BACKGROUND Pneumothorax may recur during pulmonary Langerhans cell histiocytosis (PLCH) patients' follow-up and its management is not standardised. The factors associated with pneumothorax recurrence are unknown. METHODS In this retrospective study, PLCH patients who experienced a pneumothorax and were followed for at least 6 months after the first episode were eligible. The objectives were to describe the treatment of the initial episode and pneumothorax recurrences during follow-up. We also searched for factors associated with pneumothorax recurrence and evaluated the effect on lung function outcome. Time to recurrence was estimated by the Kaplan Meier method and the cumulative hazard of recurrence handling all recurrent events was estimated. Univariate Cox models and Andersen-Gill counting process were used for statistical analyses. RESULTS Fourty-three patients (median age 26.5 years [interquartile range (IQR), 22.9-35.4]; 26 men, 39 current smokers) were included and followed for median time of 49 months. Chest tube drainage was the main management of the initial pneumothorax, which resolved in 70% of cases. Pneumothorax recurred in 23 (53%) patients, and overall 96 pneumothoraces were observed during the study period. In the subgroup of patients who experienced pneumothorax recurrence, the median number of episodes per patient was 3 [IQR, 2-4]. All but one recurrence occurred within 2 years after the first episode. Thoracic surgery neither delayed the time of occurrence of the first ipsilateral recurrence nor reduced the overall number of recurrences during the study period, although the rate of recurrence was lower after thoracotomy than following video-assisted thoracic surgery (p = 0.03). At the time of the first pneumothorax, the presence of air trapping on lung function testing was associated with increased risk of recurrence (hazard ratio = 5.08; 95% confidence interval [1.18, 21.8]; p = 0.03). Pneumothorax recurrence did not predict subsequent lung function decline (p = 0.058). CONCLUSIONS Our results show that pneumothorax recurrences occur during an "active" phase of PLCH. In this observational study, the time of occurrence of the first ipsilateral recurrence and the overall number of pneumothorax recurrences were similar after conservative and thoracic surgical treatments. Further studies are needed to determine the best management to reduce the risk of pneumothorax recurrence in PLCH patients.

中文翻译：

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成年朗格汉斯细胞组织细胞增生症患者气胸的治疗和转归。

背景技术气胸可能会在肺部Langerhans细胞组织细胞增生症（PLCH）患者的随访期间复发，其管理尚不规范。与气胸复发相关的因素尚不清楚。方法在这项回顾性研究中，患有气胸并在首发后至少随访6个月的PLCH患者是合格的。目的是描述随访期间初始发作和气胸复发的治疗方法。我们还搜索了与气胸复发相关的因素，并评估了对肺功能预后的影响。通过Kaplan Meier方法估算了复发时间，并估算了处理所有复发事件的复发累积危害。使用单变量Cox模型和Andersen-Gill计数过程进行统计分析。结果纳入患者43例（中位年龄26.5岁[四分位间距（IQR），22.9-35.4]； 26名男性，现时吸烟者39名），随访时间中位数为49个月。胸腔引流是最初气胸的主要治疗方法，在70％的病例中这种情况得到了解决。气胸复发23例（53％），在研究期间共观察到96例气胸。在经历了气胸复发的患者亚组中，每位患者的中位发作次数为3 [IQR，2-4]。除一次复发外，所有复发均发生在首发后2年内。在研究期间，胸外科手术既不会延迟首次同侧复发的发生时间，也不会减少总的复发次数，尽管开胸手术后的复发率低于电视胸腔镜手术后的复发率（p = 0.03）。在第一次气胸时，肺功能测试中存在空气滞留与复发风险增加相关（危险比= 5.08； 95％置信区间[1.18，21.8]； p = 0.03）。气胸复发不能预测随后的肺功能下降（p = 0.058）。结论我们的结果表明气胸复发发生在PLCH的“活跃”阶段。在这项观察性研究中，经过保守和胸外科手术治疗后，首次发生同侧复发的时间和气胸复发的总数相似。需要进一步的研究来确定最佳的治疗方法，以减少PLCH患者发生气胸复发的风险。