Diseases of RESPIRATORY SYSTEM
Chronic Obstructive Pulmonary Diseases Definition: • A group of pulmonary diseases characterized by increased resistance to air flow due to partial or complete obstruction at any level. Types: 1. Chronic bronchitis. 2. Bronchial asthma. 3. Emphysema.
(l) Chronic Bronchitis Definition: • It is persistent productive cough for at least 3 consecutive months in at least 2 consecutive years. • Common in middle-aged men Causes: 1- Cigarette smoking. 2- Atmospheric pollution 3- Chronic inflammation of upper respiratory tract.
Pathology:. N/E: Bronchial mucosa appears thick, opaque and covered by excess mucous. M/P: both bronchi and bronchioles show; 1) Epithelium: - Goblet cell hyperplasia. - Squamous metaplasia and dysplasia. 2) Subepithelial Tissue: - Chronic inflammatory cell infiltrations. - Hyperplasia of mucous glands. - Fibrosis.
Complications: 1- Centrilobular emphysema. 2- Bronchopneumonia. 3- Malignancy: Bronchogenic carcinoma. 4- Pulmonary hypertension and corpulmonale. 5- Heart failure.
(2) Bronchial Asthma Definition: • episodes of reversible bronchospasm resulting from increased responsiveness of the bronchial tree to various types of stimuli. Aetiology and Types: 1. Extrinsic (immunological, atopic, allergic) asthma. 2. Intrinsic asthma (non-immunological, non-allergic).
* N/E: • Small bronchi and bronchioles are spastic (thick and narrow). • Trachea & bronchi are hyperaemic and covered by mucus. • Lung tissue shows emphysematous changes (due to partial bronchial obstruction).
* M/P: • The small bronchi and bronchioles show; 1. Thick basement membrane 2. Narrow lumens, contains mucus plugs which contain whorls of sheded epithelial cells (curschmann spirals), numerous eosinophils and charcot-leyden crystals (esinophil membranes). 3. The subepithelial tissue show; • Hyperplasia of mucous glands. • Hypertrophy of the smooth muscle. • Inflammatory infiltrate formed mainly of eosinophils.
Complications: • Pulmonary hypertension: causing Core pulmonale or heart failure. • Emphysema. • Bacterial infection causing persistent bronchitis, bronchiectasis or pneumonia. • Status asthmaticus: persistent attacks for days or weeks. May lead to respiratory failure.
(3) Emphysema Definition: • Permanent dilatation of air spaces distal to the terminal bronchioles accompanied by damage of their walls.
* Types • Centriacinar (centrilobular) emphysema • Panacinar (panlobular) emphysema