Introduction: Pneumatosis intestinalis (PI) is a rare complication of transplantation, occurring in up to 5% of lung transplant recipients. PI is a radiographic finding of uncertain significance, and though generally considered benign in transplant recipients, often leads to unnecessary surgical interventions. While a correlation between high doses of immunosuppressants and PI has been suggested, potential risk factors for development of PI have never been examined. Therefore, this study aimed to identify characteristics that may be associated with PI development in lung transplant recipients.

Methods: We retrospectively identified 13 cases of PI occurring post-transplant between 2013-2021. Chart review was conducted to collect variables including demographics and PI clinical characteristics for the patients. Pre-, intra-, and post-operative events for 12 patients were also collected (excluding 1 patient who was transplanted at an outside institution). Descriptive statistics were used for analysis.

Results: The incidence of PI at our institution was 2.3% (12/523). Mean age of patients presenting with PI was 55.2 years, though all but one (20 years old) patients were older than 50. The most common indication for transplant was interstitial lung disease (61.5%). On average PI occurred 417.3 days post-transplant, though cases occurred from 5 days to 4 years post-transplant, with 4 occurring >1 year after transplant. At the time of PI diagnosis, 5 patients were being treated with “pulse dose” steroids for rejection, and eight were on the second-line drug mycophenolic acid instead of mycophenolate mofetil. Three patients underwent negative exploratory laparotomy. Survival at 1 month after PI was 92.3%, with one patient dying 38 days post-retransplantation from primary graft dysfunction complicated by sepsis and multiorgan failure with PI noted on imaging. Recurrences occurred in 2 patients, with one patient having three recurrences up to 5 years post-transplant. Nine of 12 patients had elevated pulmonary artery pressure (PAP) at transplantation, with an average systolic pressure of 55.3.

Conclusion: We characterize the clinical characteristics of pneumatosis intestinalis in 13 lung transplant recipients at our institution. Our findings suggest that PI develops in older patients who had elevated pre-transplant PAP. Furthermore, more than half of the patients with PI were on 2nd-line immunosuppression suggesting predisposition to gastrointestinal issues. Additionally, a significant fraction was on high dose steroids at the time of PI diagnosis, corroborating the findings in the literature of association between aggressive immunosuppression and PI. Similar to published studies, most post-transplant PI cases were benign and surgical intervention was potentially unnecessary. More rigorous studies on risk factors for PI in transplant recipients are warranted.