Case Report: Pediatric chylous ascites beyond congenital malformations—infectious causes and nutritional management with a literature review

Chylous ascites (CA) is a condition characterized by the accumulation of lymphatic fluid in the peritoneal cavity. Although congenital malformations are the most common cause in newborns, infectious agents represent a clinically significant, potentially reversible etiology that benefits from specific therapy. Various pathogens, including bacteria, viruses, fungi, and parasites, can alter the lymphatic system and lead to the leakage of chyle into the peritoneal cavity, resulting in nutritional, immunological, and metabolic deficiencies. We describe the case of a 5-month-old infant presenting with acute abdomen (vomiting, irritability, and abdominal distension) associated with elevated lipase levels. He underwent emergency laparotomy, which revealed chylous ascites in the absence of structural abnormalities. Initial empiric management, centered on the diagnosis of CA, included fasting and total parenteral nutrition (TPN), followed by a gradual dietary transition from a lipid-free milk formula to a formula enriched in medium-chain triglycerides (MCTs) and reduced in long-chain triglycerides, which was well tolerated. Cytomegalovirus (CMV) infection was identified as the underlying cause and confirmed by PCR on blood, urine, ascitic fluid, and gastric biopsies. The etiological diagnosis allowed for specific antiviral therapy, which, combined with nutritional support, led to complete resolution of the case. We also review published cases of infectious CA in children, analyzing the clinical presentation, diagnostic approaches, and therapeutic strategies. Particular attention is paid to nutritional management. Interventions including the use of TPN, fat-free formulas, or MCT-enriched formulas are also important in infectious etiologies for temporarily controlling the chyle loss mechanism while awaiting complete lymphatic restitution. This review emphasizes the importance of recognizing infectious etiologies in chylous ascites and emphasizes the critical role of personalized nutritional support in optimizing recovery.