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Chronic Obstructive Pulmonary Disease

Morbus pulmonis obstructivus chronicus

For medical students2 min readUpdated 2026-10-10

Chronic Obstructive Pulmonary Disease (COPD) is a progressive condition characterized by irreversible airflow limitation. The disease combines chronic bronchitis and emphysema, manifesting as excessive mucus hypersecretion, persistent cough, and progressive respiratory failure.

PrevalenceAffects approximately 20% of the male population, with incidence rates among women rapidly increasing.
Diagnostic CriteriaProductive cough lasting for at least 3 months per year for 2 consecutive years.
Level of InvolvementBronchitis affects the entire bronchial tree, whereas emphysema is strictly limited to the acinus.
MortalityFatality rates are comparable to mortality from lung cancer.

What Conditions Are Included in Obstructive Lung Diseases

The collective group of chronic obstructive pulmonary diseases traditionally includes five pathologies:

The main characteristic of this entire group is a reduction in airway caliber and an increase in resistive (non-elastic) resistance to airflow. This is driven by impaired bronchial drainage function, creating a barrier (derived from Latin obstructio — hindrance). Partial or complete obstruction can occur at any level of the respiratory tract: from the trachea down to the smallest respiratory bronchioles.

Resistance Physiology and Lung Volumes

Under normal conditions, the upper respiratory tract accounts for 80–85% of airflow resistance, with half of this load occurring in the nose. Upper airway obstruction can occur due to multiple causes: rhinitis, tumor growth, tongue drop (in coma, anesthesia, or during sleep), aspiration of fluid and foreign bodies. Additionally, the lumen may be blocked by thick sputum, thickened mucosa, edema, or laryngeal spasm (due to hysteria or inhalation of irritant gases).

Chronic obstruction drastically increases the workload on respiratory muscles, leading to rapid muscle fatigue. Vital Capacity (VC) — the maximum volume of expiration following a maximum inspiration — is typically decreased. Meanwhile, the standard tidal volume (volume of air inhaled during quiet breathing) shifts toward the inspiratory reserve volume.

Morphology and Forms of Chronic Bronchitis

The morphological substrate is chronic inflammation of the bronchial wall. The key process is hyperplasia of goblet cells and mucous glands, which begin producing excessive amounts of secretion. Clinically, this manifests as persistent sputum production.

Chronic bronchitis is divided into simple and obstructive forms. In the obstructive variant, inflammation extends to the peripheral airways (resulting in chronic bronchiolitis). Based on distribution, diffuse and local bronchitis are distinguished. The local form most frequently affects the right lung, specifically the bronchi of the 2nd, 4th, 8th, 9th, and 10th segments.

Relationship Between Bronchitis and Emphysema

Chronic bronchitis and emphysema have distinct anatomical and diagnostic differences. Bronchitis is identified based on clinical features and involves the entire bronchial tree. Emphysema is defined by morphological changes, and its localization is strictly restricted to the acinus.

These pathologies may exist in isolation (e.g., pure emphysema in hereditary $\alpha_1$-antitrypsin deficiency). In clinical practice, however, they almost always coexist. Their development stems from the interaction of risk factors and cellular-molecular mechanisms. For this reason, clinicians group them under a single nosology: COPD.

Mnemonic

To avoid confusing COPD and asthma, remember a simple rule: COPD is a Chronic and Irreversible obstruction, whereas Asthma is an Attack with Reversible spasm.

Frequently asked questions

What microscopic changes in the bronchial wall are characteristic of chronic bronchitis?

Microscopic changes in the bronchial wall in chronic bronchitis are associated with chronic mucous or purulent catarrhal inflammation.

The following abnormalities are observed:

  • Epithelial changes — metaplasia of the lining epithelium, goblet cell hyperplasia, and hypertrophy of bronchial mucous glands.
  • Structural changes — marked inflammatory infiltration, proliferation of granulation tissue with potential formation of mucosal inflammatory polyps, as well as sclerosis and atrophy of the muscle layer.
What macroscopic changes in the lungs are characteristic of chronic obstructive emphysema?

Macroscopically in chronic obstructive emphysema, the lungs are significantly increased in size and cover the anterior mediastinum with their margins.

The following features are characteristic:

  • Tissue state — the lung parenchyma becomes hyperinflated, pale, and soft.
  • Behavior during autopsy — the lungs do not collapse upon opening the chest cavity.
  • Sound phenomena — a characteristic crepitus is heard when cutting the tissue.
  • Bronchial changes — mucopurulent exudate is expressed from the bronchial lumens upon compression.
What morphological types of pulmonary emphysema are distinguished based on acinar involvement?

Depending on acinar involvement, morphological types of emphysema include:

  • Panacinar emphysema — both central and peripheral parts of the acinus are involved, meaning the entire acinus is affected.
  • Paraseptal emphysema — only the distal portion of the acinus is altered, while the proximal portion remains unaffected.
  • Centriacinar emphysema — distinguished as a separate type based on the affected zone of the acinus.
  • Irregular emphysema — characterized by uneven involvement of the acinus.
What pulmonary and extrapulmonary complications are most characteristic of COPD?

COPD is characterized by a progressive course with the development of severe pulmonary and cardiovascular complications.

Major complications include:

  • Respiratory failure — progressive impairment of pulmonary ventilation and gas exchange.
  • Hemodynamic disturbances — pulmonary arterial hypertension and right ventricular hypertrophy.
  • Cardiac pathology — development of cor pulmonale and progressive cardiopulmonary failure.
  • Bulla-related complications — in the presence of bullous emphysema, pneumothorax, hemorrhage from the bulla, and bullous infection may occur.
What is the main difference between COPD and bronchial asthma?

In COPD, airway obstruction is primary and irreversible. In contrast, bronchial asthma is characterized by reversible obstruction.

What genetic factors contribute to the development of COPD?

The disease can develop against the background of hereditary pathologies. Classic examples include cystic fibrosis and immotile cilia syndrome (Kartagener syndrome).

What is the epidemiological picture of the disease?

It is the most common chronic lung disease, affecting about 20% of men. An increase in incidence among women is noted due to cigarette smoking, and mortality rates are comparable to those of lung cancer.

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