Respiratory Diseases & Disorders

This section provides an overview of common respiratory diseases and disorders, focusing on their causes, pathophysiology, and clinical features. Understanding these conditions is essential for recognizing their impact on the respiratory system and overall health.

Asthma Attacks

Asthma is a chronic inflammatory disease of the airways characterized by episodes of airway narrowing and obstruction, leading to breathing difficulties.

• Pathophysiology: Asthma involves bronchoconstriction, airway inflammation, and increased mucus production. During an attack, the smooth muscle around the bronchi contracts, the airway lining swells, and excess mucus is produced, narrowing the airways.

• Triggers: Common triggers include allergens, exercise, cold air, respiratory infections, and air pollutants.

• Symptoms: Wheezing, shortness of breath, chest tightness, and coughing, especially at night or early morning.

• Diagram Explanation: The provided images show the difference between a normal airway and an asthmatic airway, highlighting the constricted smooth muscle, inflamed lining, and mucus buildup.

• Treatment: Inhaled bronchodilators and corticosteroids are commonly used to relieve symptoms and control inflammation.

Example: A person with asthma may experience an attack after exposure to pollen, resulting in sudden wheezing and difficulty breathing.

Chronic Obstructive Pulmonary Disease (COPD)

COPD is a group of progressive lung diseases, primarily including chronic bronchitis and emphysema, that cause airflow blockage and breathing-related problems.

Etiology and Risk Factors

• Tobacco smoke is the leading cause of COPD.

• Air pollution and occupational exposures also contribute.

• α-1 antitrypsin deficiency is a genetic risk factor for emphysema.

Pathophysiology

• Chronic Bronchitis: Characterized by continual bronchial irritation and inflammation, leading to bronchial edema, chronic productive cough, and bronchospasm.

• Emphysema: Involves the destruction of alveolar walls, loss of lung elasticity, and air trapping due to the breakdown of elastin in lung connective tissue.

• Common Features: Airway obstruction or air trapping, dyspnea (difficulty breathing), frequent respiratory infections, and abnormal ventilation-perfusion ratio.

• Clinical Consequences: Hypoxemia (low blood oxygen), hypoventilation (reduced air movement), and increased risk of respiratory failure.

Clinical Presentation: "Pink Puffer" vs. "Blue Bloater"

• "Pink Puffer" (Emphysema dominant): Patients often have a thin appearance, use accessory muscles to breathe, and maintain relatively normal oxygenation (hence "pink"). They struggle to breathe but do not typically develop cyanosis early.

• "Blue Bloater" (Chronic Bronchitis dominant): Patients may be overweight, have a chronic productive cough, and develop cyanosis (bluish skin) due to hypoxemia. They are less likely to struggle for breath but have more pronounced oxygen deficiency.

Additional info: The terms "pink puffer" and "blue bloater" are classic clinical descriptions but may overlap in real patients.

Summary Table: COPD Pathogenesis and Features

Lung Cancer and Metastasis

Lung cancer is a malignant tumor arising from the tissues of the lung, often associated with smoking and exposure to carcinogens.

• Etiology: Major risk factors include tobacco smoke, air pollution, and occupational exposures (e.g., asbestos).

• Pathophysiology: Cancerous cells grow uncontrollably, invade surrounding tissues, and can metastasize (spread) to other organs.

• Symptoms: Persistent cough, hemoptysis (coughing up blood), chest pain, weight loss, and recurrent respiratory infections.

• Metastasis: Lung cancer commonly spreads to the brain, bones, liver, and adrenal glands.

Example: A patient with a history of smoking presents with a chronic cough and unexplained weight loss; imaging reveals a mass in the lung with evidence of spread to the liver.

Key Terms and Definitions

• Dyspnea: Difficult or labored breathing.

• Hypoxemia: Abnormally low concentration of oxygen in the blood.

• Hypoventilation: Reduced rate and depth of breathing, leading to increased carbon dioxide in the blood.

• Bronchospasm: Sudden constriction of the muscles in the walls of the bronchioles.

• Air trapping: Incomplete emptying of alveoli during expiration, leading to increased residual air volume.