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Bronchiectasis
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Bronchiectasis
Permanent DILATION of the bronchi and bronchioles causing repeated episodes of airway infection and inflammation << Due to destruction of cartilage and elastic tissue by chronic necrotizing infections
Causes
- Cystic fibrosis
- Autosomal recessive disease
- Pathogenesis
- (1) Most common mutation is a three-nucleotide deletion on chromosome 7 that normally codes for phenylalanine (70% of cases).
- (2) Mutation causes defective protein folding in the cystic fibrosis transmembrane conductance regulator (CFTR).
- (3) Defective CFTR is degraded in the Golgi apparatus.
- (4) Loss of CFTR causes decreased Cl– reabsorption in the sweat glands
- Effect of loss of CFTR in other secretions:
- (a) Increased Na+ and water reabsorption from luminal secretions
- (b) Decreased Cl– secretion out of epithelial cells into luminal secretions
- (c) Net effect of these electrolyte alterations is dehydration of body secretions due to lack of NaCl.
- Infections
- (a) TB is the most common cause worldwide.
- (b) Mycobacterium avium-intracellulare (typically involves the right middle lobe and lingula), adenovirus, Staphylococcus aureus, Haemophilus influenzae
- Bronchial Obstruction
- Primary ciliary dyskinesia
- (a) Dynein arm in cilia is absent.
- (b) Dynein arm contains ATPase (adenosine triphosphatase) for movement of the cilia.
- Allergic bronchopulmonary aspergillosis
- Cystic fibrosis
Gross Findings
- a. Most commonly occurs in the lower lobes
- b. Dilated bronchi and bronchioles are filled with pus
- (1) Dilated airways extend to the lung periphery.
- (2) Dilations are tube-like and/or saccular.
Clinical Findings
- a. Cough productive of copious sputum (often cupfuls)
- b. Hemoptysis that is sometimes massive
- c. Digital clubbing
- d. Cor pulmonale
- Chest cardiograph & CT scan Findings
- Crowded bronchial markings extend to the lung periphery