7. Emphysema & Chronic Bronchitis - Cox

• COPD subset - triad

  • emphysema
  • chronic bronchitis
  • asthma - transient
• Chronic Obstructive pulmonary disease (COPD) - airway restriction causing respiratory issues
• COPD - typical symptoms

  • cough
  • breathlessness
  • wheeze
• Global initiative for chronic obstructive lung disease defines

  • airflow limitation that is not fully reversible
  • abnormal inflammatory response to inhaled noxious gases
  • usually progressive
• COPD pathophysiology

  • airflow obstruction due to
  • inflammation, fibrosis -> airway narrowing
  • excess mucus production -> airway obstruction
  • disrupted airway structural support -> airway collapse
• Emphysema - abnormal permanent air space enlargement distal to terminal bronchioles
• Classical key concept of emphysema - irreversible acinar damage
• Emphysematous process - alveolar septal destruction --> elastin degradation

  • alveolar wall destruction leading to
  • impaired expiratory airflow
  • progressive alveoli air trapping
  • impairs gas exchange
• emphysema can lead to alveolar wall destruction that can cause alveoli air trapping

  • alveolar hyperinflation or ballooning
• What is an established risk factor for emphysema?

  smoking
• what gene can lead to emphysema?

  alpha-1 antitrypsin deficiency (AATD)
• Emphysema pathophysiology - due to inflammatory reaction

  1. reactive oxygen species
  2. immune mediated tissue damage
  3. proteolytic matrix metalloproteinase
  4. elastase
  5. proteolytic elastin degradation
• emphysema - immune mediated reaction will cause remodeling

  • leading to airway narrowing
  • due to smooth muscle hypertrophy
  • goblet cell hyperplasia --> mucus hypersecretion
• Emphysema remodeling will cause small airway narrow in expiration

  • leading to outflow obstruction
  • decrease elastin - which normally maintain airway during expiration
  • increase mucous secretion - plug airway
• Emphysema will cause poor expulsion of air during expiration

  • air trapped in alveoli
  • **hyperinflation
• Emphysema - air trapping

  • diminished structural/tethering support --> impaired alveolar expiration
  • trapping worsen by mucus build up --> ** expiratory plugging
  • air becomes trapped in alveoli causing alveolar hyperinflation
• Emphysema - gross - can be described as

  • alveolar wall destruction - thin and delicate walls without intervening fibrosis
  • honeycomb fibrosis subpleural lung parenchyma
• Emphysema - honeycomb fibrosis subpleural lung parenchyma

  • abnormal air spaces due to alveolar wall destruction and dilation
  • small airways separated by fibrous bands tissue
• Emphysema - histopathology

  • airspace enlargement
  • fragmented alveolar wall due to acinar destruction
• Lung hyperinflation - decrease x-ray attenuation

  • radiolucent lungs
• Highly specific sign for COPD - hyperinflated lung compression
• Emphysema presentation - pink puffer

  • due to severe constant dyspnea or tachypnea ("puffing")

  
• Emphysema - Pink puffer is due to

  • severe constant SOB
  • trapping/decrease recoiling --> poor air exchange
  • body will try to compensate bad ventilation by
  • accessory muscles
  • hyperventilation
  • pursed lip breathing
• ** Emphysema - pink puffer will have pursed lips

  • to try to maintain positive end pressure
  • to preventing airway collapse
• dyspnea in people with emphysema will cause respiratory muscle fatigue due to increase use

  • flat diaphragm also impair respiratory excursions
• why are people with emphysema initially called pink puffer?

  • noncyanotic due to matched V/Q defect
  • no hypoxemia
  • but progressive capillary loss will lead to poor gas exchange leading to hypoxemia and tissue hypoxia
• Emphysema will progress from pink puffer to hypoxia

  1. perfusion drops (↓V/↓↓↓Q)
  2. poor gas exchange
  3. arterial hypoxemia
• Chronic hypoxia in emphysema will eventually lead to cor pulmonale

  1. chronic hypoxia
  2. vasoconstriction
  3. pulmonary HTN
  4. cor pulmonale
• People with emphysema will have hyperinflation

  • diminished breath sounds
  • hyper-resonant percussion
• People with emphysema will also be thin why?

  • inadequate oral intake
  • muscle and fat atrophy
  • high levels of inflammatory cytokines will worsen wasting
• Chronic bronchitis is defined by

  • cough and sputum > 3 month/year period of 2 consecutive years
  • rule out other causes of chronic cough
  • common observed symptoms - productive cough
• Chronic bronchitis - productive cough

  • associated with large airway mucus producing glands hypertrophy
  • sputum production
  • progressive airflow limitation or remodeling
• The most common risk factor for chronic bronchitis is?

  smoking
• Chronic bronchitis can cause hypoxia leading to pulmonary HTN

  • causing cor pulmonale
• Chronic bronchitis histopathology

  • Early
  • mucus hypersecretion in large airways
  • hypertrophy of submucosal glands
  • Late
  • small airway epithelial goblet cell proliferation --> airway obstruction
  • reid index - increase percentage bronchial wall submucosal mucous glands
  • index directly correlates with sputum production
• Chronic bronchitis - presentation - blue bloater

  • cyanotic (blue)
  • V/Q mismatch
  • inadequate blood oxygenation (hypoxemia)
  • most prominent lips and nail beds

  
• Chronic bronchitis - Presentation

  • Volume overload

  1. pulmonary HTN
  2. RV hypertrophy
  3. RV failure
  4. poor LV filling with decrease CO
  5. induction of RAAS
  6. Na and H2O retention
• Chronic bronchitis

  • lots of sputum production
  • produced by goblet cells
  • cough - mucus hypersecretion
  • wheeze - airway obstruction due to turbulent airflow
  • rhonchi - gurgling sound due to mucus hypersecretion in airway
• What is used to diagnosis COPD?

  spirometry
• COPD pulmonary function

  • increase resistance to expiratory airflow due to small airway obstruction
  • increase in lung compliance
  • decrease in lung elasticity