Bronchiectasis

Bronchiectasis

1. 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

2. 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

3. 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.

4. 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

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