Most common cause of diffuse bronchiectasis is
(C) Cystic Fibrosis # DIFFUSE BRONCHIECTASIS develops most often in patients with genetic, immunologic, or anatomic defects that affect the airways. In developed countries, many cases appear initially to be idiopathic, probably partly because onset is so slow that the triggering problem cannot be identified by the time bronchiectasis is recognized.> With newer, improved genetic and immunologic testing, an increasing number of reports describe finding an etiology in these idiopathic cases after careful, systematic evaluation.> Cystic Fibrosis (CF) is the most common identified cause, and previously undiagnosed CF may account for up to 20% of idiopathic cases. Even heterozygous patients, who typically have no clinical manifestations of CF, may have an increased risk of bronchiectasis.> Immunodeficiencies such as common variable immunodeficiency (CVID) may also lead to diffuse disease, as may rare abnormalities in airway structure. Undernutrition and HIV infection also appear to increase risk.> Congenital defects in mucociliary clearance such as primary ciliary dyskinesia (PCD) syndromes may also be a cause, possibly also explaining some idiopathic cases.> Diffuse bronchiectasis sometimes complicates common autoimmune disorders, such as RAor Sjogren syndrome.> Allergic bronchopulmonary aspergillosis, a hypersensitivity reaction to Aspergillus spp. (Allergic Bronchopulmonary Aspergillosis (ABPA)) that occurs most commonly in people with asthma, but sometimes in patients with CF, can cause or contribute to bronchiectasis.> In developing countries, most cases are probably caused by TB, particularly in patients with impaired immune function due to undernutrition and HIV infection.> Focal bronchiectasis typically develops as a result of untreated pneumonia or obstruction (eg, due to foreign bodies, tumors, postsurgical changes, lymphadenopathy). Mycobacteria (tuberculous or nontuberculous) can both cause focal bronchiectasis and colonize the lungs of patients with bronchiectasis due to other disorders.
Untreated pneumonia
Obstruction due to foreign bodies
Cystic Fibrosis
Tuberculous infection
Miscellaneous