Pathological and Clinical Aspects of COPD Flashcards Preview

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Flashcards in Pathological and Clinical Aspects of COPD Deck (12):
1

What is the definition of COPD?

- Progressive airflow obstruction that is not fully reversible and does not change markedly over several months

2

What are the common causes of COPD?

- Smoking

- Alpha 1 antitrypsin deficiency

3

What is the pathogenesis of COPD?

- Loss of elasticity and alveolar attachements due to emphysema (airways collapse on expiration causing air trapping, hyperinflation, increased work of breathing and SOB)

- Goblet cell metaplasia with mucus plyggung of lumen

- Inflammation of the airway wall

- Thickening of bronchiolar wall (smooth muscle hypertrophy and peribronchial fibrosis)

4

What is chronic bronchitis?

- Production of sputum on most days for at least 2 months in at least 2 years

- Larger airways >4mm in diameter

- Develop airway inflammation (predominantly neutrophilic with CD8 cytotoxic lymphocytes and some eosinophils which leads to scarring and thickening of the airways)

- Inflammatory mediators include TNF, IL-8, neutrophil elastase, proteinase 3, cathespin G, elastase and MMPs from macrophages and ROS

- Squamous metaplasia and as tissue is destroyed you lose the interstitial support of the tissue around the bronchioles making them more collapsible

5

What is emphysema?

- Abnormal, permanent enlargement of the airspaces distal to the terminal bronchioles

- Four general types but centri-acinar (damage around respiratory bronchioles) and pan-acinar (uniformly enlarged from the level of terminal bronchiole distally) are most important

6

What are the stages of COPD?

- 1) Mild - FEV1 80%

- 2) Moderate - FEV1 50-79%

- 3) Severe - FEV1 30-49%

- 4) Very severe - FEV1 <30% or <50% with respiratory failure

7

What does type 1 respiratory failure look like?

- Pink puffer

- High respiratory drive

- ↓PaO2, ↓PaCO2

- Signs and symptoms include desaturation on exercise, pursed lip breathing, use of accessory muscles, wheeze, indrawing of intercostals and tachypnoea

8

What does type 2 respiratory failure look like?

- Low respiratory drive

- Type 2 respiratory failure

- ↓PaO2, ↑PaCO2

- Signs and symptoms include cyanosis, warm peripheries, bounding pulse, flapping tremor, confusion, drowsiness, right heart failure, oedema and raised JVP

9

What are the processes in asthmatic airway inflammation?

- CD4+ lymphocytes

- T lymphocytes

- Eosinophils

10

What are the processes involved in COPD airway inflammation?

- CD8+

- T lymphocytes

- Macrophages

- Neutrophils

11

Why does cigarette smoking cause COPD?

- Cigarette smoking leads to reduced cilial motility, neutrophilic inflammation, mucus hypertrophy and Goblet cells, increased protease activity against anti-protease inhibition leading to more damage to tissues in the lungs (i.e. α1 antitrypsin is one of the main anti-proteases) and oxidative stress. Furthermore it can lead to squamous metaplasia.

12

How is COPD treated?

- Inhaled bronchodilators (salbutamol, salmeterol)

- Inhaled corticosteroids (budenoside, fluticasone)

- Oral theophyllines

- Mucolytics (carbocysteine)

- Nebulised therapy