Chronic obstructive pulmonary disease, also known as COPD, is a chronic, progressive disease that limits the flow of air through the lungs.
Chronic obstructive pulmonary disease
- It is a comprehensive term that includes two conditions; of chronic bronchitis , and emphysema. Where chronic inflammation damages the lungs, obstructing the flow of air.
- It is an autosomal dominant disorder; Alpha-1 deficiency, called antitrypsin, leads to the breakdown of lung parenchyma by an enzyme called elastase copd, characterized by long-term inflammation of T.
- The bronchial tubes are referred to as chronic bronchitis, and the alveolar destruction is referred to as emphysema.
- Before we look at the pathogenesis of COPD, let’s move on to some basic anatomy and physiology of the lung.
Alveoli and Bronchioles
- Alveoli are the functional aspects of the lung, it is the tissue responsible for the gaseous exchange of oxygen and carbon dioxide.
- In order for air to exchange between the atmosphere and the alveoli, it must first travel through a network of tubes within the lungs known as the large and small airways; Which consists of the main airways.
- Bronchioles, and Tertiary Bronchioles These bronchi do not participate in the diffusion of gases, but provide the alveoli with access to the external environment.
chronic obstructive pulmonary disease causes
- Chronic bronchitis is essentially a symptom of a productive cough on a chronic basis, while emphysema is more caused by the destruction of the lung parenchyma.
- And what that can do over time is that it can cause the lung to over-inflate, and that’s due to air being trapped inside.
- So keep these two components in mind in terms of etiology, the most common reason a person develops COPD is due to smoking.
- Smoking is responsible for about 95 percent of cases, as the toxins in smoke cause chronic immune responses, which cause irreversible damage.
- Another cause is air pollutants, pollutants and strong chemicals, usually from inhalation of toxic substances such as occupational pollutants such as dust, and silica.
- The most rare cause is a genetic condition called alpha-1 antitrypsin deficiency which is an autosomal dominant genetic disease, usually affecting people before the age of 40, and there is a family history of alpha-1 antitrypsin disease.
- The alpha 1 antitrypsin is a protease inhibitor, which is synthesized by the liver and helps to regulate protease activity. Proteases break down proteins and inhibit alpha-1 antitrypsin proteases.
chronic bronchitis causes
Let’s start by looking at the pathogenesis of chronic bronchitis :
- Continuous airway exposure leads; to irritants such as tobacco, to persistent inflammation, and the recruitment of immune cells from the mucous glands. and goblet cells that lead to excessive secretion of mucus, in an attempt to protect the airways from pathogens.
- Constant exposure to irritants and excessive secretion of mucus cause ciliary dysfunction. Cilia become damaged and become less mobile, which means that they struggle to remove mucus and pathogens from the airways.
- Excessive mucus leads to the formation of a plug, impeding air flow.
- Failure to remove pathogens due to weakened pulmonary defense mechanisms leads to further infection, and inflammation resulting in a worsening of the condition.
- Thick mucus narrows the airways, forming a mucus plug.
- Because inhalation is an active process that uses the muscles of breathing, this partial obstruction of the airway can be overcome, although the amount of air entering can be reduced.
- However, the difficulty occurs during exhalation because this is a passive process, as the respiratory muscles work to relax the pressure of the outgoing air.
- Which struggles to overcome the narrow air passages, which leads to air retention in the alveoli in particular, and results in reduced carbon dioxide removal.
- We know that oxygen and carbon dioxide will move down their concentration gradients from areas of high amounts to areas of low amounts.
- The carbon dioxide in the alveoli is usually low partial pressure, which means it is less than the amount found in the blood.
- This allows carbon dioxide to easily pass from the blood into the alveoli where it is exhaled, as it travels from an area of high pressure in the blood, to an area of low pressure in the alveoli.
- Conversely, oxygen has a high partial pressure in the alveoli, which means that there is more of it. This causes it to diffuse easily through the alveoli into the blood, where it moves from an area of high concentration to an area of low concentration.
- Based on the above, the amount of carbon dioxide increases inside the alveoli, where it becomes trapped. Which means that it is difficult for carbon dioxide to leave the blood, and enter the alveoli, due to the difference in pressure.
- Dioxide is reduced between the alveoli and the blood, and likewise the amount of oxygen inside the alveoli is reduced making it difficult for the oxygen to move into the swell.
- Where it produces a difference between the oxygen levels of the alveoli, and the oxygen levels in the blood, which leads to low levels of oxygen in the blood known as hypoxia.
- As well as increased levels of carbon dioxide in the blood, known as hypercapnia.
Considering the changes that occur in emphysema
- Gas exchange in a healthy person, which mainly affects the functional units of the lungs, which are the alveoli covered with elastic fibers, allows the alveoli to expand and retract, which pushes the air out during exhalation.
- But in emphysema there is a loss of elastic fibers, and also a decrease in the surface area of the alveoli, which can lead to the collapse of the alveoli.
- This results in something called air trapping, where air is still trapped in the alveoli during exhalation.
- Because the recoil mechanism is not working properly, ‘losing rebound elasticity’, and we have problems along the airway and specifically the bronchioles.
chronic obstructive pulmonary disease symptoms
- Most people with COPD have components of chronic bronchitis and emphysema, which leads to excessive secretion of mucus by respiratory goblet cells and mucus.
- A plug forms that blocks the airways, causing air retention, and it also causes chronic obstruction of the cough produced in the bronchi.
- They can also cause shortness of breath that can progress to shortness of breath, fatigue, wheezing and chest tightness, destruction of alveolar sacs, impairing gas exchange resulting in hypoxia, and hypercapnia.
- Loss of elastic rebound causes the airways to collapse during exhalation, trapping air, and expanding air spaces to facilitate breathing.
- Where patients with chronic pneumonia often use the tripod position, where they sit and lean forward and put their hands on their knees, they can use mouth breathing to prolong the exhalation.
- They produce positive expiratory pressure or peeps that allow them to exhale as much air as possible, and because this breathing technique requires the use of accessory breathing muscles.
- Thus you will spend a lot of energy; Just breathing in the trapped air also increases the anteroposterior diameter of the chest sometimes called the barrel.
- Chronic hypoxemia in the chest can lead to cyanosis, and the lips or fingertips can turn blue.
- It also causes constriction of the pulmonary vessels and pulmonary hypertension, which increases the workload on the right side of the heart, leading to right-sided heart failure.
chronic obstructive pulmonary disease diagnosis
- Based on the patient’s history, physical examination and pulmonary function tests or PFTs are required to assess the degree of airway restriction, and to diagnose chronic pneumonia.
- Forced expiratory volume in one second, or FEV1 and vital capacity, or FVC, are measured after the patient is given a bronchodilator such as albuterol a FEV1.
- An FVC score of less than 70 percent indicates airway obstruction, because COPD is an irreversible disease, and therefore a bronchodilator does not change a person’s symptoms much.
- Finally, screening for alpha-1 anti-trypsin deficiency may also be performed, and given to reduce the risk of respiratory infection.
chronic obstructive pulmonary disease treatment
- Although COPD is an irreversible disease; Bronchodilators can help relieve symptoms.
- Steroids can reduce inflammation in the lungs, and supplemental oxygen may be needed to maintain oxygen saturation between 88 to 92 percent for these patients.
- The aim of giving additional oxygen is not only saturation with oxygen, but also hypoxia of the blood being the main trigger of their respiratory drive.
- Finally because these individuals expend so much of their energy on simply breathing, dietary modifications may be required to maintain weight, and muscle mass.
- To summarize, COPD is a progressive disease, which limits the flow of air through the lungs and is irreversible. It is basically a problem with exhalation, not inhalation.
- There are two cases of chronic bronchitis and emphysema, and the reason these conditions are called COPD is that they co-exist naturally.
- The patient suffers from one disease more prevalent than chronic bronchitis, which is the excessive secretion of mucus due to chronic inflammation that causes the patient to have symptoms.
- While emphysema causes structural changes in the alveoli and small airways, an exacerbation is an acute exacerbation of a patient’s symptoms.
- We are committed to raising COPD awareness, so that people who are at risk or who are in the early stages of COPD can get help early and get back to doing the things they love.
- Chronic pneumonia can affect quality of life, causing people to be unable to carry out daily tasks and to stop socializing.
- COPD is highly treatable, when symptoms are properly managed. It can be greatly relieved and people with COPD can enjoy a better quality of life.
- That’s why it’s important to recognize the signs and symptoms so that we can recognize them early and talk to a healthcare professional to find ways to manage them.