questions 2

Restrictive Lung Disease Overview

Topic updated on 09/05/17 1:28pm

  • Definition
    • restricted lung expansion
    • results in reduced lung volumes (TLC and FVC)
  • Pathophysiology
    • poor breathing mechanics with normal lung function
      • muscle weakness
        • polio and myasthenia gravis
      • chest wall limitation
        • kyphosis, scoliosis, and morbid obesity
      • ↓ pleural compliance
        • mesothelioma
    • interstitial lung diseases (diffuse parenchymal lung disease - DLCO)
      • results in reduced lung compliance and increased elastic recoil 
      • the primary mechanism of resting hypoxemia in patients with interstitial lung disease is V/Q mismatch, with DLCO defect contributing to hypoxemia with activity
      • increased expiratory flow rates due to increased radial traction (result of increased elastic recoil) on airway walls
        • prevents small degree of dynamic collapse of conducting airways found in normal lungs 
      • results in ↓ in lung compliance and ↑ elastic recoil
        no relative change in ventilation/perfusion because capillaries are destroyed along with alveolar units
      • types
        • acute
          • acute interstitial pneumonia (AIP)
            • presents similar to acute respiratory distress syndrome (ARDS)
          • neonatal respiratory distress syndrome
          • drug toxicity (bleomycin, busulfan, and amiodarone)
        • chronic
          • idiopathic interstitial pneumonias
            • most common is idopathic pulmonary fibrosis (IPF)
            • non-specific interstitial pneumonia, respiratory bronchiolitis, desquamative interstitial pneumonia, cryptogenic organizing pneumonia, and lymphocytic interstitial pneumonia
          • pneumoconioses
            • coal miner's
            • silicosis
            • asbestosis
          • sarcoidosis
            • may also show obstructive or mixed pattern on PFT's
          • pulmonary Langerhans cell histiocytosis
          • hypersensitivity pneumonitis (may be acute, subacute, or chronic)
          • lymphangiomyomatosis (primarily young women)
  • Pulmonary function tests
    • FEV1 sec/FVC ratio should be normal
      • approximately normal because both FEV1 sec and FVC are reduced
    • ↓ FVC and TLC
      • key finding for restrictive lung diseases (TLC must be reduced)


Qbank (1 Questions)

(M1.PL.50) A 55-year-old male with chronic dyspnea is intubated and started on mechanical ventilation for respiratory failure. Pressure-volume scalars on the ventilator show decreased change in volume for each unit change in pressure as compared to normal values. Of the following options, which is the most likely cause of his respiratory failure? Topic Review Topic

1. Amyotrophic lateral sclerosis
2. Asthma
3. Centriacinar emphysema
4. Pulmonary fibrosis
5. Alpha-1-antitrypsin deficiency

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