Chronic
Bronchitis
Epidemiology:
- Smokers
- Denizens of
smog-laden cities
- Middle aged men
often
- Irritants:
- Smoke
- Grain
- Cotton
- Silica dust
Common sites:
Gross features:
- hyperemia,
swelling, and edema of the mucous membranes’
- excessive mucinous to mucopurulent
secretions on epithelial surfaces
- heavy casts of
secretions and pus in bronchi and bronchioles sometimes
Histologic features:
- hypertrophy of submucosal glands in trachea and bronchi (early)
- Reid index:
ratio of thickness of mucous gland layer to the thickness of the wall
between the epithelium and cartilage
- marked increase in
goblet cells of small airways: small bronchi and bronchioles (goblet cell
metaplasia)
- lymphocytic predominant chronic inflammation of
the airways
- squamous metaplasia
- squamous dysplasia
- fibrosis causing narrowing
of bronchioles
- bronchiolitis obliterans:
most severe extreme – obliteration of bronchiole lumen due to fibrosis
Immunophenotype:
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Marker:
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Sensitivity:
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Specificity:
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Molecular features:
Other features:
- complications:
- COPD
- Cor pulmonale
- Atypical metaplasia and dysplasia
of respiratory epithelium
- Clinical definition:
- Chronic cough
with sputum production for 3 months in at least 2 consecutive years
- If hyperreactive airways are present, it is called
chronic asthmatic bronchitis
- Infections provoke
exacerbations and help maintain the disease
- Hypersecretion of mucous is earliest feature
- Caused by
proteases released by neutrophils and matrix metalloproteinases
References: