Chronic Obstructive Pulmonary Disease (COPD)
A progressive lung disease that makes breathing increasingly difficult
Table of Contents
Overview
Chronic Obstructive Pulmonary Disease (COPD) is a group of progressive lung diseases that obstruct airflow from the lungs. The most common conditions that make up COPD are emphysema and chronic bronchitis. Many people with COPD have both conditions.
COPD causes breathing difficulties that worsen over time. The airways and air sacs in the lungs lose their elastic quality, the walls between air sacs are destroyed, airways become inflamed and produce excess mucus, and breathing passages may become partially blocked. These changes result in reduced airflow both in and out of the lungs.
COPD is a leading cause of disability and death worldwide. According to the World Health Organization, more than 3 million people died from COPD in 2019, representing 6% of all deaths globally. In the United States, COPD affects more than 16 million adults and is the fourth leading cause of death. Many more people may have the disease without knowing it, as COPD develops slowly and symptoms often don't appear until significant lung damage has occurred.
Types of COPD
Emphysema
Emphysema involves damage to the air sacs (alveoli) in the lungs. The inner walls of the air sacs weaken and rupture, creating larger air spaces instead of many small ones. This reduces the surface area of the lungs and the amount of oxygen that reaches the bloodstream. The damaged alveoli also make it harder to breathe out, trapping air in the lungs.
Chronic Bronchitis
Chronic bronchitis is inflammation of the lining of the bronchial tubes, which carry air to and from the lungs. This inflammation causes excessive mucus production and a chronic cough. The bronchial tubes become swollen and narrowed, making it difficult to breathe. Chronic bronchitis is defined as a productive cough that lasts at least three months, with recurring episodes for at least two consecutive years.
Refractory (Non-reversible) Asthma
Some people with severe asthma may develop COPD-like symptoms that don't respond to typical asthma medications. This type of asthma, also called non-reversible asthma, involves permanent narrowing of the airways that doesn't improve with bronchodilators.
Alpha-1 Antitrypsin Deficiency
A rare genetic form of emphysema caused by a deficiency of alpha-1 antitrypsin, a protein that protects the lungs. Without enough of this protein, the lungs are vulnerable to damage, leading to COPD at a younger age, typically between ages 30-40.
Symptoms
COPD symptoms often don't appear until significant lung damage has occurred, and they usually worsen over time, particularly if smoking exposure continues:
Respiratory Symptoms
Associated Symptoms
Progressive Symptoms
- Exercise intolerance: Difficulty performing physical activities that were once easy
- Frequent respiratory infections: Colds, flu, and pneumonia
- Morning headaches: Due to decreased oxygen levels during sleep
- Weight loss: In advanced stages due to increased energy needed to breathe
- Swelling: In ankles, feet, or legs due to heart strain
- Cyanosis: Bluish color of lips or fingernails from low oxygen
COPD Exacerbations
People with COPD may experience episodes called exacerbations or flare-ups when symptoms become worse than usual and last for several days. Signs include:
- Increased breathlessness
- More frequent or severe coughing
- Changes in sputum color or amount
- Increased fatigue
- Fever
- Confusion or decreased alertness
Causes and Risk Factors
COPD develops from long-term exposure to irritating gases or particulate matter that damage the lungs and airways:
Primary Causes
- Cigarette smoking: Responsible for 85-90% of COPD cases in developed countries
- Secondhand smoke: Long-term exposure increases risk significantly
- Occupational exposures: Dust, chemicals, and fumes in the workplace
- Indoor air pollution: From biomass fuel burning for cooking and heating
- Outdoor air pollution: Vehicle exhaust, industrial emissions
- Genetic factors: Alpha-1 antitrypsin deficiency
Risk Factors
- Age: Most people are at least 40 when symptoms begin
- Smoking history: Risk increases with pack-years (packs per day × years smoked)
- Asthma: Combination of asthma and smoking increases COPD risk
- Childhood respiratory infections: May increase susceptibility
- Socioeconomic status: Lower status linked to higher risk
- Gender: Historically more common in men, but rates in women increasing
Occupational Hazards
- Coal mining
- Construction work
- Manufacturing (textiles, rubber, leather)
- Agriculture (grain dust, animal confinement)
- Welding and metal work
Stages of COPD
COPD is classified into stages based on severity of airflow limitation and symptoms:
Stage 1: Mild COPD
- FEV1 ≥ 80% of predicted normal
- Mild airflow limitation
- May have chronic cough and sputum production
- Person may not realize lung function is abnormal
Stage 2: Moderate COPD
- FEV1 50-79% of predicted normal
- Worsening airflow limitation
- Shortness of breath during exertion
- Patients typically seek medical attention at this stage
Stage 3: Severe COPD
- FEV1 30-49% of predicted normal
- Further worsening of airflow limitation
- Greater shortness of breath, reduced exercise capacity
- Fatigue and repeated exacerbations
Stage 4: Very Severe COPD
- FEV1 < 30% of predicted normal or < 50% with chronic respiratory failure
- Severe airflow limitation
- Quality of life significantly impaired
- Exacerbations may be life-threatening
Diagnosis
COPD diagnosis involves several tests to assess lung function and rule out other conditions:
Diagnostic Tests
Spirometry
The most important test for COPD diagnosis. Measures how much air you can inhale and exhale, and how quickly you can exhale. A FEV1/FVC ratio less than 0.70 confirms airflow limitation.
Chest X-ray
Can show emphysema and rule out other lung problems or heart failure. May appear normal in early COPD.
CT Scan
Provides detailed images of lungs, can detect emphysema earlier than X-rays and help plan for surgery if needed.
Arterial Blood Gas Analysis
Measures oxygen and carbon dioxide levels in blood to determine if you need oxygen therapy.
Alpha-1 Antitrypsin Test
Blood test to check for genetic form of emphysema, especially in younger patients or those with family history.
Additional Assessments
- Exercise testing: Six-minute walk test to assess functional capacity
- Pulse oximetry: Non-invasive measurement of oxygen saturation
- Sputum examination: To identify bacterial infections
- ECG and echocardiogram: To assess heart involvement
Treatment
While COPD can't be cured, treatments can relieve symptoms, improve quality of life, and slow disease progression:
Medications
Bronchodilators
Medications that relax muscles around airways:
- Short-acting: Albuterol, ipratropium for quick relief
- Long-acting: Tiotropium, salmeterol for daily control
- Combination: LABA/LAMA combinations for better control
Inhaled Corticosteroids
Reduce airway inflammation. Often combined with long-acting bronchodilators for people with frequent exacerbations.
Oral Medications
- Phosphodiesterase-4 inhibitors: Reduce inflammation
- Theophylline: Helps improve breathing (less commonly used)
- Antibiotics: For bacterial respiratory infections
- Oral steroids: For severe exacerbations
Therapies
Oxygen Therapy
Supplemental oxygen for those with low blood oxygen levels. May be needed continuously or only during activities or sleep.
Pulmonary Rehabilitation
Comprehensive program including:
- Exercise training
- Nutritional counseling
- Education about COPD
- Psychological counseling
Non-invasive Ventilation
Breathing support through a mask, used for severe COPD with high carbon dioxide levels.
Surgical Options
Lung Volume Reduction Surgery
Removes damaged lung tissue to help remaining tissue work better.
Lung Transplant
For severe COPD when other treatments have failed and life expectancy is limited.
Bullectomy
Removal of large air spaces (bullae) that interfere with breathing.
Living With COPD
Managing COPD requires lifestyle adjustments and ongoing self-care:
Daily Management
- Medication adherence: Use inhalers correctly and as prescribed
- Monitor symptoms: Keep track of breathing changes and exacerbation signs
- Energy conservation: Plan activities to avoid overexertion
- Breathing techniques: Practice pursed-lip and diaphragmatic breathing
- Stay active: Regular exercise within your limits
Environmental Modifications
- Avoid irritants: Smoke, strong perfumes, cleaning products
- Control humidity: Use humidifier or dehumidifier as needed
- Air quality: Monitor outdoor air quality, stay indoors on bad days
- Temperature: Avoid extreme hot or cold weather
- Allergen control: Minimize dust, pet dander, mold
Nutrition and Health
- Healthy weight: Being overweight or underweight affects breathing
- Small frequent meals: Large meals can press on diaphragm
- Adequate fluids: Helps thin mucus secretions
- Limit salt: Reduces fluid retention
- Nutritional supplements: If weight loss is a problem
Emotional Well-being
- Manage anxiety: Breathing difficulties can trigger anxiety
- Depression screening: Common in chronic illness
- Support groups: Connect with others who have COPD
- Counseling: Professional help for coping strategies
Prevention
Many cases of COPD are preventable through avoiding risk factors:
Primary Prevention
- Don't smoke: Never start smoking or quit as soon as possible
- Avoid secondhand smoke: Protect yourself from others' smoke
- Workplace safety: Use protective equipment around dust and chemicals
- Indoor air quality: Ensure good ventilation when cooking or heating
- Vaccinations: Annual flu shots and pneumonia vaccines
Slowing Progression
For those already diagnosed with COPD:
- Smoking cessation: Most important step to slow progression
- Medication compliance: Take medications as prescribed
- Regular exercise: Maintains lung function and overall health
- Avoid infections: Hand hygiene, avoid crowds during flu season
- Regular monitoring: Keep all medical appointments
Complications
COPD can lead to several serious complications:
Respiratory Infections
People with COPD are more susceptible to colds, flu, and pneumonia. These infections can make breathing much more difficult and cause further lung damage.
Heart Problems
COPD increases risk of heart disease, including heart attack. Low oxygen levels strain the heart, potentially leading to right-sided heart failure (cor pulmonale).
Lung Cancer
People with COPD have a higher risk of developing lung cancer, particularly if they smoke or have a history of smoking.
Pulmonary Hypertension
High blood pressure in the arteries that bring blood to the lungs, caused by narrowing of these vessels.
Depression and Anxiety
Difficulty breathing can limit activities and lead to social isolation, contributing to mental health issues.
Respiratory Failure
Severe COPD can lead to inability to breathe adequately on your own, requiring mechanical ventilation.