their FEV1 value (FIGURE 1). Symptom burden should be assessed using the mMRC (Modified British Medical Research Council questionnaire) or the CAT (COPD Assessment test). An assessment of exacerbation risk should also occur. A COPD exacerbation is an acute worsening of respiratory symptoms that results in additional therapy.9 Exacerbations can be classified as mild, moderate or severe. The best predictor of having frequent exacerbations (defined as two or more exacerbations in one year) is a history of previous exacerbations.10 Using these variable individuals may be classified as GOLD A – D1
