Asthma and Airways Centre, University Health Network, University of Toronto, Toronto, ON, Canada.
Chest. 2011 Jan;139(1):23-7. doi: 10.1378/chest.10-0186. Epub 2010 Sep 9.
Symptomatic disease due to nontuberculous mycobacteria (NTM) is known to occur commonly in the presence of structural lung disease, but is not described in association with asthma.
This was a case-control study nested in a cohort. We identified 22 patients with difficult asthma referred to a tertiary academic referral center and subsequently found to have infection with NTM. We matched each case with two control subjects (next two consecutive patients referred for asthma management).
It took on average 2.1 years from the onset of new or worsening symptoms to NTM diagnosis. The most common symptoms were worsening cough (77%), sputum production (40.9%), and frequent exacerbations (31.8%). Mycobacterium avium complex accounted for 63.6% of the infections, Mycobacterium xenopi the balance. Case subjects were older (59.8 ± 8.9 vs 42.6 ± 18 years; P < .001) and had more severe airflow obstruction (FEV(1), 57% [40%-74%] vs 89.5% [80%-98%]; P < .001). There was no difference between case and control subjects in the proportion using inhaled corticosteroids (ICS) or the average daily dose at the time of presentation, but case subjects had used ICS for a longer period (17 [6.2-20] vs 4 [0.75-6.0] years; P=.002). Six subjects with NTM were being treated with daily oral steroids, whereas none of the control subjects was. Of the 22 cases, 10 were treated with antibiotics for NTM, seven demonstrating clinical improvement or resolution of the presenting symptoms.
NTM infection can be associated with asthma and should be considered in difficult-to-treat disease, especially in older individuals with more severe airflow obstruction and greater exposure to inhaled or systemic corticosteroids.
非结核分枝杆菌（NTM）引起的症状性疾病通常发生在结构性肺病存在的情况下，但与哮喘无关。
这是一项嵌套在队列中的病例对照研究。我们确定了 22 名因难治性哮喘而被转诊到三级学术转诊中心的患者，随后发现他们感染了 NTM。我们为每个病例匹配了两名对照患者（下一个连续两名因哮喘管理而就诊的患者）。
从新出现或恶化的症状到 NTM 诊断的平均时间为 2.1 年。最常见的症状是咳嗽加重（77%）、咳痰（40.9%）和频繁恶化（31.8%）。分枝杆菌复合群占感染的 63.6%，分枝杆菌 xenopi 占其余部分。病例组年龄较大（59.8 ± 8.9 岁 vs 42.6 ± 18 岁；P <.001），气流阻塞更严重（FEV1，57%[40%-74%] vs 89.5%[80%-98%]；P <.001）。病例组和对照组在使用吸入性皮质类固醇（ICS）的比例或就诊时的平均日剂量方面没有差异，但病例组使用 ICS 的时间更长（17 [6.2-20] 年 vs 4 [0.75-6.0] 年；P=.002）。6 名 NTM 患者正在接受每日口服皮质类固醇治疗，而对照组中没有。在 22 例病例中，有 10 例因 NTM 接受了抗生素治疗，其中 7 例临床表现改善或出现的症状得到缓解。
NTM 感染可与哮喘相关，在治疗困难的疾病中应考虑到这一点，特别是在有更严重气流阻塞和更多吸入或全身皮质类固醇暴露的老年患者中。
