Chylothorax can be a presenting symptom of complex lymphatic anomaly in children and is associated with significant respiratory morbidity. Historically, the traditional pharmacological treatment has been octreotide. There are several treatments that have been utilized in the past few years including sirolimus; however, data regarding their efficacy and outcomes is limited. Furthermore, sirolimus has proven efficacy in complex vascular malformations, and hence, its utility/efficacy in infantile primary chylous effusions warrants further investigation.

In this retrospective study at Texas Children's Hospital, data were extracted for all infants with chylothorax who were treated with sirolimus between 2009 and 2020. Details regarding underlying diagnosis, comorbidities, and number of days from sirolimus initiation to resolution of effusion were collected.

Initially a total of 12 infants were identified. Among them, seven patients had complete data and were included in the study. Reasons for chylous effusions include presumed complex lymphatic anomaly, generalized lymphatic anomaly, and complex congenital lymphatic anomaly. The mean duration of sirolimus treatment needed for chest tube removal was 16 days, with a median of 19 days and range of 7–22 days. No patients had progression of effusions while on sirolimus.

With close monitoring, sirolimus appears to be an effective therapy for pediatric lymphatic effusions even in critically ill infants. The study also demonstrates shorter duration of chest tube requirement after initiation of sirolimus compared to previous studies. Larger multi‐institutional studies are needed to further support our findings.