Page 377 - Concise Pathology for Exam Preparation ( PDFDrive )

362 SECTION II Diseases of Organ Systems

Cigarette smoking predisposes to infection by
• Interfering with ciliary action of respiratory epithelium and function of alveolar macrophages
• Causing direct damage to airway epithelium
• Leading to hypertrophy and hyperplasia of mucous glands
• Inhibiting ability of bronchial and alveolar leukocytes to clear bacteria
Gross Morphology
• Hyperaemia, swelling and oedema of airways
• Excessive mucinous to mucopurulent secretions in the bronchi and bronchioles
Microscopy (Fig. 13.4)
• Chronic (predominantly lymphocytic) inflammation of airways
• Enlargement of mucous-secreting glands of trachea and bronchi
• Increase in number of goblet cells and mucous glands in airways
• Increase in Reid index (ratio of thickness of the mucous gland layer to the thickness of
the wall between the epithelium and the cartilage (normal 0.4))
• Squamous metaplasia and dysplasia
• Obliteration of lumina of bronchioles due to fibrosis (bronchiolitis obliterans)
Histopathological changes in small airways in young smokers include
• Goblet cell metaplasia with mucous plugging
• Clustering of pigmented alveolar macrophages and infiltration by inflammatory cells
• Fibrosis of bronchiolar wall
Clinical Features
• Persistent cough with production of sputum
• Later stages, hypercapnia, hypoxaemia and mild cyanosis
• Death is due to severe infection or cor pulmonale and cardiac failure

Bronchial Asthma

Definition
Asthma is a chronic inflammatory disorder of the airways that causes recurrent episodes
of wheezing, breathlessness, chest discomfort and cough particularly at night and/early
Ciliated columnar cells

Goblet cells
Plasma cells
Lymphocytes

Smooth muscle

Hyperplastic
mucous glands

Cartilage

FIGURE 13.4. Histopathology of chronic bronchitis showing chronic inflammation of airways,
enlargement of mucous-secreting glands of trachea and bronchi, increase in number of goblet
cells and mucous glands in airways and increase in Reid index.

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