30 Jan Chronic Obstructive Pulmonary Disease
Chronic Obstructive Pulmonary Disease
Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory lung disease that causes obstructed airflow from the lungs. Symptoms include breathing difficulty, cough, mucus (sputum) production and wheezing. It’s typically caused by long-term exposure to irritating gases or particulate matter, most often from cigarette smoke. People with COPD are at increased risk of developing heart disease, lung cancer and a variety of other conditions.
Emphysema and chronic bronchitis are the two most common conditions that contribute to COPD. These two conditions usually occur together and can vary in severity among individuals with COPD.
Chronic bronchitis is inflammation of the lining of the bronchial tubes, which carry air to and from the air sacs (alveoli) of the lungs. It’s characterized by daily cough and mucus (sputum) production.
Emphysema is a condition in which the alveoli at the end of the smallest air passages (bronchioles) of the lungs are destroyed as a result of damaging exposure to cigarette smoke and other irritating gases and particulate matter.
Although COPD is a progressive disease that gets worse over time, COPD is treatable. With proper management, most people with COPD can achieve good symptom control and quality of life, as well as reduced risk of other associated conditions.
Lung Diseases Affecting the Airways
Your windpipe (trachea) branches into tubes called bronchi, which in turn become smaller tubes throughout your lungs. Diseases that can affect these airways include:
- Asthma. Your airways are constantly inflamed and may spasm, causing wheezing and shortness of breath. Allergies, infections, or pollution can trigger asthma symptoms.
- Chronic obstructive pulmonary disease (COPD). With this lung condition, you can’t exhale the way you usually would, which causes trouble breathing.
- Chronic bronchitis. This form of COPD brings a long-term wet cough.
- Emphysema. Lung damage allows air to be trapped in your lungs in this form of COPD. Trouble blowing air out is its hallmark.
- Acute bronchitis. This sudden infection of your airways is usually caused by a virus.
- Cystic fibrosis. With this condition, you have trouble clearing mucus out of your bronchi. This leads to repeated lung infections.
Lung Diseases Affecting the Air Sacs (Alveoli)
Your airways branch into tiny tubes (bronchioles) that end in clusters of air sacs called alveoli. These air sacs make up most of your lung tissue. Lung diseases affecting your alveoli include:
- Pneumonia. An infection of your alveoli, usually by bacteria or viruses, including the coronavirus that causes COVID-19.
- Tuberculosis Pneumonia that slowly gets worse, caused by the bacteria Mycobacterium tuberculosis.
- Emphysema. This happens when the fragile links between alveoli are damaged. Smoking is the usual cause. (Emphysema also limits airflow, affecting your airways.)
- Pulmonary edema. Fluid leaks out of the small blood vessels of your lung into the air sacs and the area around them. One form is caused by heart failure and back pressure in your lungs’ blood vessels. In another form, injury to your lung causes the leak of fluid.
- Lung cancer. It has many forms and may start in any part of your lungs. It most often happens in the main part of your lung, in or near the air sacs.
- Acute respiratory distress syndrome (ARDS). This is a severe, sudden injury to the lungs from a serious illness. COVID-19 is one example. Many people who have ARDS need help breathing from a machine called a ventilator until their lungs recover.
- Pneumoconiosis. This is a category of conditions caused by inhaling something that injures your lungs. Examples include black lung disease from coal dust and asbestosis from asbestos dust.
COPD symptoms often don’t appear until significant lung damage has occurred, and they usually worsen over time, particularly if smoking exposure continues.
Signs and symptoms of COPD may include:
- Shortness of breath, especially during physical activities
- Chest tightness
- A chronic cough that may produce mucus (sputum) that may be clear, white, yellow or greenish
- Frequent respiratory infections
- Lack of energy
- Unintended weight loss (in later stages)
- Swelling in ankles, feet or legs
People with COPD are also likely to experience episodes called exacerbations, during which their symptoms become worse than the usual day-to-day variation and persist for at least several days.
When to see a doctor
Seek immediate medical care if you can’t catch your breath, if you experience severe blueness of your lips or fingernail beds (cyanosis) or a rapid heartbeat, or if you feel foggy and have trouble concentrating.
The main cause of COPD in developed countries is tobacco smoking. In the developing world, COPD often occurs in people exposed to fumes from burning fuel for cooking and heating in poorly ventilated homes.
Only some chronic smokers develop clinically apparent COPD, although many smokers with long smoking histories may develop reduced lung function. Some smokers develop less common lung conditions. They may be misdiagnosed as having COPD until a more thorough evaluation is performed.
How your lungs are affected
Air travels down your windpipe (trachea) and into your lungs through two large tubes (bronchi). Inside your lungs, these tubes divide many times — like the branches of a tree — into many smaller tubes (bronchioles) that end in clusters of tiny air sacs (alveoli).
The air sacs have very thin walls full of tiny blood vessels (capillaries). The oxygen in the air you inhale passes into these blood vessels and enters your bloodstream. At the same time, carbon dioxide — a gas that is a waste product of metabolism — is exhaled.
Your lungs rely on the natural elasticity of the bronchial tubes and air sacs to force air out of your body. COPD causes them to lose their elasticity and over-expand, which leaves some air trapped in your lungs when you exhale.
Lung Diseases Affecting the Interstitium
The interstitium is the thin, delicate lining between your alveoli. Tiny blood vessels run through the interstitium and let gas transfer between the alveoli and your blood. Various lung diseases affect the interstitium:
- Interstitial lung disease (ILD). This is a group of lung conditions that includes sarcoidosis, idiopathic pulmonary fibrosis, and autoimmune disease.
- Pneumonia and pulmonary edema can also affect your interstitium.
Lung Diseases Affecting Blood Vessels
The right side of your heart gets low-oxygen blood from your veins. It pumps blood into your lungs through the pulmonary arteries. These blood vessels can have diseases, as well.
- Pulmonary embolism (PE). A blood clot (usually in a deep leg vein, called deep vein thrombosis) breaks off, travels to your heart, and gets pumped into your lungs. The clot sticks in a pulmonary artery, often causing shortness of breath and low blood oxygen levels.
- Pulmonary hypertension. Many conditions can cause high blood pressure in your pulmonary arteries. This can lead to shortness of breath and chest pain. If your doctor can’t find a cause, they’ll call it idiopathic pulmonary arterial hypertension.
Lung Diseases Affecting the Pleura
The pleura is the thin lining that surrounds your lung and lines the inside of your chest wall. A tiny layer of fluid lets the pleura on your lung’s surface slide along the chest wall with each breath. Lung diseases of the pleura include:
- Pleural effusion. Fluid collects in the space between your lung and the chest wall. Pneumonia or heart failure usually causes this. Large pleural effusions can make it hard to breathe and may need to be drained.
- Pneumothorax. Air may get into the space between your chest wall and the lung, collapsing the lung.
- Mesothelioma. This is a rare form of cancer that forms on the pleura. Mesothelioma tends to happen several decades after you come into contact with asbestos.
Lung Diseases Affecting the Chest Wall
Your chest wall also plays an important role in breathing. Muscles connect your ribs to each other, helping your chest expand. Your diaphragm descends with each breath, also causing chest expansion. Diseases that affect your chest wall include:
- Obesity hypoventilation syndrome. Extra weight on your chest and belly can make it hard for your chest to expand. This may cause serious breathing problems.
- Neuromuscular disorders. You might have trouble breathing when the nerves that control your respiratory muscles don’t work the way they should. Amyotrophic lateral sclerosis and myasthenia gravis are examples of neuromuscular lung disease.
Causes of airway obstruction
Causes of airway obstruction include:
- This lung disease causes destruction of the fragile walls and elastic fibers of the alveoli. Small airways collapse when you exhale, impairing airflow out of your lungs.
- Chronic bronchitis.In this condition, your bronchial tubes become inflamed and narrowed and your lungs produce more mucus, which can further block the narrowed tubes. You develop a chronic cough trying to clear your airways.
Cigarette smoke and other irritants
In the vast majority of people with COPD, the lung damage that leads to COPD is caused by long-term cigarette smoking. But there are likely other factors at play in the development of COPD, such as a genetic susceptibility to the disease, because not all smokers develop COPD.
Other irritants can cause COPD, including cigar smoke, secondhand smoke, pipe smoke, air pollution, and workplace exposure to dust, smoke or fumes.
In about 1% of people with COPD, the disease results from a genetic disorder that causes low levels of a protein called alpha-1-antitrypsin (AAt). AAt is made in the liver and secreted into the bloodstream to help protect the lungs. Alpha-1-antitrypsin deficiency can cause liver disease, lung disease or both.
For adults with COPD related to AAt deficiency, treatment options include those used for people with more-common types of COPD. In addition, some people can be treated by replacing the missing AAt protein, which may prevent further damage to the lungs.
Risk factors for COPD include:
- Exposure to tobacco smoke. The most significant risk factor for COPD is long-term cigarette smoking. The more years you smoke and the more packs you smoke, the greater your risk. Pipe smokers, cigar smokers and marijuana smokers also may be at risk, as well as people exposed to large amounts of secondhand smoke.
- People with asthma. Asthma, a chronic inflammatory airway disease, may be a risk factor for developing COPD. The combination of asthma and smoking increases the risk of COPD even more.
- Occupational exposure to dusts and chemicals. Long-term exposure to chemical fumes, vapors and dusts in the workplace can irritate and inflame your lungs.
- Exposure to fumes from burning fuel. In the developing world, people exposed to fumes from burning fuel for cooking and heating in poorly ventilated homes are at higher risk of developing COPD.
- The uncommon genetic disorder (alpha-1-antitrypsin deficiency) is the cause of some cases of COPD. Other genetic factors likely make certain smokers more susceptible to the disease.
COPD can cause many complications, including:
- Respiratory infections. People with COPD are more likely to catch colds, the flu and pneumonia. Any respiratory infection can make it much more difficult to breathe and could cause further damage to lung tissue.
- Heart problems. For reasons that aren’t fully understood, COPD can increase your risk of heart disease, including heart attack
- Lung cancer. People with COPD have a higher risk of developing lung cancer.
- High blood pressure in lung arteries. COPD may cause high blood pressure in the arteries that bring blood to your lungs (pulmonary hypertension).
- Difficulty breathing can keep you from doing activities that you enjoy. And dealing with serious illness can contribute to the development of depression.
Unlike some diseases, COPD typically has a clear cause and a clear path of prevention, and there are ways to slow the progression of the disease. The majority of cases are directly related to cigarette smoking, and the best way to prevent COPD is to never smoke — or to stop smoking now.
If you’re a longtime smoker, these simple statements may not seem so simple, especially if you’ve tried quitting — once, twice or many times before. But keep trying to quit. It’s critical to find a tobacco cessation program that can help you quit for good. It’s your best chance for reducing damage to your lungs.
Occupational exposure to chemical fumes and dusts is another risk factor for COPD. If you work with these types of lung irritants, talk to your supervisor about the best ways to protect yourself, such as using respiratory protective equipment.
Here are some steps you can take to help prevent complications associated with COPD:
- Quit smoking to help reduce your risk of heart disease and lung cancer.
- Get an annual flu vaccination and regular vaccination against pneumococcal pneumonia to reduce your risk of or prevent some infections.
- Talk to your doctor if you feel sad or helpless or think that you may be experiencing depression.