Active Tuberculous Endobronchitis: Computed Tomography Findings and Implications
THT Sung, JSF Shum, WH Kwan
Hong Kong J Radiol 2013;16:117-22
DOI: 10.12809/hkjr1312149
Objective: To describe the pattern of bronchostenosis revealed by computed tomography and virtual bronchoscopy in patients with active tuberculous endobronchitis and associated pulmonary manifestations.
Methods:This retrospective study was conducted in Hong Kong, which is an endemic region for tuberculosis, where tuberculous endobronchitis remains a noteworthy clinical entity, with reported frequency of 10 to 40% in patients with active pulmonary tuberculosis. Medical records of a series of 18 patients with active endobronchial tuberculosis (without acquired immunodeficiency syndrome), having acid-fast bacilli in sputum smears, underwent computed tomography and virtual bronchoscopy in two regional hospitals between January 2007 and October 2009 were reviewed. The location, morphology, length, and percentage of luminal bronchostenotic narrowing were evaluated by such imaging and compared with fibre-optic bronchoscopy findings. Associated parenchymal manifestations, namely tree-in-bud nodules, cavitary lesions, segmental atelectasis and enlarged mediastinal lymph nodes, were assessed.
Results:Involvement of tuberculous endobronchitis at a single major lobar bronchus with contiguous spread along ipsilateral bronchial tree was observed in most patients (n = 16, 89%). A mural cause of bronchostenosis remained the most frequent finding (n = 12, 67%), with irregular circumferential thickening predominating (n = 8, 44%). Regarding associated parenchymal manifestations, tree-in-bud nodules occurred in all patients (n = 18, 100%); cavitary lesions (n = 9, 50%) and segmental atelectasis (n = 7, 39%) were less frequent. Mediastinal lymph node enlargement was a rare finding (n = 3, 17%). Fibre-optic bronchoscopy performed during the same admission showed confirmatory results in all available cases (n = 14).
Conclusion:Centripetal spread of tuberculous endobronchitis from distal small airways to proximal central airway was observed in the majority of our patients. This could correlate with probable pathogenic mechanisms including the submucosal lymphatic spread of tuberculous bacilli and the implantation of bacilli by infected sputum along the bronchial tree. Relative left-sided predominance of bronchial involvement was observed, possibly related to intrinsic anatomical difference in lymphatic drainage between left- and right-sided bronchi. Irregular circumferential and eccentric mural thickening was the most common morphological pattern of bronchostenosis with mural thickening. Mediastinal lymph node enlargement was rare.
中文摘要
支氣管內膜結核活躍期：電腦斷層掃描結果和啟示
宋咸東、岑承輝、關永豪
目的：描述支氣管內膜結核活躍期的病人電腦斷層掃描和虛擬支氣管鏡檢查顯示的支氣管狹窄的模 式，及相應的肺部變化。
方法：回顧研究於香港完成。結核是香港的地方病，其肺結核患者中有一至四成為支氣管結核，所 以此病仍然是值得關注的臨床疾病。本文回顧香港兩間分區醫院於2007年1月至2009年10月期間收治 的18名支氣管內膜結核活躍期（並無愛滋病）病人的病歷，病人的檢查包括痰塗片抗酸桿菌測試、 電腦斷層掃描和虛擬支氣管鏡。評價支氣管腔狹窄的位置、形態、長度及百分比；並與纖維支氣管 鏡顯示結果比較。同時評估相應的肺實質表現：樹芽徵、空洞、肺段不張及縱隔淋巴結腫大。
結果：大多數患者（n = 16，89%）的支氣管結核病灶累及單支葉主支氣管，並沿同側支氣管樹播 散。最常見的仍是管壁因素引致的支氣管狹窄（n = 12，67%），同時以管壁不規則環形增厚為主 （n = 8，44%）。相應的肺實質表現為：所有患者均有樹芽徵（n = 18，100%）；空洞性病變（n = 9，50%）和肺段不張（n = 7，39%）相對較少。縱隔淋巴結腫大更為罕見（n = 3，17%）。所有該 次入院的纖維支氣管鏡檢查（n = 14）均證實相應的影像表現。
結論：本研究大部份的病人均存在病灶從遠端細支氣管向近端中央型支氣管播散的「向心傳播」現 象。這與可能的致病機制有關，包括結核桿菌沿黏膜下淋巴道播散，以及含菌痰液中的細菌沿支氣 管樹種植播散。相對來說，以左肺支氣管受累為主，這可能與左右支氣管之間淋巴引流的差別有 關。管壁不規則環形增厚和偏心型增厚是最常見的支氣管狹窄形態。縱隔淋巴結腫大則屬罕見。