Cystic fibrosis
Cystic fibrosis is the most common life-threatening autosomal recessive disease in the United States and Europe. It is a genetic disorder that affects the lungs, but also the pancreas, liver, kidneys, and intestine. It is caused by mutations in the CFTR protein, a chloride channel expressed in epithelial cells. Lung disease results from clogging of the airways due to mucus build-up, decreased mucociliary clearance, and resulting inflammation. In later stages, changes to the structure of the lung, such as bronchiectasis, occur. Around 5 to 10% of all patients with cystic fibrosis develop bronchiectasis. Airway obstruction
An airway obstruction can be caused by either an intraluminal mass such as a tumor or a foreign body. The presence of an airway obstruction leads to a cycle of inflammation. It is important to identify the presence of an obstruction because surgical resection is often curative if obstruction is the cause. In adults, foreign body aspiration is often associated with an altered state of consciousness. The foreign body is often unchewed food, or part of a tooth or crown. Bronchiectasis that results from foreign body aspiration generally occurs in the right lung in the lower lobe or posterior segments of the upper lobe. Lung infections
A range of bacterial, mycobacterial, and viral lung infections are associated with the development of bronchiectasis. Bacterial infections commonly associated with bronchiectasis include P. aeruginosa, H. influenzae, and S. pneumoniae. Gram-negative bacteria are more commonly implicated than gram-positive bacteria.
Exacerbations in bronchiectasis present as a worsening of cough, increasing sputum volume or thickened consistency lasting at least 48 hours, worsening shortness of breath (breathlessness), worsening exercise intolerance, increased fatigue or malaise and the development of hemoptysis.People often report frequent bouts of "bronchitis" requiring therapy with repeated courses of antibiotics. People with bronchiectasis may have bad breath from active infection. On examination, crepitations and expiratory rhonchi may be heard with auscultation. Nail clubbing is a rare symptom.The complications of bronchiectasis include serious health conditions, such as respiratory failure and atelectasis:
collapse or closure of a lung. Respiratory failure occurs when not enough oxygen passes from the lungs into the blood. Atelectasis occur when one or more segments of the lungs collapse or do not inflate properly. Other pulmonary complications include lung abscess and empyema. Cardiovascular complications include cor pulmonale, in which there is enlargement and failure of the right side of the heart as a result of disease of the lungs. Causes
There are many causes that can induce or contribute to the development of bronchiectasis. The frequency of these different causes varies with geographic location. Cystic fibrosis is identified as a cause in up to half of cases. Bronchiectasis without CF is known as non-CF bronchiectasis. Historically, about half of all case of non-CF bronchiectasis were found to be idiopathic, or without a known cause. However, more recent studies with a more thorough diagnostic work-up have found an etiology in 60 to 90% of patients.