Proximal Bronchiectasis is feature of?

Ans. a (Allergic bronchopulmonary aspergillosis) (Ref. Harrison's Medicine, 18thCh. 204)Bronchiectasis accompanying ABPA often involves proximal airways and is associated with mucoid impaction.Other features on high-resolution CT scanning can suggest a specific etiology of the bronchiectasis. For example, bronchiectasis of relatively proximal airways suggests ABPA, whereas the presence of multiple small pulmonary nodules (nodular bronchiectasis) suggests infection with M. avium complex.BRONCHIECTASISEtiologies of Bronchiectasis- Mycobacterial- Viral (Swyer-James syndrome)- Fungal (including ABPA)- Dyskinetic cilia syndromes (Kartagener's)- Cystic fibrosis- Alphal-antitrypsin deficiency- Mounier-Kuhn's syndrome- Williams-Campbell syndrome- Bronchopulmonary sequestration- AIDS- Acquired hypogammaglobulinemia- Selective or pangammaglobulinemia- Postobstructive (neoplasm, foreign body, stricture)- Chronic rejection (obliterative bronchiolitis)- Graft-versus-host disease- Aspiration- Inhalation of toxic gases- Collagen vascular diseases- Asthma- Yellow-nail syndrome- Sarcoidosis High-resolution CT (HRCT) is accepted accurate noninvasive means of diagnosing bronchiectasis. Signs described on CT include: tram-track sign, signet ring sign, string of pearls sign, and cluster of grapes sign. When a dilated bronchus is oriented perpendicularly to the plane of the section it is recognized in cross-section as a ring structure, with an internal diameter larger than that of its accompanying pulmonary artery branch. Termed the signet ring sign, the wall of the dilated bronchus represents the band of the ring, whereas the signet is the soft-tissue density produced by the artery. This is diagnostic sign.A wide spectrum of abnormalities may be identified at HRCT in patients with airway disease, including various distinctive patterns of bronchiectasis in specific clinical settings, such as ABPA, MAC infection, AIDS, and cystic fibrosis (CF). The predominant HRCT finding in CF is bronchiectasis, which is typically panlobar. Proximal and parahilar bronchiectasis are identified in all of these cases; in about a third of cases it is limited to these areas, a pattern termed CENTRAL OR PROXIMAL BRONCHIECTASIS, as seen in ABPA.