Obstructive Airway Diseases Flashcards
What are the 2 types of COPD
Emphysema and chronic bronchitis
What 2 major groups do obstructive airway diseases fall into
Localised and diffuse
What is chronic bronchitis
It is the long term inflammation of the bronchi
Aetiology of chronic bronchitis
Cigarette smoking
Air pollutants - such as sulfur dioxide, nitrogen dioxide
Toxic industrial inhalants - occupational dust exposure
Respiratory tract infection - may initiate and promote chronic bronchitis
Clinical features of chronic bronchitis
• Usually affects middle-aged men who
are heavy smokers.
• Early symptoms: Persistent
productive cough (sputum) for many
years.
• Later stage: – Dyspnea on exertion.
What is the Pathogenesis of chronic bronchitis
Irritation by inhaled air pollutants
This irritation causes infiltration of T lymphocytes, macrophages and neutrophils
Hypersecretion of mucus
Hyperplasia/hypertrophy of submucosal glands in large airways - develops in response to inhaled environmental irritants and proteases released by neutrophils
Increase of goblet cells in small airways also leads to mucus plugging bronchial lumen which causes inflammation and fibrosis of bronchial wall leading to narrowing of bronchioles
What are the microscopic appearances of chronic bronchitis
Hyperplasia and hypertrophy of mucus secreting glands in the submucosa
Chronic inflammation
Increase of goblet cells
Marked narrowing of bronchioles: It is due to – Excess mucus in the airways. – Thickening of the bronchial wall due to hyperplasia of mucus glands, edema, inflammation, and fibrosis. – In severe cases, there may be obliteration of lumen due to fibrosis (bronchiolitis obliterans).
What is emphysema
Abnormal irreversible dilatation of airspaces located distal to the terminal bronchioles caused by destruction of their wall.
What is the pathogenesis of emphysema
Normal vs Emphysema alveoli
Normal alveoli can recoil back whereas emphysema effected cannot so air can get trapped
What is the gross appearance of emphysema
Usually affects upper two thirds
Bullae (little balloons) are found in irregular and distal acinar emphysema
Advanced emphysema produces voluminous lungs (can see 12 ribs on x ray instead of 6)
What are the types of emphysema
What does acinus mean
Sac like structure
Normal vs centriacinar emphysema
Involvement of central part of acinus
Seen in smokers
Usually more severe in upper lobes
Most common type seen clinically
Normal vs panacinar emphysema
Involvement of entire acinus
Seen with α1-AT (alpha 1 antitrypsin - which affects protease/antiprotease imbalance resulting in alveolar wall destruction)
Occurs more severely at base of lung as perfusion is greatest here so more neutrophils
What does emphysema look like under microscope
Abnormally large alveoli
Destruction of alveolar walls
Bullae
Inflammation in small airways
What is bronchial asthma
Disorder of bronchial tree due to reversible bronchoconstriction in response to a hypersensitity 1 reaction
What is pathogenesis of bronchial asthma
The allergen is taken by antigen presenting cells (macrophage/dendritic cell) and elicits a hypersensitivity-dominated response. This promotes production of IgE by B cells.
Bronchial asthma gross appearance
Airways (bronchi and bronchioles) are occluded by plugs of thick,
tenacious mucus.
In patients who die due to status asthmaticus (severe asthma unresponsive to repeated courses of beta-agonist therapy), the lungs are greatly distended due to overinflation, and shows small areas of atelectasis (collapse).
What conditions are curschmann spirals Charcot-Leyden crystals and creola bodies seen in
asthma
