What is COPD
There COPD, also called chronic obstructive pulmonary disease or, in English, COPD (Chronic obstructive pulmonary disease), is a chronic and progressive disease that affects the lungs. It occurs more frequently in smokers over 40 years of age.
It is common to wonder what the precise meaning of this name is: COPD, in fact, often causes confusion, since it refers to a heterogeneous clinical picture and not to a specific pulmonary alteration, so it is good to start with a definition.
Definition of COPD: “Common disease characterized by persistent restriction of airflow, usually progressive and associated with an increase in chronic inflammation. The exacerbations and comorbidities contribute to the severity of the patients as a consequence of the inhalation of particles and gases. "
Let's clarify further: the acronym COPD does not indicate a specific disease with defined characteristics, but a syndrome (in which flow limitation and inflammation are included) attributable to two different pathological pictures:
- Obstructive bronchiolitis: it is an alteration in the small respiratory tract caused by chronic inflammation.
- Pulmonary emphysema: emphysema is an alteration of the lung parenchyma (the portion of the organ responsible for gas exchange).
The airways, in fact, are real air ducts that end in alveoli, spherical elements closely connected to the elastic structures of the lung. They are separated by interalveolar septa; they are also in close contact with the pulmonary capillaries and this allows oxygenation of the blood during breathing. In emphysema the septa are damaged until they disappear, the exchange surface for oxygenation is reduced and moreover the air remains "trapped" in these emphysematous dilations, creating an obstacle to normal breathing.
The consequence of these alterations is a bronchial obstruction irreversible and, consequently, the persistent reduction in airflow characteristic of COPD. This flow is mainly regulated by two factors:
- Alveolar pressure: the distension and the release of the lung parenchyma with the respiratory acts determine variations in volume and especially in pressure; the latter has a direct impact on pulmonary alveoli, thus affecting the flow. Emphysema, destroying the walls of the alveoli and elastic structures, thus contributes to the reduction of flow.
- Airway caliber: an obstruction, as well as a thickening of the wall that simply reduces the diameter of the bronchi, obstructs the flow contributing to the onset of obstructive dysfunctions. In the specific case of COPD, the caliber of the bronchi is altered due to the obstructive bronchiolitis (more precisely, it is a situation of bronchostenosis, in which the resistance to flow is increased due to a reduced diameter).
Causes of COPD
The origin of COPD can be attributed to several factors:
- Exposure to harmful agents: inhalation of cigarette smoke (active and passive), environmental pollutants and occupational exposure to some agents are an important damaging stimulus on the respiratory system, especially in subjects already susceptible due to other factors, therefore they determine the alterations affecting the bronchi. In particular, smoking is one of the main causes of onset (20% of smokers develop a picture of COPD).
- Genetic factors: some genetically transmitted diseases (such as alpha-antitrypsin deficiency) can predispose to COPD; moreover, it occurs more frequently in relatives of already affected subjects. In genetically predisposed individuals, smoking is a trigger important.
COPD goes through several stages:
- Hypersecretion of mucus: it causes a productive cough, that is rich in sputum, and chronic, therefore very annoying.
- Chronic obstructive bronchitis: the inflammatory picture will be important especially in exacerbations (or "exacerbations" of the disease);
- Emphysema: the production of lytic enzymes by the cells involved in inflammation, as already mentioned, destroys the septa, forming typical dilations. This is hyperinflation or pulmonary hyperinflation: the inhaled air will remain “trapped” in the lung and the patient will find it more difficult to expel it. The chest will take on a particular conformation, which mimics a constant inspiratory act, said barrel chest.
The onset of COPD in many cases is asymptomatic: when the patient goes to the doctor because of the symptoms, the structural damage to the lung has already been present for some time.
The initial symptoms of COPD are:
- Dyspnea: or the unpleasant awareness of one's breath. It begins as a feeling of shortness of breath after a certain effort and, in the advanced stages, hinders normal daily activities. The extent of dyspnea is assessed with the MRC scale, a questionnaire in which the patient reports the level of effort with which he begins to feel dyspnea. The score ranges from 1 (only with intense efforts) to 5 (dyspnea is so important that it prevents him from daily activities, even from leaving the house).
- Cough chronic and productive;
If symptoms are present for more than 3 months of the year for a period of at least 2 years we speak of chronic bronchopathy.
Chronic bronchitis, due to the persistence of the inflammatory state, causes a real "remodeling" of the airways, which thicken and, as already mentioned, reduce their caliber. This alteration is permanent, unlike what happens in the acute bronchitis: in this case, the flow is obstructed because the airways are "edematous" and a lot of mucus is produced. In the case of asthmatic bronchitis, bronchial hyperreactivity is added to the acute picture just described, which exacerbates the symptoms even more (all this is however more frequent in children).
At the clinical examination, the patient will also present:
- Barrel chest, consequence of pulmonary hyperinflation;
- Wheezing, especially in the exhale you hate exhalation, when air is expelled from the lungs through the mouth or nose.
- Reduced inspiratory noises;
- Swelling of the legs (edema) e protrusion of the vessels of the neck (jugular turgor): these signs are a consequence of the increase in pressure in the pulmonary circulation that occurs in advanced states of the disease. This pressure overload condition, with origin in the pulmonary vessels and repercussions on the right heart, is called chronic pulmonary heart.
We also distinguish two typical symptom pictures:
- Pink Puffer: the patient is cachectic (ie very thin), dyspnoic, has a rosy complexion and typically breathes with a narrow mouth (an unconscious way in which he tries to improve breathing). He suffers from emphysematous COPD: often there is a considerable loss of muscle mass in the legs because the respiratory acts, due to the hyperinflation of the lungs, require a greater expenditure of energy that the body derives from muscle demolition.
- Blue Bloater: the patient typically has bronchitis chronic. It has a more florid (defined plethoric), is rich in secretions and has swollen ankles.
In COPD, especially in the advanced stages, are frequent exacerbationsSymptoms worsen dramatically and rapidly, usually due to viral or bacterial pneumonia. Other causes can be environmental pollution, secondhand smoke, misuse of drugs or pulmonary embolism.
It is also possible to come across a mixed picture of COPD and asthma (we speak of COPD asthmatiform). Asthma, like COPD, is also an obstructive pathology of the bronchi, in which, however, bronchoconstriction is acute and reversible. In a mixed picture, the COPD patient presents all the characteristics and symptoms listed above (smoker, over 40 years of age, dyspnoea ...), however episodes of acute bronchoconstriction responsive to bronchodilators may occur, usually ineffective in the presence of chronic obstructive pulmonary disease.
Complications of COPD
A condition such as COPD makes the lung more vulnerable to secondary diseases.
- People with COPD are more susceptible to respiratory infections which, as already mentioned, also cause exacerbations.
- Another risk they are exposed to is that cardiovascular (heart attack, arterial hypertension) for causes not yet fully understood.
- The smoking and chronic bronchitis also increase the risk of developing a lung cancer.
- COPD in more advanced stages drastically compromises the quality of life; due to this the patients can also develop depression.
The clinical suspicion of COPD concerns all subjects over the age of 35-40 who present to the doctor's attention with dyspnea, chronic cough and sputum; particularly if smokers or exposed to other risk factors. However, diagnostic confirmation will only be obtained with instrumental investigations.
The gold standard for the diagnosis of COPD is the spirometry, a test that allows to detect flows and changes in lung volume in the various phases of respiration. Indeed, these respiratory function parameters will typically be altered in COPD. In particular, you will have:
- Tiffeneau index, or relationship between FEV1 / CVF less than 70%.
- The FEV1 or VEMS it is the maximum volume that the patient is able to exhale, in the first second, with a forced exhalation.
- There CVF (forced vital capacity) is the maximum volume that can be expelled with a forced exhalation, after having performed a maximal inhalation.
It is important to do differential diagnosis with bronchial asthma, that the spirometric test is performed after the administration of a bronchodilator (eg. salbutamol): in asthma, in fact, bronchospasm causes a reversible obstruction with the administration of the drug; the bronchospasm of COPD instead is a non-reversible bronchospasm, therefore the respiratory function does not improve with the inhalation of the bronchodilator.
Spirometry allows you to classify the disease using the GOLD criteria:
- mild: VEMS> 80%.
- moderate: VEMS between 50% and 80%.
- serious: VEMS between 30% and 50%.
- very serious: VEMS <30%.
Spirometry is also a fundamental test from a medico-legal point of view, since the attribution of civil invalidity and exemptions for COPD sufferers is based on diagnostic evidence obtained with spirometry testing.
Other tests that support the diagnosis are:
- X-ray: shows an upward concave diaphragm (the classic domed appearance is reversed due to the expansion of the emphysematous lungs), cardiac hypertrophy and other signs correlated with emphysema.
- Laboratory: blood test
- Increase in inflammatory indices (High CRP, High ESR, etc.), especially in exacerbations;
- Polycythemia (increase in the number of red blood cells), induced by the chronic reduction of oxygen levels;
- Sputum examination to check for bacteria in case of suspected lung infection;
- Alpha-antitrypsin dosage (alpha-antitrypsin deficiency could be a predisposing factor);
- Blood gas analysis: Due to COPD, blood oxygenation is no longer efficient, so there will be reduced levels of oxygen and increased levels of carbon dioxide in the blood.
- 6-minute stress test: the patient is placed under physical effort and, during the test, saturation (i.e. the percentage of oxygen linked to hemoglobin) is monitored; an abrupt reduction in saturation indicates a reduced tolerability to exercise and a deficit in normal breathing.
COPD is a chronic disease for which there is still no definitive therapy, therefore the treatment aims to reduce the symptoms and above all to delay the progression of the disease.
A first step in reducing COPD-associated mortality is definitely stop smoking. A good helper is thehome oxygen therapy as it improves blood oxygenation and reduces respiratory work. Certain physiotherapy exercises can help improve the efficiency of the respiratory muscles.
The guidelines for the pharmacological therapyInstead, they vary according to the symptoms and frequency of exacerbations, or the stage of COPD. In fact, we can distinguish:
- Group A: few symptoms and few exacerbations; for this class the administration of bronchodilators, not necessarily long-lasting.
- Group B: more symptoms and fewer exacerbations. For these patients they are recommended anticholinergics (LAMA) is long-lasting bronchodilators (LABA). Both have the goal of increasing the caliber of the airways, thus promoting breathing.
- Group C: few symptoms and frequent exacerbations. Treated with LAMA or LAMA + LABA. The latter can also associate with one steroid inhalation.
- Group D: severe symptoms and frequent exacerbations. One is used for these patients dual therapy (LAMA + LABA), which can also be triple if they are associated steroids.
The lung transplant is a therapeutic option for advanced COPD cases in selected patients.
COPD treatment exacerbated
For exacerbations, treatment aims to prevent new episodes. This is done by administering:
- Corticosteroids intravenous;
- Antibiotics in case of positive sputum due to bacterial infection;
- Oxygen therapy;
- NIV: non-invasive CPAP ventilation (with a Boussignac mask or a Venturi mask) helps the patient to ventilate without having to resort to orotracheal intubation.
- In case of respiratory failure and acidosis, intubation with assisted ventilation.