125 lecture

Diagnosis of Pulmonary Disorders

• Diagnosing conditions like COPD or restrictive disorders involves differentiating between obstructive and restrictive issues using spirometry or pulmonary function tests (PFTs).

Spirometry and Pulmonary Function Tests

• Spirometry: A key breathing test measuring airflow and lung volumes.

  • Provides vital capacity and other respiratory values.

  • Vital Capacity (VC): The maximum volume of air that can be inhaled and exhaled.

    • Forced Vital Capacity (FVC): VC with a forceful exhalation after a maximal inhalation. This is the key measurement used in diagnosing obstructive diseases.

Key Measurements in Pulmonary Function Tests

• FEV1: Forced Expiratory Volume in one second.

  • Healthy individuals exhale all air in about two seconds.

  • Patients with obstructive disorders struggle to exhale due to airway resistance.

  • The FEV1/FVC ratio indicates lung function:

    • Normal FEV1/FVC is usually over 70%.

    • Ratios under 70% indicate obstructive disorders.

• Restrictive Disorders: Conditions (e.g., pulmonary fibrosis) that limit lung expansion, reducing the overall volume of air that can be inhaled and exhaled.

  • The overall lung capacity could be low even if FEV1 appears normal relative to FVC.

Obstructive vs Restrictive Disorders

• Obstructive Diseases: Characterized by decreased expiratory flow rates.

  • Conditions include COPD, which entails difficulty in exhaling air due to airway blockages.

• Restrictive Diseases: Characterized by reduced lung volumes.

  • Difficulties arise in achieving good tidal volumes due to lung capacity restrictions, either from physical compression or disease (e.g., fibrosis).

Classification of Pulmonary Disorders

• Pulmonary disorders can broadly be classified into:

  • Obstructive Diseases: Involve increased resistance during expiration and are often partially reversible with bronchodilators.

  • Restrictive Diseases: Involve decreased air volume in the lungs, especially affecting inspiratory capacity.

    • Examples include pulmonary fibrosis, ARDS, and lung cancer.

Risk Factors for COPD

• Primary Causes:

  • Cigarette smoking and alpha-1 antitrypsin deficiency are the most common risk factors.

  • Smoking:

    • Disrupts ciliary function, leading to mucus buildup.

    • Leads to bronchospasm and decreased macrophage activity, resulting in increased susceptibility to infections.

• Environmental Factors:

  • Air pollution, secondhand smoke, occupational hazards, chronic lung infections also contribute.

• Genetic Factors:

  • Individuals with alpha-1 antitrypsin deficiency are at higher risk for developing emphysema-like conditions.

  • Other hereditary lung diseases ( e.g., cystic fibrosis) can also lead to COPD over time.

Treatment and Management of COPD

• Treatment strategies depend on severity categorized by FEV1/FVC ratios:

  • Mild: Short-acting bronchodilators as needed.

  • Moderate: Regular use of long-acting bronchodilators and continued short-acting as needed.

  • Severe: Incorporation of corticosteroids to manage inflammation.

• Rehabilitation: Includes pulmonary rehab programs focusing on breathing techniques, such as pursed-lip breathing.

Disorders Qualifying as COPD

• Disorders classified under COPD include:

  • Chronic Bronchitis

  • Emphysema

  • Asthma

  • Cystic Fibrosis

  • Bronchiectasis

  • Bronchiolitis

• Understanding these conditions is essential for proper categorization and preparing for examination and treatment protocols.