Traumatic pulmonary pseudocysts after blunt chest trauma: Prevalence, mechanisms of injury, and computed tomography findings.

Background: Traumatic pulmonary pseudocyst (TPP) is a rare complication of blunt chest trauma and closely related with severe injury. However, it has been poorly documented. We present a retrospective review of TPP cases treated at our hospital.

Methods: The medical records and chest computed tomography scans of patients with TPP treated from January 2010 to December 2013 were retrospectively studied.

Results: A total of 978 patients underwent chest computed tomography for blunt chest trauma during the study period, and 81 (8.3%) had a total of 150 TPPs. The most common mechanism of injury was being struck by a motorized vehicle (n = 25, 30.9%). The mean (SD) Injury Severity Score (ISS) of the 81 patients was 33.2 (11.4). The prevalence of TPP was higher in younger patients (p = 0.011), but the total number of fractured ribs was significantly lower (p = 0.001). In a subgroup analysis performed according to pseudocyst location, the intraparenchymal group had more severe injuries than the subpleural group (ISS, 23.3 vs. 32.4, p < 0.001; chest Abbreviated Injury Scale [AIS] score, 3.4 vs. 4.0, p < 0.001; number of associated injuries, 2.9 vs. 4.0, p = 0.001). By multivariate analysis, ISS, age, and number of associated injuries were significantly different in these two groups (p = 0.038, p = 0.006, and p = 0.045, respectively).

Conclusion: The prevalence of TPP among cases of blunt chest trauma was 8.3% and was higher in those struck by a vehicle and younger patients. Intraparenchymal pseudocyst was found to be related to more severe injuries. TPP was a self-limiting condition that does not require specific treatment.

Level Of Evidence: Prognostic/epidemiologic study, level IV.