Mechanistic Basis of Octreotide Therapy in Neonatal Postoperative Chylothorax: A Translational Case Report

Background and Clinical Significance: Octreotide is widely used off-label for neonatal postoperative chylothorax, although dosing is not standardised, and the supporting evidence comes mainly from case reports and case series. Somatostatin receptor (SSTR) subtypes 2 and 5 (SSTR2 and SSTR5) are expressed in the human thoracic duct, which provides a biological rationale for its use. Case Presentation: A term female neonate developed a massive left-sided chylothorax on initiation of enteral feeding, eight days after repair of a left congenital diaphragmatic hernia (CDH). Chest drainage yielded milky fluid with high triglyceride levels. Management comprised pleural drainage, total parenteral nutrition, fluid restriction, albumin, furosemide, antibiotics and continuous intravenous octreotide, started at 2 μg/kg/h and increased by 2 μg/kg/h daily to 12 μg/kg/h. Drainage declined after about 10 days, and radiological resolution after 20 days of treatment allowed for drain removal, extubation and reintroduction of feeding with a medium-chain triglyceride formula. Octreotide was tapered after 30 days. No treatment-related adverse events were observed. Conclusions: In this single case, postoperative chylothorax resolved during multimodal conservative management that included step-dose-escalated octreotide; the contribution of octreotide cannot be separated from that of the concurrent therapies. We discuss the differential diagnosis of pleural effusion after CDH repair and summarise the experimental rationale for octreotide, namely reduced splanchnic lymph production and an increased thoracic duct contraction rate ex vivo, which was not assessed in our patient. Prospective studies are needed to define evidence-based dosing and monitoring.