Primary spontaneous pneumomediastinum: 237 cases in a single-center experience over a 10-year period and assessment of factors related with recurrence.

Objective: To evaluate the precipitating factors and symptoms of primary spontaneous pneumomediastinum (PSPM) and to assess the factors related with recurrent spontaneous pneumomediastinum (RSPM).

Methods: From 2010 to 2021, 237 PSPM patients were included in this retrospective study. Clinical information including in-hospital periods, morbidity, mortality, presenting symptoms, precipitating events, smoking, and asthma history was obtained. The patients with smoking history were subdivided into "ex-smoker" or "current smoker". The severity of asthma was categorized into "mild intermittent", "mild persistent", "moderate persistent", or "severe persistent". During follow-up, patients with RSPM were classified into "recurrence" group and the others were into "no recurrence" group. Multivariate regression analysis was used to elucidate the associated factors with RSPM.

Results: The mean age of study patients (men: women = 222: 15) was 23.4 years and mean period of hospital stay was 7.5 days. There was no mortality and morbidity. Most frequent symptom and precipitating factor were acute chest pain (n = 211, 89.0%) and cough (n = 72, 30.4%), respectively. RSPM occurred in 11 patients (4.6%). The proportion of patients with smoking (72.8% vs. 37.1%, p = 0.010) or asthma (81.8% vs. 39.8%, p<0.001) was significantly higher in "recurrence" group than "no recurrence" group. On multivariate analysis, asthma was the only factor associated with RSPM (mild intermittent/persistent, OR = 7.092, p = 0.047; moderate persistent, OR = 8.000, p = 0.011).

Conclusion: PSPM is a benign disease with no morbidity and mortality. Asthma may be the associated factor with RSPM; thus, despite the low rate of recurrence, patients with asthma should be informed about the chance of RSPM.