Distinct bronchi visible in the distal two thirds of the lung are abnormal. Bronchiectatic cysts, unlike blebs or bullae, have definable walls. This disease is autosomal recessive and appears most commonly among Caucasians. A mutant gene of chromosome 7 encodes abnormal transport of chloride across epithelial membranes. In the lungs, failure to transport chloride into the airway lumen also decreases transport of sodium and water, leading to excessively viscous secretions.
Respiratory failure is the most common cause of death.
Mucoid impaction causes obstruction and secondary infection, especially by Staphylococcus aureus and Pseudomonas aeruginosa . Resultant fibrosis and cyst formation lead to bronchiectasis with a predilection for the upper lobes. Other complications include atelectasis, bronchitis, emphysema, bronchoceles, pneumothorax and hilar lymphadenopathy. Eventual obliteration of the vascular bed and chronic hypoxia lead to pulmonary arterial hypertension. This patient s respiratory failure eventually led to double lung transplantation.