Respiratory Unit: Restrictive Pulmonary Disorders

Introduction

• Overview of Pulmonary Disorders:
  • Two categories: Obstructive and Restrictive
  • Obstructive: Difficult to get air out; Restrictive: Difficult to get air in
• Focus on Restrictive Lung Disorders

Restrictive Pulmonary Disorders

• Conceptual Overview:
  • Decreased lung expansion due to issues in:
    • Lung tissue (parenchyma or interstitial tissue)
    • Pleura
    • Chest wall
    • Neuromuscular function
• Lung Capacities & Volumes:
  • Decreased vital capacity in restrictive as opposed to obstructive
  • Lower FRC and residual volume

Arterial Blood Gases

• Normal or decreased levels of CO2 due to ability to expel air
• Decreased arterial O2 levels due to inability to expand lungs for air intake

Inflammatory Process & Lung Damage

• Fibrotic Interstitial Lung Disease:
  • Not responsible for specific conditions, but used as examples
  • Damage to alveoli and capillary beds thickens walls and deposits collagen
  • Loss of lung expandability and compliance due to fibrosis

Symptoms

• Progressive dyspnea with exercise
• Non-productive cough due to insufficient air pressure to clear mucus
• End-expiratory crackles (Velcro-like sound)
• Anorexia and weight loss due to high ATP use for breathing

Treatment

• Cessation of smoking to avoid inflammatory triggers
• Removal of exposure to irritants
• Use of anti-inflammatory and immunosuppressive agents

Hypersensitivity Pneumonitis

• Also known as Extrinsic Allergic Alveolitis
• Inflammation due to sensitivity to antigens (e.g., bird feathers, farm dust)
• Two types of hypersensitivity reactions:
  • Type 3: B-cell mediated, antigen-antibody complexes
  • Type 4: T-cell mediated, granulomatous inflammation

Occupational Lung Diseases

• Exposure to gases and particles at work (pneumoconiosis)
• Crystals deposited in lung tissue due to macrophage inability to process
• Can be symptom-free for years before discovery of lung damage

Atelectatic Disorders

• Acute Respiratory Distress Syndrome (ARDS):
  • Causes: Sepsis, aspiration of gastric acid, trauma
  • Edema and pulmonary inflammation lead to lung collapse and fibrosis
  • Hypoxemia refractory to supplemental O2 as a hallmark

Infant Respiratory Distress Syndrome (IRDS)

• Analogous to ARDS but in infants
• Primarily caused by lack of surfactant in premature births
• Treatment involves surfactant administration and supportive care

Pleural Space Disorders

• Pneumothorax:
  • Air in pleural space leads to lung collapse
  • Primary (spontaneous) vs. Secondary (caused by lung disease)
  • Tension pneumothorax as a medical emergency
• Pleural Effusion:
  • Excess fluid in pleural cavity restricting lung expansion
  • Requires thoracentesis to analyze and determine cause