COPD & Bronchiectasis (12/7/16) - Hussain

Question 1

What is bronchiectasis?

Answer 1

Permanent abnormal dilatation of bronchioles and bronchi → loss of airway tone results in air trapping

Question 2

What is bronchiectasis due to?

Causes (5)?

Answer 2

Due to necrotizing inflammation with damage to airway walls. Causes include:

• Cystic fibrosis (thick secretions → mucus plug → inflammation)
• Kartagener syndrome → inherited defect of dynein arm (necessary for ciliary movement)
  
  • Associated with sinusitis, infertility (poor motility of sperm), situs inversus (position of major organs reversed)
  • Don’t have cilia to pump mucus out of lungs
• Tumor of foreign body → inc. risk of infection
• Necrotizing infection
• Allergic bronchopulmonary aspergillosis → hypersensitivity rxn to Aspergillus → chronic inflammatory damage
  
  • Usually seen in individuals w asthma or CF

Question 3

Clinical features

Answer 3

• Cough (b/c of mucus trapping)
• Dyspnea
• Foul-smelling sputum (loaded w inflammatory junk)

Question 4

Complications

Answer 4

• Hypoxemia w/ cor pulmonale and secondary (AA) amyloidosis
  
  • Deposition of misfolded protein
  • Chronic inflammation end product SAA converted to AA and deposited as amyloid

Question 5

Types of COPD

Answer 5

• Chronic bronchitis
• Emphysema
• Asthma
• Bronchiectasis

Question 6

Chronic Bronchitis

Characterization

Answer 6

• Chronic productive cough - lasts at least 3 mo. over 2+ years
• Highly associated with smoking
• Diffuse process
• Characterized by hypertrophy of bronchial mucinous glands
  
  • ​Smoking inc. production/thickness of mucus glands relative to bronchial wall thickness

Question 7

Chronic Bronchitis

Clinical features

Answer 7

• Productive cough due to excessive mucus production
  
  • Difficulty clearing secretions b/c of poor ciliary function
• Cyanosis (“blue bloaters”)
  
  • Mucus plugs trap CO2
    
    • Inc PaCO2 and dec. PaO2
• Inc. risk of infection and cor pulmonale

Trapped <——- mucus in lumen ———-> cough

Question 8

What usually exacerbates chronic bronchitis?

Answer 8

Viral infections

Question 9

Emphysema

Characterization

Answer 9

• Destruction of alveolar air sacs
  
  • Loss of elastic recoil and collapse of airways during exhalation
  • RESULT: obstruction and air trapping

Question 10

Emphysema

Cause

Answer 10

Imbalance of proteases and antiproteases

• Inflammation in lung normally leads to release of proteases by neutrophils and macrophages
• alpha1-antitrypsin (A1AT) neutralizes proteases
• Excessive inflammation OR lack of A1AT → destruction of alveolar air sacs

Question 11

Most common cause of emphysema?

Answer 11

Smoking

Pollutants in smoke → excessive inflammation and protease-mediated damage

Result: centriacinar emphysema most severe in upper lobes

Question 12

A1AT deficiency

Answer 12

• Rare cause of emphysema
  
  • Lack of antiprotease leaves air sacs vulnerable to protease-mediated damage
• Results in panacinar emphysema most severe in LOWER LOBES
• Liver cirrhosis may also be present
  
  • A1AT deficiency due to misfolding of mutated protein
  • Mutant A1AT accumulates in ER of hepatocytes → liver damage
  • Biopsy = pink, PAS-positive globules in hepatocytes

Question 13

Emphysema

Clinical features

Answer 13

• Dyspnea and cough w MINIMUAL SPUTUM (NOT chronic bronchitis)
• Prolonged expiration w/ pursed lips (“pink puffer”)
  
  • ​Back pressure from pursed lips will force walls open
• Weight loss (all their calories are going into breathing)
• Inc. A-P diameter of chest (‘barrel chest’)
• Late complications:
  
  • Hypoxemia (due to destruction of capilllaries in alveolar sac)
    
    • Late b/ body will gravitate towards good lung units until there is no more
    • Inc ventilation of poorly perfused lung units (high V/Q ratio)
  • cor pulmonale