Emphysema: A Brief Overview

Pulmonary emphysema is a pathological condition characterized by irreversible dilation of the airspaces distal to the terminal bronchioles, with destruction of the interalveolar septa without significant fibrosis. This leads to decreased elastic recoil of the parenchyma, air trapping, impaired gas exchange, and progressive dyspnea. The term is often used in the context of chronic obstructive pulmonary disease, but emphysema specifically emphasizes the alveolar component of the damage. Understanding the morphology, risk factors, and mechanisms of the disease is important for selecting treatment strategies, ranging from lifestyle modification and inhalation pharmacotherapy to interventional and surgical methods. [1]

Emphysema develops over years and is characterized by clinical and morphological heterogeneity. Centrilobular, panlobular, and paraseptal forms exist, as well as bullous changes. Some patients experience predominantly symptoms of exertion and decreased tolerance to physical activity, while others experience frequent exacerbations and complications. Early detection and risk stratification are important, including the identification of alpha-1 antitrypsin deficiency as a potentially modifiable cause in some patients. [2]

Epidemiology

Emphysema, as part of the spectrum of chronic obstructive pulmonary disease, remains a significant cause of morbidity and mortality worldwide. Prevalence varies by country and age group, increasing with age and smoking history. Estimates of the disease burden are being refined as access to spirometry and high-resolution computed tomography improves. [3]

Tobacco smoking remains the leading determinant of population prevalence, but the contributions of occupational exposures, air pollution, and biomass are increasing. Areas with high exposure to household smoke from solid fuels have a higher prevalence of chronic obstructive pulmonary disease and emphysema in nonsmokers, particularly women. [4]

The detection rate of emphysema is increasing with the widespread use of low-dose computed tomography, including in lung cancer screening programs. This allows for the identification of a phenotype with predominant alveolar destruction and the selection of targeted interventions, such as lung volume reduction. [5]

Gene and protein markers, including alpha-1 antitrypsin deficiency, account for a smaller proportion of cases but significantly influence the onset of the disease at a young age and the rate of progression. Targeted testing improves diagnosis and the selection of specific therapy. [6]

Reasons

The main cause is prolonged inhalation exposure to toxic particles and gases. Active smoking, as well as passive smoking, play a leading role. Occupational aerosols, dust, chemical agents, and outdoor and household air pollution also contribute. [7]

Genetic factors include alpha-1 antitrypsin deficiency, in which failure of protease inhibition enhances elastolytic damage to alveolar structures. Phenotypes with severe deficiency and early onset of symptoms are of clinical significance. [8]

Anatomical and immunobiological mechanisms interact with environmental factors: oxidative stress, imbalance of proteases and antiproteases, tissue repair disorders, which leads to progressive destruction of septa. [9]

Less commonly, the cause is repeated infections and inflammation in concomitant conditions leading to remodeling of the distal respiratory tract, as well as the consequences of bullous transformation. [10]

Risk factors

Non-modifiable factors include age, gender, hereditary variants, including alpha-1 antitrypsin deficiency, and family history. Early onset of symptoms and multiple cases of chronic obstructive pulmonary disease in relatives increase the likelihood of a genetic contribution. [11]

Modifiable factors include active and passive smoking, occupational hazards, air pollution, including indoor air pollution, and repeated respiratory tract infections. [12]

Additional risk factors include low physical activity, malnutrition, or sarcopenia, which worsen the prognosis and increase the likelihood of exacerbations. Correction of these factors is part of comprehensive rehabilitation. [13]

Table 1. Key risk factors for emphysema and the level of modifiability

Factor	Category	Modifiability	Comment
Smoking	External	High	The main goal of termination
Professional aerosols	External	Average	Depends on environmental control
Air pollution	External	Average	Affects symptoms
Alpha-1 antitrypsin deficiency	Interior	Low	Requires specific management
Sarcopenia	Interior	Average	Corrected by rehabilitation

Pathogenesis

The underlying cause is an imbalance of proteases and antiproteases against a background of oxidative stress and chronic inflammation. Excessive activity of elastases and matrix metalloproteinases destroys the elastic framework of lung tissue. Alpha-1-antitrypsin deficiency exacerbates this process, accelerating alveolar destruction. [14]

Loss of elastic recoil leads to premature collapse of the small airways during exhalation, air trapping, and hyperinflation. This reduces respiratory efficiency, increases respiratory muscle workload, and causes dynamic hyperinflation during exercise. [15]

Destruction of the alveolar-capillary membrane reduces diffusion capacity, increases physiological dead space, and leads to hypoxemia during exercise and, in later stages, at rest. Bullae formation can further compress the remaining parenchyma. [16]

Phenotypic heterogeneity reflects differences in the distribution of lesions: the upper lobe centrilobular form is characteristic of smokers, the panlobular form is characteristic of alpha-1-antitrypsin deficiency, and the paraseptal form is associated with the risk of spontaneous pneumothorax. These differences are important when selecting for reductive interventions. [17]

Symptoms

The most typical presentation is progressive shortness of breath, initially with exertion and then at rest. Patients describe decreased tolerance for physical activity, the need to pause while walking, and difficulty climbing stairs. A nonproductive cough and wheezing are often associated. [18]

Progressive hyperinflation is manifested by a feeling of "incomplete exhalation," involvement of accessory muscles, prolonged exhalation, and a barrel chest. On examination, decreased breath sounds, prolonged exhalation, and a box-like appearance to percussion are noted. [19]

During exacerbations, shortness of breath and cough increase, and the character of sputum changes. Symptoms of concomitant cardiovascular pathology, including pulmonary hypertension and edema, may occur, which influences the prognosis and choice of therapy. [20]

In some patients, symptoms develop gradually, their severity correlates poorly with the degree of anatomical destruction, therefore instrumental verification is necessary. [21]

Forms and stages

Morphological patterns include centriacinar, panacinar, paraseptal, and irregular. Localization and heterogeneity are important in assessing candidates for lung volume reduction.[22]

Clinical staging is often linked to the degree of obstruction measured by spirometry after bronchodilator use, the severity of symptoms, and the frequency of exacerbations. Current guidelines use combined risk and symptom groups to select drug therapy. [23]

High-resolution computed tomography allows quantitative assessment of the proportion of low-density tissue, the distribution of lesions and the presence of bullae, which influences the choice of interventional treatment. [24]

Table 2. Morphological forms of emphysema and clinical and practical significance

Form	Typical profile	Importance for practice
Centrilobular	Smoking, upper lobes	Common candidates for volume reduction
Panlobular	Alpha-1 antitrypsin deficiency	Uniform defeat, different selection for interventions
Paraseptal	Young, subpleural	Risk of pneumothorax
Irregular	After inflammation	Heterogeneous changes

Complications and consequences

Key complications include bullous disease with the risk of spontaneous pneumothorax, frequent exacerbations, respiratory failure, pulmonary hypertension, and chronic cor pulmonale. These conditions increase hospitalization and mortality. [25]

Systemic consequences include sarcopenia, osteoporosis, depression, and cardiovascular events. Current guidelines emphasize the assessment and treatment of comorbidities as part of a comprehensive management strategy. [26]

Long-term hypoxemia leads to polycythemia, cognitive impairment, and decreased quality of life. Oxygenation correction in carefully selected patients improves survival and functional outcomes. [27]

Complications such as air leakage after lung volume reduction and infectious events may occur after interventions, which requires center experience and strict selection criteria. [28]

Diagnostics

Spirometry demonstrates irreversible airflow limitation. For the emphysema phenotype, decreased pulmonary diffusion capacity, signs of hyperinflation, and air trapping on plethysmography are important. [29]

High-resolution computed tomography confirms alveolar destruction, determines localization and heterogeneity, identifies bullae, assesses interlobar septa and collateral ventilation indirectly, which is critical when planning endobronchial valve reduction. [30]

A single targeted alpha-1 antitrypsin deficiency test is recommended for all patients with chronic obstructive pulmonary disease, particularly in early-onset, familial, lower-lobe panlobular, and non-smokers. This changes management strategies and opens the possibility of replacement therapy. [31]

Symptom assessment is performed using standardized questionnaires, 6-minute walk tests, and cardiopulmonary testing as indicated. The risk profile for exacerbations and comorbidities determines the intensity of monitoring and treatment. [32]

Table 3. Diagnostic tests for emphysema

Method	What does it show?	Practical application
Spirometry	Airflow restriction	Confirmation of chronic obstructive pulmonary disease
Diffusion capacity	Decreased gas exchange	Severity of alveolar destruction
Plethysmography	Hyperinflation, residual volume	Rehabilitation and therapy planning
High-resolution computed tomography	Morphology and localization	Selection for lung volume reduction
Alpha-1 antitrypsin genetic testing	Deficit	Indications for replacement therapy

Differential diagnosis

Bronchial asthma with predominantly reversible obstruction and bronchial hyperreactivity should be excluded. In elderly patients, a combination of conditions is possible, which requires tests with bronchodilators and anamnesis analysis. [33]

It is necessary to differentiate between interstitial lung diseases, especially pulmonary fibrotic processes with a component of emphysema in the upper lobes, as well as the consequences of tuberculosis and post-inflammatory changes. High-resolution computed tomography is crucial. [34]

Cardiovascular causes of dyspnea and decreased exercise tolerance, including heart failure and pulmonary hypertension, should be assessed in parallel, as they alter the prognosis and therapeutic strategy.[35]

Table 4. Comparison of key features

State	Obstruction	Diffusion capacity	High-resolution computed tomography	Response to bronchodilators
Emphysema	Constant	Lowered	Low-density zones, bullae	Limited
Asthma	Variable	Norm	Peribronchial changes	Expressed
Interstitial diseases	Possible	Low	Reticulocellular pattern	Short
Heart failure	Absent	Norm	Stagnation	Short

Treatment

The basic strategy includes smoking cessation, vaccination, pulmonary rehabilitation, inhaled pharmacotherapy, oxygen therapy when indicated, and interventional methods in selected patients. Smoking cessation is the most effective intervention in slowing the decline of lung function. [36]

Pharmacotherapy is selected based on symptoms and the risk of exacerbations: long-acting bronchodilators from the beta-2 receptor agonist and muscarinic receptor antagonist groups, and, if necessary, a combination of these; the addition of inhaled corticosteroids in patients with frequent exacerbations and elevated blood eosinophils. A phosphodiesterase-4 inhibitor is considered in patients with chronic bronchitis and frequent exacerbations. [37]

Pulmonary rehabilitation with endurance and strength training, breathing exercises, and nutritional support improves exercise tolerance, reduces shortness of breath, and the risk of hospitalization. Maintenance programs are essential for lasting results. [38]

In patients with severe hypoxemia, long-term oxygen therapy is prescribed at rest, which improves survival. Monitoring includes measurement of oxygen saturation and arterial blood gas composition. [39]

Specific therapy for alpha-1 antitrypsin deficiency is intravenous replacement therapy with alpha-1 antitrypsin preparations, indicated for strictly selected non-smoking patients with severe deficiency. Real-world data suggest a survival benefit with appropriate selection. [40]

Interventional lung volume reduction techniques include surgical reduction and endobronchial valves in patients with severe hyperinflation and heterogeneous lesion distribution in the absence of collateral ventilation. Randomized trials have shown improvements in function, tolerability, and quality of life with appropriate selection and high center expertise. [41]

Table 5. Pharmacotherapy and non-pharmacological interventions

Direction	Examples	Who is it indicated for?	Expected effect
Long-acting bronchodilators	Beta-2 agonist, muscarinic receptor antagonist	Symptomatic patients	Reduction of shortness of breath
Inhaled corticosteroids	As part of triple therapy	Frequent exacerbations, eosinophilia	Reduction of exacerbations
Phosphodiesterase-4 inhibitor	Roflumilast	Chronic bronchitis with exacerbations	Reduction of exacerbations
Pulmonary rehabilitation	Training, education	Most patients	Improving tolerability
Oxygen therapy	Home	Severe hypoxemia	Improving survival
Alpha-1 antitrypsin replacement therapy	Intravenously	Alpha-1 antitrypsin deficiency	Slowing down progression
Reduction of lung volume	Surgery, valves	Selected patients with hyperinflation	Functional improvement

Table 6. Selection for lung volume reduction: guidelines

Criterion	Surgical reduction	Endobronchial valves
Distribution of damage	Upper lobe, heterogeneous	Heterogeneous and part of uniform
Collateral ventilation	Not critical	Must be absent from the target share
Risk of complications	Operational risks	Risk of air leakage
Expected effect	Function and portability	Function, quality of life

Prevention

Primary prevention focuses on preventing inhalational exposures: stopping smoking, reducing occupational hazards, and improving indoor and outdoor air quality. Vaccination against influenza, pneumococcal infection, and other respiratory pathogens reduces the risk of exacerbations and complications. [42]

Secondary prevention aims to slow down the progression in those already ill: support for sustainable smoking cessation, rehabilitation programs, control of comorbidities, timely correction of hypoxemia, training in self-management and early escalation of therapy at signs of exacerbation. [43]

Forecast

The prognosis depends on age, smoking history, degree of obstruction, severity of hyperinflation, level of diffusion capacity, frequency of exacerbations, and the presence of comorbidities, including cardiovascular disease and pulmonary hypertension. Comprehensive intervention can stabilize symptoms and improve quality of life. [44]

In carefully selected patients, interventional lung volume reduction techniques provide sustained improvement in function and symptoms, and in alpha-1 antitrypsin deficiency, replacement therapy is associated with improved survival in real-world practice. A personalized approach and follow-up in experienced centers are critical for outcomes. [45]

FAQ

• What is the most important thing to do at the beginning of treatment?

Smoking cessation and appropriate inhalation therapy based on symptoms and risk of exacerbations, plus vaccination and rehabilitation, make the greatest contribution to slowing progression and improving quality of life. [46]

• Who should be tested for alpha-1 antitrypsin deficiency?

All patients with chronic obstructive pulmonary disease (COPD) should be tested at least once, especially those with early onset, a family history, and the lower lobe panlobular type. A positive result opens the way to specific replacement therapy. [47]

• When to consider lung volume reduction?

In cases of severe hyperinflation and decreased quality of life despite optimal drug therapy and rehabilitation, in the presence of anatomical criteria based on high-resolution computed tomography and functional criteria. The decision is made by a multidisciplinary team. [48]

• Do endobronchial valves provide a lasting effect?

Randomized trials show clinically meaningful improvements for up to 12 months, and extended follow-up studies report maintenance of benefit for up to 5 years in some patients with proper selection.[49]

• Can emphysema be completely cured?

Emphysema is irreversible, but its progression can be significantly slowed and symptoms can be controlled. Modern therapies and interventions improve exercise tolerance, reduce exacerbations, and enhance quality of life. [50]