What is chronic obstructive pulmonary disease and how is it treated?
Chronic obstructive pulmonary disease, abbreviated COPD, is a chronic lung disease distinguished by the constant presence of the negative symptoms from the part of the respiratory system and restriction of air flow through the respiratory tract.
The causes of these symptoms are the structural anomalies of the respiratory tract and/or lungs induced by the exposure to harmful particles or gases. In 80% cases, the disease develops as a result of smoking cigarettes.
Short information about chronic obstructive pulmonary disease (COPD)
Other causes of COPD are the contact with dust and aerosols at workplace, exposure to contaminated air as a result of biomass burning inside poorly ventilated rooms.
In around 1% of cases of the disease, the cause is the genetic predisposition and namely deficit of alpha1 antitrypsin.
The damage of the lungs in COPD results from chronic inflammation of the respiratory ways, parenchyma and blood vessels of the lungs, proteolysis (as a result of an imbalance between the activity of proteolytic and antiproteolytic enzymes) and oxidative stress.
What are the symptoms of COPD?
COPD is a progressing disease especially if the patient continues to be exposed to the substances that damage the lungs (especially, tobacco smoke) and can have different manifestations and intensity of manifestations.
Most patients report a history of long-term tobacco smoking. Smoking cessation at every stage of COPD development slows down the rate of loss of lung functional activity. A significant percentage of patients with COPD diagnosed on the basis of the spirometric criterion have no clinical symptoms.
1. Subjective symptoms: chronic coughing occurring periodically or daily, frequently or just for one day, sometimes, only at night; chronic coughing up of sputum especially intensive after waking up; shortness of breath usually daily, first occurring in physical exercise than present even at rest. Unlike asthma, the severity of these symptoms usually varies to a lesser extent throughout the day and from day to day. Patients with severe COPD may complain of fatigue, loss of appetite, weight loss and worsening mood, or other symptoms of depression or anxiety.
2. Objective symptoms: they depend on the stage of the disease (at early stages, they can be absent, especially at rest) and the predomination of bronchitis (wheezing) or emphysema (barrel-shaped chest, decreased respiratory diaphragm mobility, boxed percussion sound, weakened vesicular breathing, prolonged expiration, especially enhanced). In severe COPD, it is especially noticeable how auxiliary breathing muscles participate in inhaling. Exhalation through the closed lips and sometimes bluish color of lips also occur. In case of development of pulmonary heart disease, the symptoms of chronic heart failure occur such as shortness of breath, decreased physical activity, fatigue, swelling, etc.
Patients with low respiratory drive (breathing effort) suffer from less intense shortness of breath and can withstand physical exercising despite hypoxia (low level of oxygen in the blood). Patients with high respiratory drive (intense breathing effort) the balance of gases in the blood is supported by the hyperventilation through the due to significant respiratory effort but they suffer from severe shortness of breath and poor tolerance of physical activity.
3. Exacerbations of the condition are when a sharp worsening of respiratory tract symptoms occurs or if the symptoms day-to-day fluctuation is above the norm and leads to a change in treatment. The main causes for COPD exacerbation are: infections of the airways (usually, viral or bacterial), air pollution, and cessation of the maintenance treatment.
The stages of the disease development are the following:
1. Hypersecretion of sputum, i.e. coughing up of a lot of sputum. However, this symptom occurs not in all patients.
2. Inability to make a deep inhale and exhale that develops due to the obstruction of the mall bronchi and bronchioles.
3. Hyperinflated lungs and emphysema, i.e. the air gets trapped in the lungs as its outflow is restricted by the obstruction.
4. Gas exchange disturbances;
5. The development of pulmonary hypertension (as a result of hypoxic vasoconstriction, structural changes in the wall of the small pulmonary arteries and loss of pulmonary capillaries and pulmonary heart.
6. In lack of adequate therapy and lifestyle changes, total respiratory failure occurs.
Risk factors for COPD
- Tobacco smoking;
- People working in metallurgy, mining and pulp and paper industry, railway workers.
- People over 40 years old.
- People whose relatives had COPD.
What are the possible complications of COPD?
Chronic inflammation, insufficient supply of oxygen to the body tissues, restrained physical activity, and adverse reaction of the used medicines can cause systemic complications - including cachexia (severe weakening of the body), atrophy and impaired skeletal muscle activity, bone deficiency, anemia, and disorders of the central nervous system.
The diseases that accompany COPD including bronchiectatic disease, arterial hypertension, coronary heart disease, heart rhythm disturbances, stroke, diabetes mellitus and anxiety-depressive disorders, influence the general condition and worsen the treatment prognosis. In their presence, the risk of lung cancer is increased.
Diagnosis of COPD
The typical symptoms of the disease along with the risk factors (i.e. tobacco smoking, professional risk, etc.) can make a physician suspect COPD. To confirm the diagnosis, the following tests are made:
- Complete blood count (without white blood cell count and ESR). In COPD, changes in the general blood count are usually absent. In exacerbation, polycythemia, an increase in the level of red blood cells, hemoglobin, and hematocrit can be observed. In addition, this analysis is also used to exclude the infectious nature of the symptoms.
- General analysis of sputum. In COPD, sputum is usually viscous and colorless. The test is necessary to exclude a number of lung diseases: cancer, tuberculosis, pneumonia, etc.
- Arterial blood gas analysis. It is necessary to determine how well is blood saturated with oxygen and carbon dioxide, as well as to evaluate the acid-base state, which is an indicator of lung function. In COPD, oxygen levels decrease, and carbon dioxide levels increase while the pH of the blood lowers.
Functional tests include:
- Spirometry: In this study, the patient takes a deep breath, and then quickly exhales into a special device - a spirometer. It is used to measure expiratory air volume and expiratory flow. In COPD, these indicators can be reduced even before other symptoms occur.
- Bronchodilation test: the patient takes the drug that dilates bronchi, preferably, short-acting bronchodilator inhaler. The test is necessary for the differential diagnosis of COPD and asthma, which is also manifested by obstruction of the airways. In bronchial asthma under the influence of bronchodilators, bronchial patency is fully restored, with COPD no (due to severe structural disorders in the lung tissue).
- Plethysmography tests an increase in the residual volume and functional residual capacity, and the ratio of the residual volume to the total lung capacity in case of pulmonary hyper air or emphysema;
- The study of the diffusion ability of gases in the lungs (useful in patients with shortness of breath, which seems to be disproportionate to the degree of airway obstruction).
- Assessment of exercise tolerance, which is reduced in the late stages of the disease and correlates with general health status and prognosis:
a) Marching tests (6-minute walk test, step or endurance shuttle test with an increasing pace of walk);
b) A cardiopulmonary exercise test using a treadmill or cycloergometer;
c) Monitoring activity using accelerometers or other devices.
Other diagnostic methods:
- Chest x-ray and computed tomography (CT) shows the reduction and flattening of the domes of the diaphragm, an increase in the anteroposterior size of the chest, transparency of the lungs and retrosternal air space; in case of pulmonary hypertension, a decrease or absence of vascular pattern on the periphery of the lungs, expansion of the pulmonary arteries, an increase in the right ventricle. CT is allows to diagnose the type of emphysema, identify the exacerbation and localization of emphysema changes, as well as detect concomitant bronchiectasis.
- Bronchoscopy is an examination of the mucous membrane for deformities. To do this, a special device, a bronchoscope is used. It consists of a flexible rod equipped with a video camera, a backlight and a manipulator for taking a sample of bronchial tissue.
- Pulse oximetry helps to diagnose the level of oxygen in the blood through the skin.
- ECG and echocardiography are used to exclude the manifestations of pulmonary heart disease.
- Assessment of alpha1-antitrypsin deficiency in patients aged <45 years (especially non-smokers) or with a family history of the disease.
Interpretation of COPD diagnosis
1) The degree of obstruction based on the spirometry:
- ≥80 % mild;
- ≥50 % (<80 %) moderate;
- ≥30 % (<50 %) severe;
- <30 % extremely severe.
2) The nature and severity of subjective symptoms, as well as the risk of exacerbations:
- The intensification of the subjective symptoms is assessed using CAT or CCQ tests (the result >1–1,5 indicates high intensity of symptoms). mMRC scale can be used for the assessment of severity of shortness of breath (the result ≥2 indicates high intensity). The tests can be found on the Internet and done by a patient at home.
- The risk of complications is assessed based on the number of exacerbations during the last 12 months (<2 – low risk, ≥2 – high risk); hospitalization due to COPD in the last 12 months (just one hospitalization already indicates high risk).
3) Presence of other health conditions.
Differential diagnosis of COPD
Differential diagnosis means the exclusion of other diseases that manifest similarly to COPD. First of all, it is asthma.
Asthma usually starts in childhood. The symptoms have a variable severity character, often they develop at night and in the morning. Functional tests indicate a variable and often reversible restriction of air flow in the airways. In some patients, it can be difficult to distinguish asthma from COPD, and some patients have symptoms of both diseases, respectively, they are diagnosed with a cross between asthma and COPD.
Differences between asthma and COPD
- The severity of symptoms may change within minutes, hours or days.
- Symptoms intensify at night or early in the morning.
- Symptoms are triggered by physical exertion, emotions (including laughter), exposure to dust or allergens.
- Symptoms persist despite treatment;
- There are “good” and “bad” days, but symptoms occur daily, shortness of breath in physical activity is permanent;
- Chronic cough and sputum discharge precede the occurrence of shortness of breath, symptoms do not depend on provoking factors.
- Preliminary/previous diagnosis of COPD, chronic bronchitis or emphysema;
- Significant impact of risk factors: smoking or use of organic substances.
- Symptoms do not worsen over time; the severity of the symptoms changes seasonally or in the following years;
- Spontaneous improvement is possible either with the use of a bronchodilator (immediately) or glucocorticoids (within a few weeks).
- Symptoms progress slowly over time (disease lasts for years).
- The use of a quick-acting bronchodilator brings only partial improvement.
How to use the table: the table shows the differences between bronchial asthma and COPD. It is important to calculate the characteristic features for a given patient and compare them. If there are ≥3 features for asthma or COPD found in a certain patient, then he or she likely has the disease corresponding to the features.
Other diseases that should be excluded are:
1) Bronchiectasis, characterized by profuse purulent sputum, with listening of the chest, wheezing over the pulmonary fields is heard. R-ray and CT show the expansion of the bronchi and thickening of the bronchial wall;
2) Left ventricular heart failure – when listening to the lungs, crepitus (clicks that occur only at the end of inspiration - the beginning of exhalation) at the base of the lungs is heard. X-ray shows the expansion of the shadow of the heart and signs of stagnation in the pulmonary circulation.
3) Tuberculosis – wheezing is rare, usually, the typical changes are seen on the x-ray.
4) Lung cancer is characterized with quick development of symptoms, changes in the type of chronic coughing, body mass lose, lung bleeding.
5) Bronchiolitis obliterans, a tumor or a foreign body in the airways, pulmonary hypertension, tracheobronchomalacia, infections of the lower respiratory tract.
6) Other reasons of chronic coughing – commonly, cardiovascular diseases.
Treatment of COPD
1. Complete cessation of tobacco smoking and avoiding passive smoking.
2. Physical exercising (recommended for any stage of COPD);
3. Rehabilitation: all patients (with the exception of patients with mild severity of symptoms and a low risk of exacerbations), especially those who, despite the optimal treatment, have shortness of breath, and a decrease in exercise tolerance limits daily life. The most effective are lasting ≥6 weeks (the longer, the stronger the effects), comprehensive programs that include breathing exercises, general strengthening physical exercises, education of the patient and their relatives, tobacco dependence treatment, psychological support and psychosocial interventions, nutritional counseling and diet therapy.
Education of patients (it must be combined with methods of controlled patient participation in treatment): depending on the severity of COPD, training should include the following:
1) For all patients: the essence of the disease and its course, as well as treatment options, reduced contact with risk factors, the role of physical activity, proper nutrition, and sufficient sleep;
2) For patients with very severe symptoms: methods of dealing with shortness of breath, methods of saving energy in the process of daily life, methods of dealing with stress;
3) For patients with a high risk of exacerbations: avoidance of factors that aggravate symptoms, monitoring of symptoms and tactics of action in case of their intensification, a written action plan and its importance;
4) For patients with a high severity of symptoms and a high risk of exacerbations: palliative treatment, questions regarding the completion of a life course, information that simplifies decision making ahead of tactics in the terminal phase of the disease.
5) Adequate nutrition: Diet therapy includes the intake of the required number of calories, for example, frequent small meals throughout the day. If necessary, dietary supplements can be added to the diet. Look for factors that may interfere with eating (e.g. shortness of breath, poor teeth, or cooking problems). In obese patients, weight loss methods should be considered.
6) Vaccination against influenza (for all patients) and vaccination against pneumococcal infection (for patients aged ≥65 years), and for younger patients with serious concomitant diseases, for example, cardiac pathology.
7) The treatment of patients with concomitant bronchiectasis is no different from the treatment of other patients with COPD, but during exacerbations, more intensive and longer antibiotic therapy may be required.
8) Patients with a terminal phase of very severe COPD should be given palliative care aimed at improving the quality of life and daily functioning.
Drug treatment of COPD
The drug therapy is aimed at the lowering of symptoms manifestation and improvement of quality of life. It includes:
- Bronchodilators – these are drugs that relax the smooth muscles of the bronchi, which leads to the expansion of their lumen and easier breathing. They are usually used in the form of inhalers, that is, by inhalation of steam or smoke containing a medicinal substance. They can be used depending on the severity of the disease both periodically and constantly. For acute suffocation attacks and shortness of breath, quick-acting bronchodilators such as Proventil (Albuterol) are used. Long-acting bronchodilators can be also used for the prophylaxis of bronchospasms but they have lower effectiveness than in asthma.
- Inhaled glucocorticosteroids. These medicines are used to reduce inflammation and the rate of disease progression. They are usually used in courses in patients with terminal stages of the disease or during severe exacerbation of COPD.
- Antibiotics. The antibiotics are used for bacterial complications that are often found in patients with COPD.
Keep in mind that different inhalers are used differently. When you get your first inhaler or replace one device with another, you need to get instructed by a doctor or nurse on how to use it properly as it greatly affects the effectiveness of therapy.
Surgical treatment of COPD
- Lung transplant. It is used in severe cases. It improves the quality of life, but does not increase live expectancy.
- Surgery to reduce lung volume. This is the removal of damaged sections of the lung, which frees up additional space in the chest cavity, which helps to facilitate lung function. The possible consequences of this method, unfortunately, have not been sufficiently studied.
Post by: Natalie Keller, M.D. Lung Health Centre, Minneapolis, Minnesota