Chronic Obstructive Pulmonary Disease (COPD) is a common, preventable and treatable disease that is characterized by persistent respiratory symptoms and airflow limitation that is due to airway and/or alveolar abnormalities usually caused by significant exposure to noxious particles or gases and influenced by host factors including abnormal lung development. Significant comorbidities may have an impact on morbidity and mortality. There may be significant lung pathology (e.g., emphysema) in the absence of airflow limitation that needs further evaluation
WHAT CAUSES COPD?
Worldwide, the most encountered risk factor for COPD is tobacco smoking. Nonsmokers may also develop COPD. COPD is the result of a complex interplay of long-term cumulative exposure to noxious gases and particles, combined with a variety of host factors including genetics, airway hyper-responsiveness and poor lung growth during childhood. The risk of developing COPD is related to the following factors:
Tobacco smoke – cigarette smokers have a higher prevalence of respiratory symptoms and lung function abnormalities, a greater annual rate of decline in FEV1, and a greater COPD mortality rate than nonsmokers.6Other types of tobacco (e.g., pipe, cigar, water pipe) and marijuana are also risk factors for OPD, as well as environmental tobacco smoke (ETS).
Indoor air pollution – resulting from the burning of wood and other biomass fuels used for cooking and heating in poorly vented dwellings, is a risk factor that particularly affects women in developing countries.
Occupational exposures – including organic and inorganic dusts, chemical agents, and fumes, are under appreciated risk factors for COPD.
Outdoor air pollution – also contributes to the lungs’ total burden of inhaled particles, although it appears to have a relatively small effect in causing COPD.
Genetic factors – such as severe hereditary deficiency of alpha-1 antitrypsin (AATD) the gene encoding matrix metalloproteinase 12 (MMP-12) and glutathione S-transferase have also been related to a decline in lung function or risk of COPD.
Age and sex – aging and female sex increase COPD risk.
Lung growth and development – any factor that affects lung growth during gestation and childhood (low birth weight, respiratory infections, etc.) has the potential to increase an individual’s risk of developing COPD.
Socioeconomic status – Poverty is consistently associated with airflow obstruction and lower socioeconomic status is associated with an increased risk of developing COPD. It is not clear, however, whether this pattern reflects exposures to indoor and outdoor air pollutants, crowding, poor nutrition, infections, or other factors related to low socioeconomic status.
Asthma and airway hyper-reactivity – asthma may be a risk factor for the development of airflow limitation and COPD.
Chronic bronchitis – may increase the frequency of total and severe exacerbations.
Infections – a history of severe childhood respiratory infection has been associated with reduced lung function and increased respiratory symptoms in adulthood.
DIAGNOSIS AND ASSESSMENT OF COPD
COPD should be considered in any patient who has dyspnea, chronic cough or sputum production, and/or a history of exposure to risk factors for the disease. Spirometry is required to make the diagnosis in this clinical context the presence of a post-bronchodilator FEV1/FVC < 0.70 confirms the presence of persistent airflow limitation and thus of COPD in patients with appropriate symptoms and significant exposures to noxious stimuli.
Spirometry is the most reproducible and objective measurement of airflow limitation. It is a noninvasive and readily available test. Despite its good sensitivity, peak expiratory flow measurement alone cannot be reliably used as the only diagnostic test because of its weak specificity.
A major differential diagnosis is asthma. In some patients with chronic asthma, a clear distinction from COPD is not possible using current imaging and physiological testing techniques. In these patients, current management is similar to that of asthma. Other potential diagnoses are usually easier to distinguish from COPD
Oximetry and arterial blood gas measurement. Pulse oximetry can be used to evaluate a patient’s arterial oxygen saturation and need for supplemental oxygen therapy. Pulse oximetry should be used to assess all patients with clinical signs suggestive of respiratory failure or right heart failure. If peripheral arterial oxygen saturation is < 92% arterial or capillary blood gases should be assessed
• Smoking cessation is key. Pharmacotherapy and nicotine replacement reliably increase long-term smoking abstinence rates. Legislative smoking bans and counselling, delivered by healthcare professionals improve quit rates.
• The effectiveness and safety of e-cigarettes as a smoking cessation aid is uncertain at present.
• Pharmacological therapy can reduce COPD symptoms, reduce the frequency and severity of exacerbations, and improve health status and exercise tolerance.
• Each pharmacological treatment regimen should be individualized and guided by the severity of symptoms, risk of exacerbations, side-effects, comorbidities, drug availability and cost, and the patient’s response, preference and ability to use various drug delivery devices.
• Inhaler technique needs to be assessed regularly.
• Influenza vaccination decreases the incidence of lower respiratory tract infections.
• Pneumococcal vaccination decreases lower respiratory tract infections.
• Pulmonary rehabilitation improves symptoms, quality of life, and physical and emotional
participation in everyday activities.
• In patients with severe resting chronic hypoxemia, long-term oxygen therapy improves survival.
• In patients with stable COPD and resting or exercise-induced moderate desaturation, long-term
oxygen treatment should not be prescribed routinely. However, individual patient factors must be
considered when evaluating the patient’s need for supplemental oxygen.
• In patients with severe chronic hypercapnia and a history of hospitalization for acute respiratory
failure, long-term non-invasive ventilation may decrease mortality and prevent re-hospitalization.
• In select patients with advanced emphysema refractory to optimized medical care, surgical or
bronchoscopic interventional treatments may be beneficial.
• Palliative approaches are effective in controlling symptoms in advanced COPD.
Smoking cessation has the greatest capacity to influence COPD. If effective resources and time are dedicated to smoking cessation, long-term quit success rates of up to 25% can be achieved. Besides individual approaches to smoking cessation, legislative smoking bans are effective in increasing quit rates and reducing harm from second-hand smoke exposure.
E-cigarettes were originally promoted as a form of nicotine replacement therapy to aid in smoking cessation, although the efficacy to aid smoking cessation remains controversial.64,65 Tetrahydrocannabinol (THC), cannabinoid (CBD) oils, Vitamin E and other flavoring substances and additives have been added to nicotine and promoted to previously non-smoking adolescents and young adults (also known as vaping). Severe acute lung injury, eosinophilic pneumonia, alveolar hemorrhage, respiratory bronchiolitis and other forms of lung abnormalities have been reportedly linked to E-cigarette use.
The U.S. Centers for Disease Control (CDC), the U.S. Food and Drug Administration (FDA), state and other clinical and public health partners are investigating outbreaks of lung illness associated with e-cigarette product use (devices, liquids, refill pods, and/or cartridges)
Oxygen therapy and ventilatory support
Oxygen therapy. The long-term administration of oxygen (> 15 hours per day) to patients with chronic respiratory failure has been shown to increase survival in patients with severe resting hypoxemia.
Breathlessness may be relieved in COPD patients who are either mildly hypoxemic, or non-hypoxemic but do not otherwise qualify for home oxygen therapy, when oxygen is given during exercise training; however, studies have shown no improvement of breathlessness in daily life and no benefit on health-related quality of life.
An exacerbation of chronic obstructive pulmonary disease (COPD) is defined as an acute worsening of respiratory symptoms that result in additional therapy. Exacerbations of COPD are important events in the management of COPD because they negatively impact health status, rates of hospitalization and readmission, and disease progression. COPD exacerbations are complex events usually associated with increased airway inflammation, increased mucus production, and marked gas trapping. These changes contribute to increased dyspnea that is the key. symptom of an exacerbation. Other symptoms include increased sputum purulence and volume, together with increased cough and wheeze.
COPD patients need to receive education about the importance of understanding exacerbation symptoms and when to seek professional healthcare.
COPD exacerbations are mainly triggered by respiratory viral infections although bacterial infections and environmental factors such as pollution and ambient temperature may also initiate and/or amplify these events.