Emphysema
Emphysema is a chronic lung condition in which the small air sacs of the lungs (alveoli) become permanently damaged and enlarged, reducing the lung’s ability to exchange oxygen and carbon dioxide. It is one of the main forms of chronic obstructive pulmonary disease (COPD). Emphysema is most often related to long-term cigarette smoking, but it can also be caused or worsened by environmental exposures, genetic factors, and other lung conditions. CT of the chest is the most sensitive imaging test for identifying and characterizing emphysema, while pulmonary function testing measures how much it is affecting breathing.
What is it?
The lungs contain millions of small air sacs, called alveoli, where oxygen and carbon dioxide are exchanged with the blood. In emphysema, the walls of these air sacs are damaged and break down, leading to the formation of larger, less elastic air spaces. This reduces the total surface area available for gas exchange and traps air in the lungs, making it harder to breathe—particularly to exhale efficiently. Emphysema typically develops gradually over years and is one of the main forms of chronic obstructive pulmonary disease (COPD), along with chronic bronchitis.
The most important cause of emphysema is long-term cigarette smoking. Other contributors include exposure to secondhand smoke, occupational dusts and chemicals, long-term air pollution, and certain biomass fuels used for cooking or heating in some parts of the world. A small but important minority of patients have a genetic condition called alpha-1 antitrypsin deficiency, which can cause emphysema, particularly at younger ages and in nonsmokers. Recurrent severe respiratory infections in childhood and certain rare conditions can also play a role.
Emphysema is often described by pattern on imaging. Centrilobular emphysema affects mainly the upper parts of the lungs and is the most common form associated with smoking. Panlobular emphysema involves more uniform destruction throughout the lobules and is the typical pattern in alpha-1 antitrypsin deficiency. Paraseptal emphysema affects areas of lung near the pleura, sometimes forming small subpleural blebs or bullae that can rarely rupture and cause a pneumothorax. Bullous emphysema describes the presence of larger air-filled spaces (bullae) that can compress nearby lung tissue.
Symptoms typically develop gradually over many years. Early on, people may not notice significant problems. As emphysema progresses, the most common symptom is shortness of breath, initially with exertion and later with everyday activities. Chronic cough, wheezing, chest tightness, reduced exercise tolerance, and a sensation of not being able to fully exhale are also common. Patients may experience flare-ups (exacerbations), often triggered by respiratory infections, with worsening cough, sputum production, and breathing difficulty. In more advanced disease, weight loss, fatigue, low oxygen levels, ankle swelling (from strain on the heart), and frequent infections may occur.
Pulmonary function testing is the primary tool for diagnosing COPD and emphysema. It typically shows a pattern of airflow obstruction that does not fully reverse with bronchodilators and reduced diffusing capacity—a measure of how well gas exchange is occurring. Chest X-ray may show hyperinflated lungs with flattened diaphragms and enlarged air spaces, but it is less sensitive than CT, particularly for milder disease. CT of the chest provides detailed visualization of the pattern, distribution, and severity of emphysema, and helps identify other conditions that may be present (such as lung nodules, masses, or pulmonary fibrosis). Pulse oximetry and arterial blood gases assess oxygen and carbon dioxide levels. Blood tests for alpha-1 antitrypsin are recommended in younger patients, nonsmokers with emphysema, or those with a family history.
Important to Know
Although the damage to alveoli from emphysema cannot be reversed, a great deal can be done to slow progression, improve symptoms, reduce flare-ups, and improve quality of life. The single most important step for smokers is to stop smoking, which significantly slows the rate of decline in lung function and reduces the risk of complications. Avoiding secondhand smoke and harmful occupational or environmental exposures is also important.
Inhaled medications—including long-acting bronchodilators (LABAs and LAMAs) and, in selected patients, inhaled corticosteroids—help open the airways, reduce symptoms, and decrease the frequency of flare-ups. Pulmonary rehabilitation programs combining structured exercise, education, breathing techniques, and nutritional support are highly effective in improving quality of life and exercise tolerance. Vaccinations against influenza, pneumococcal infection, COVID-19, RSV (when appropriate), and other respiratory pathogens reduce the risk of infections that can trigger exacerbations.
For patients with low oxygen levels, supplemental oxygen therapy can improve symptoms and, in qualifying patients, prolong life. In severe disease, selected patients may benefit from lung volume reduction procedures (surgical or endoscopic) or, in carefully chosen cases, lung transplantation. Acute exacerbations are treated with adjusted inhalers, antibiotics or steroids when appropriate, and supportive care; severe flare-ups may require hospitalization.
Patients with alpha-1 antitrypsin deficiency may be candidates for augmentation therapy in addition to standard treatments. Care is typically coordinated by pulmonologists, primary care clinicians, and pulmonary rehabilitation specialists, with support from respiratory therapists, dietitians, and others as needed.
Red flag symptoms include severe shortness of breath at rest, very low oxygen levels, blue lips or fingers, severe chest pain, confusion, coughing up significant blood, high fever, or sudden worsening of breathing that does not improve with usual rescue inhalers. These warrant urgent medical evaluation.