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
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